Bioactive compounds from Ficus hirta Vahl extract: Molecular mechanisms underlying their anti-inflammatory and antibacterial activities

Abstract

Ficus hirta Vahl (F. hirta) is a traditional medicinal plant used for over 300 years in Chinese ethnic medical systems, including the Yao, Zhuang, and Dai. To provide a rigorous and balanced synthesis, this review conducted a systematic literature search across PubMed, Scopus, CNKI, and Web of Science, focusing on original research regarding the plant's phytochemistry and pharmacology. The extract contains diverse bioactive compounds, including flavonoids, phenolic acids, terpenoids, polysaccharides, and phenylpropanoids, which exhibit significant antibacterial and anti-inflammatory activities. This review summarizes their mechanisms of action: antibacterial effects are achieved through cell wall disruption, metabolic inhibition, and biofilm suppression; while anti-inflammatory effects involve modulating inflammatory mediators, enhancing antioxidant capacity, and regulating immune cells. Furthermore, the synergistic network between these properties and clinical effects—such as digestion promotion and cough relief—is explored. These findings provide a theoretical foundation for the medicinal development of F. hirta and highlight its potential in novel drug discovery.

Graphical abstract

Highlights

• •Traditional use: >300 years in Yao, Zhuang, Dai medicine.
• •Rich in bioactive compounds: flavonoids, phenolic acids, terpenoids, polysaccharides, phenylpropanoids.
• •Antibacterial: disrupts cell walls, inhibits metabolism & biofilm formation.
• •Anti-Inflammatory: modulates mediators, enhances antioxidant capacity, regulates immune cells.
• •Synergistic Value: network with other effects aids future drug development.

1. Introduction

Inflammatory diseases and drug-resistant bacterial infections continue to exhibit high global incidence rates. According to the World Health Organization (WHO, 2023), approximately 11% of the global population suffers from chronic inflammatory diseases, while mortality due to drug-resistant infections increases by 5% annually. Developing safe and effective prevention and treatment strategies based on natural products has thus become a critical focus in public health research.

Ficus hirta (family Moraceae), known as Cuyerong or Wuzhaolong, has its dried roots as the primary medicinal part. Historically documented since the Qing Dynasty for treating scabies, hemorrhoids, and arthritis, its traditional uses were later extended to immunomodulation and respiratory homeostasis, anti-inflammatory and diuretic actions, and gynecological diseases. Officially included in the Pharmacopoeia of the People's Republic of China (1977) and the Guangxi Yao Medicine Quality Standards (2013), F. hirta is now clinically applied for indigestion, cough, asthma, and hepatitis [1,2]. Contemporary studies have confirmed that extracts of F. hirta exhibit various biological activities, including antibacterial, anti-inflammatory, and antioxidant effects. The key bioactive compounds identified in these extracts include flavonoids, phenolic acids, terpenoids, and phenylpropanoids. Rather than merely moving from ethnopharmacological records to molecular pharmacology, recent studies have used this rich chemical profile—particularly the flavonoids and phenylpropanoids—as a direct bridge to link traditional efficacy with modern mechanistic evidence. For example, the flavonoid pinocembrin glycoside disrupts fungal cell membranes, while the phenylpropanoid bergamottin inhibits the NF-κB pathway, thereby providing molecular explanations for the plant's traditional anti-inflammatory and antibacterial uses. However, a critical gap remains: most evidence still comes from crude extracts rather than purified compounds, direct binding interactions between key active constituents and their putative protein targets have not been validated by in silico docking or enzymatic assays, and in vivo pharmacological data are still limited. Addressing this gap is essential for establishing the true molecular mechanisms underlying the traditional efficacy of F. hirta.

Contemporary studies have confirmed that extracts of F. hirta exhibit various biological activities, including antibacterial [3], anti-inflammatory [4], and antioxidant [5] effects. The key bioactive compounds identified in these extracts include flavonoids (e.g., quercetin, pinocembrin glycosides), phenolic acids (e.g., vanillic acid), terpenoids (e.g., triterpenes), and phenylpropanoids (e.g., psoralen) [6]. While studies have explored the direct antibacterial and anti-inflammatory mechanisms, systematic investigations into the “component-target-effect” relationships, peripheral indirect regulatory effects, and the potential of non-root parts (e.g., leaves and syconia) remain limited [7].

Although the applications of F. hirta in the food and pharmaceutical industries are expanding, the molecular mechanisms underlying its antibacterial and anti-inflammatory activities have not been systematically reviewed, and existing research remains fragmented. For instance, research is currently limited by a focus on crude extracts over purified compounds, which in turn hinders the application of in silico docking to validate the direct binding interactions between key active constituents (e.g., bergamottin, pinocembrin glycoside) and their putative protein targets (e.g., IKKβ, DNA gyrase). Moreover, conflicting or unquantified results exist regarding the regulation of pro-inflammatory cytokines such as IL-1β and TNF-α across different experimental models, and the crosstalk between antibacterial and anti-inflammatory pathways has not been systematically integrated. Therefore, this review focuses on elucidating the molecular mechanisms by which F. hirta extracts exert antibacterial and anti-inflammatory effects. It integrates current advances regarding its bioactive components, action pathways, and associated pharmacological effects, analyzes existing research limitations, and proposes future directions to provide a theoretical foundation for its further development and utilization.

For this review, a systematic literature search was conducted using the PubMed, Scopus, CNKI, and Web of Science databases, covering publications from database inception to 2025. The search strategy employed the following keywords in various combinations: “Ficus hirta”, “chemical constituents”, “antibacterial”, “anti-inflammatory”, and “molecular mechanism”. Relevant references identified through the initial search were manually screened for inclusion. Studies were selected based on their relevance to the phytochemistry, pharmacology, and molecular mechanisms of F. hirta, with priority given to original research articles and peer-reviewed reviews published in English or Chinese. Finally, a total of 104 studies were included in this review, as illustrated in the PRISMA flow diagram (Fig. 1). Based on findings from in vitro and in vivo models, this review explores both the direct molecular mechanisms underlying the antibacterial and anti-inflammatory effects of F. hirta extracts and the indirect pathways, such as immunomodulation and antioxidant defense, that contribute to its overall therapeutic efficacy.

Fig. 1.

PRISMA flowchart. This flowchart shows a transparent and reproducible account of our research strategy, clarifying how the reviewed literature was identified and selected.

2. Botanical characteristics and distribution of F. hirta

F. hirta, commonly known as “Five-finger Peach,” derives its name from its typically five-lobed leaves (though some may have three or seven lobes) and its hairy fruit [8]. The plant grows 1–2 m tall with an upright stem that exudes a white milky sap. Its leaves are alternate, oblong, lanceolate, or narrowly ovate, with finely serrated margins. It blooms in summer and bears fruit in autumn; the syconia grow in pairs on the branches and are covered with dense trichomes, a key diagnostic feature of this species [9]. As a perennial shrub, it thrives in valleys, woodlands, and slopes at elevations of 500–1000 m, preferring warm and humid climates with low cold tolerance [10,11].

Geographically, F. hirta is widely distributed across Southeast Asia (including Nepal, Bhutan, northeastern India, Vietnam, Myanmar, and Thailand). In China, it is primarily found in Yunnan, Guizhou, Guangxi, Guangdong, Hainan, Hunan, Fujian, and Jiangxi, ranking among the top ten renowned medicinal plants in southeastern China [2,12]. The accumulation of bioactive compounds in F. hirta is strongly influenced by growing conditions. For example, intercropping under rubber forests has been shown to increase the contents of nitrogen, potassium, and magnesium while decreasing calcium and iron levels, which indirectly promotes the biosynthesis of flavonoids and phenolic acids [13]. Plants cultivated at elevations above approximately 800 m exhibit 15%–20% higher flavonoid content compared to those grown in plains [14].

3. Traditional applications of F. hirta

The medicinal use of F. hirta spans multiple ethnic medical systems, with its documented applications continually expanding over time. Descriptions of its properties and clinical uses in historical texts align closely with modern reports. According to Traditional Chinese Medicine (TCM) theory, F. hirta has a sweet taste and acts on the lung, spleen, and liver meridians [15].

As a multi-ethnic herbal medicine, it is recorded in the medical texts of the Yao, Zhuang, Dai, Dong, Li, and Hani ethnic groups, detailing its medicinal value, botanical origins, and distribution [1]. The Qing-dynasty Sheng Cao Yao Xing Bei Yao first documented its use for “treating scabies, tinea, and hemorrhoids,” noting that “external washing with its decoction alleviates skin swelling and pain.” Zhi Wu Ming Shi Tu Kao expanded its applications to “arthritis and swelling,” emphasizing its ability to “promote tendon relaxation and activate collaterals” [2,16].

The 1932 Ling Nan Cai Yao Lu echoed earlier records, while the 1959 Zhong Yao Zhi specified its functions of “strengthening the spleen, nourishing the lungs, eliminating dampness, and relaxing tendons,” adding “use in gynecological disorders” [9]. Descriptions in Guangxi Min Jian Chang Yong Cao Yao Shou Ce, Xin Yi Xue Tong Xun, Hunan Zhong Cao Yao Dan Fang Xuan Ji, and Quan Guo Zhong Cao Yao Hui Bian were relatively concise [2,16]. Shi Yong Zhong Cao Yao listed clinical uses for gastric pain, bronchitis, and mastitis. The 1984 Zhong Guo Min Zu Yao Zhi recorded treatments for “indigestion, abdominal distension, pain, cough, neurasthenia, asthma, chronic hepatitis, and insufficient postpartum lactation” [17]. The 1999 Zhong Hua Ben Cao further extended applications to include “traumatic injuries, low back pain, and night sweats.”

In modern standards, F. hirta was included in the 1977 Pharmacopoeia of the People's Republic of China (Part One) and designated as a raw material for Chinese patent medicines in 2015. Beyond the roots, the syconia have gained attention for effects such as “promoting fluid production, relieving constipation, enhancing lactation, and boosting immunity,” used to address constipation and inadequate milk supply [17]. The plant is prepared in various forms: roots as decoctions, teas, medicinal wines, or functional foods, and syconia consumed fresh or processed into preserves [18].

Historical records indicate broad applications for indigestion, poor appetite, colds, pneumonia, tuberculosis, cough, asthma, night sweats, low back pain, trauma, arthritis, liver conditions, skin diseases, gynecological and pediatric disorders, with minimal adverse effects. It demonstrates particular efficacy in gastrointestinal ailments. In TCM theory, its core therapeutic mechanisms—tonifying the lungs and spleen, regulating qi, and resolving dampness—remain key research priorities.

4. Major active constituents of F. hirta

The medicinal properties of F. hirta are attributed to its diverse active constituents, the composition and concentration of which vary depending on the plant part used, extraction methods, and environmental conditions. Key active compounds are summarized in Fig. 2.

Fig. 2.

The major categories of identified active constituents in F. hirta and their representative chemicals. The active components including flavonoids (such as quercetin and pinocembrin glycosides), phenylpropanoids (e.g., psoralen), phenolic acids (e.g., vanillic acid), terpenoids (such as triterpenes), and polysaccharides. These compounds play key roles in various pharmacological activities such as antibacterial, anti-inflammatory, and antioxidant effects. Their structures are closely related to their bioactivities, providing a visual reference for understanding the material basis of F. hirta's efficacy.

4.1. Classification and structures of major constituents

4.1.1. Flavonoids

Flavonoids have garnered significant attention in drug development due to their diverse biological activities and complex mechanisms of action [19]. They represent the most extensively studied class of active constituents in F. hirta, characterized by a 2-phenylchromone core structure [20]. As primary active metabolites, flavonoids play crucial roles in plant growth and development, enhancing resistance to adverse environmental conditions while offering benefits to human health. Certain flavonoids also contribute to flower and fruit coloration and improve food flavor [21,22].

Flavonoids derived from F. hirta exhibit a broad spectrum of biological activities, including anti-inflammatory, antibacterial, antioxidant, anti-aging, antiviral, and anticancer effects [23]. Two novel flavonoids—naringenin-7-O-β-D-glucoside and pinostrobin-7-O-β-D-glucoside—have been isolated from the plant, with their structures elucidated through spectroscopic methods such as NMR and ESI-MS. These compounds demonstrate notable anticancer and free radical-scavenging activities [24]. Additionally, four common flavonoids (tricin, quercetin, vitexin, and cyclomulberrin) were identified using conventional methods, among which quercetin exhibits significant anti-inflammatory properties [25].

In F. hirta seedlings, flavonoids predominantly accumulate in the leaves and stems, with lower levels detected in the syconia [24]. Another study reported higher flavonoid content in root and leaf extracts compared to other plant parts [26]. These findings suggest that flavonoid accumulation is closely linked to cultivation environment and duration, leading to regional variations and increased content over time. To date, 34 flavonoids have been isolated from F. hirta, including identified and quantified compounds such as apigenin, luteolin, kaempferol, quercetin, and rutin. Notably, pinostrobin glycoside showed a minimum inhibitory concentration (MIC) of 200 mg/L against Penicillium italicum, functioning through disruption of the fungal cell membrane [27].

Beyond pinostrobin glycoside, several other bioactive compounds from F. hirta have been directly linked to specific antibacterial or anti-inflammatory activities. For instance, the coumarin bergapten (also known as 5-methoxypsoralen) isolated from F. hirta roots exhibited concentration-dependent inhibition of Staphylococcus aureus and Candida albicans, with minimum inhibitory concentration (MIC) values ranging from 32 to 128 μg/mL [11]. Additionally, the flavonoid quercetin, abundantly present in leaves, has been shown to reduce the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in LPS-stimulated macrophages by directly targeting iNOS and COX-2 enzymes, with IC₅₀ values of 15.2 μM and 8.7 μM, respectively [28]. Phenolic glycosides from F. hirta have been shown to decrease neuroinflammation in BV2 microglia cells, which may be regulated by inhibiting the activity of proteins in NF-κB, MAPK (JNK and ERK1/2), and AKT signaling pathways [4], demonstrating a clear structure–activity relationship where multiple phenolic hydroxyl groups are essential for activity. These examples underscore that the antibacterial and anti-inflammatory potencies of F. hirta are not merely a result of crude extract complexity but can be attributed to specific compound–target interactions. Future studies should further expand this library of compound–activity correlations to facilitate the development of standardized, mechanism-based phytotherapeutics.

Despite the isolation and identification of numerous flavonoids from F. hirta, detailed pharmacological studies for each compound remain limited [6]. Some flavonoids lack distinct bioactivities, suggesting the potential for discovering novel flavonoids from this plant in the future.

4.1.2. Phenylpropanoids

Phenylpropanoid metabolites in F. hirta can be classified into several categories, including simple phenylpropanoids, coumarins, lignans, bis-epoxylignans, and benzofuran lignans. Among these, coumarins represent a significant class of natural and synthetic oxygen-containing heterocyclic compounds characterized by a typical benzopyrone skeleton. Studies indicate that chemical modifications of coumarins can enhance their antibacterial activity [29,30].

Coumarin metabolites exhibit diverse biological activities such as anti-inflammatory, anticancer, and hepatoprotective effects, and may also be applied in the treatment of metabolic diseases [31]. Structural identification of (E)-styracitol was accomplished through spectroscopic analyses including NMR and high-resolution ESI-MS. Additionally, hydrated meranzin was detected in F. hirta using techniques such as mass spectrometry, infrared spectroscopy, UV spectroscopy, and NMR [28]. Both coumarins demonstrate notable antioxidant and anti-inflammatory activities [32,33].

Previous research has identified psoralen as the primary metabolite in the total coumarin fraction of F. hirta, with pharmacological studies revealing potent antibacterial, anticancer, anti-osteoporotic, and neuroprotective properties [34,35]. Recent investigations have highlighted both the high bioactivity and potential toxicity of certain coumarins, including hepatotoxic and nephrotoxic effects [36,37]. Overall, despite the isolation of multiple coumarins from F. hirta, detailed pharmacological profiling of individual compounds remains limited.

Given that the pharmacological activity of medicinal plants typically arises from the synergistic effects of multiple compound classes rather than from isolated constituents, it is essential to also consider other major metabolites in F. hirta, such as lignans. The stems, leaves, flowers, syconia, and roots of F. hirta also contain abundant lignans, which exhibit diverse structural variations and biological functions. Plant lignans themselves already serve as potent antioxidants capable of directly scavenging reactive oxygen species (ROS); furthermore, they require conversion into mammalian lignans (enterolignans) within the gastrointestinal microecological environment, a biotransformation that further modulates or “unlocks” their broader biological activities [[38], [39], [40]]. Lignans play significant roles in estrogen level regulation, neurodegenerative disease treatment, and tumor suppression [41,42]. Serving as plant defense compounds against environmental stress, lignans possess multiple bioactivities beneficial to human health [43].

As phytoactive metabolites with estrogenic or anti-estrogenic activities, lignans are categorized as phytoestrogens due to their ability to bind estrogen receptors (ER) and exert estrogen-like effects. This estrogenic property is directly relevant to the clinical application of F. hirta in promoting lactation: by binding to estrogen receptors in mammary tissue, these lignans may stimulate prolactin secretion and enhance mammary gland development, thereby improving postpartum breast milk secretion, quality, and yield. Thus, the traditional use of F. hirta as a galactagogue is likely mediated, at least in part, by the phytoestrogenic activity of its lignan constituents [44,45]. However, these metabolites are not exclusive to F. hirta and are present in other plant species.

4.1.3. Phenolic acids and phenolic glycosides

Phenolic compounds are widely distributed in the plant kingdom, occurring in roots, stems, leaves, and syconia [46,47]. These organic metabolites feature a benzene ring structure, with most exhibiting aromatic properties [48]. Phenolic metabolites derived from F. hirta demonstrate anticancer effects [49]. Among the identified phenolics are vanillin, vanillic acid, ∗p∗-hydroxybenzoic acid, syringic acid, ficusoside, euonymifolioside B, methyl syringate, and several others. Structurally, the presence of hydroxyl and methoxy substitutions on the benzene ring is critical for their bioactivity. For instance, euonymifolioside B, which contains multiple phenolic hydroxyl groups, exhibits significant anti-inflammatory activity by strongly inhibiting nitric oxide (NO) release in lipopolysaccharide (LPS)-induced Raw 264.7 cells, with an IC50 value of 14.31 μmol/L. Similarly, methyl syringate, characterized by its methoxy-substituted phenolic structure, contributes to the overall antioxidant and anti-inflammatory potential of the plant [6]. The identification methods for each compound are shown in Table 2.

Table 2.

Summary of major compound categories and identification methods in Ficus hirta.

Compound Category	Representative Compounds	Primary Identification Methods	References
Flavonoids	Naringenin-7-O-β-D-glucoside, Pinostrobin-7-O-β-D-glucoside	NMR, ESI-MS	[24]
Phenylpropanoids (Coumarins)	(E)-Styracitol, Meranzin hydrate	NMR, HR-ESI-MS, IR, UV	[28]
Phenolic Acids	Vanillin, Vanillic acid, p-Hydroxybenzoic acid, Syringic acid, Ficusoside,	HRESI-MS, HPLC, NMR, IR, UV	[72]
Phenolic Acids	Methyl syringate	IR, UV, NMR, ESI-MS	[25]
Phenolic Acids (additional)	(8R)-4,5′-Dihydroxy-8-hydroxymethyl-3′-methoxydeoxybenzoin, Methyl chlorogenate, Hydroquinone, Cresol	Ultrasound-assisted extraction + HPLC-MS/MS	[25]
Terpenoids and Liposoluble Constituents	Aldehydes (Hexanal, Heptanal, Octanal, Nonanal, etc.)	GC-MS	[66]
Volatile Components	Ethyl acetate	Steam distillation + analytical method	[65]

Phenolic glycosides are formed by condensation between phenolic hydroxyl groups in aglycone molecules and the anomeric carbon of sugars [50]. As natural metabolites widely present in syconia, vegetables, and medicinal herbs, phenolic glycosides are constituent components of F. hirta [51]. Similar to what has been observed in other phenolic glycoside-rich Chinese herbs such as Leonurus japonicus and Curculigo orchioides, the phenolic glycosides in F. hirta likely exert anti-inflammatory effects by suppressing protein activity in the NF-κB and MAPK (including JNK and ERK1/2) signaling pathways [52]. These mechanisms highlight their potential in alleviating neuroinflammation, particularly in BV2 microglial cells, and their broader application in treating neurodegenerative diseases. Phenolic glycosides also possess antioxidant [4]. Phenolic glycosides also possess antioxidant, anticancer, and immunomodulatory properties [53]. In F. hirta, they hold promise not only for drug development but also for food applications, where they enhance flavor and act as natural preservatives [54,55].

4.1.4. Terpenoids and liposoluble constituents

Terpenoids are important secondary metabolites in medicinal plants, with triterpenoids being the most frequently extracted compounds from F. hirta [56,57]. As essential organic molecules in plants, terpenoids are recognized for their diverse biological activities, including anti-inflammatory, antibacterial, antiviral, antitumor, antioxidant, and cardioprotective effects [58].

Regarding liposoluble constituents, quinones such as emodin and physcion have been isolated from F. hirta [25]. Quinones are natural and synthetic metabolites characterized by a fully conjugated cyclic unsaturated diketone structure. Emodin (1,3,8-trihydroxy-6-methylanthraquinone), a natural anthraquinone derivative, is found in many globally renowned medicinal herbs. Studies indicate that quinones exhibit various biological activities, including neuroprotective, antitumor, and nephroprotective effects [59,60]. Emodin has been isolated from F. hirta [61]; interestingly, it demonstrates diuretic and laxative properties, aligning with the traditional use of F. hirta for dampness removal and edema reduction. In addition to emodin, physcion has also been isolated from this plant [25]. As a constituent with potent antimicrobial properties, physcion demonstrates significant inhibitory effects against various pathogens. Its mechanism involves not only direct suppression of microbial growth but also the activation of host innate immune responses. This dual antimicrobial action supports the functional role of F. hirta's lipophilic quinones in defending against infectious agents.

Esters, another class of liposoluble constituents, are important components of plants, contributing to plant oils and imparting aromatic properties [62]. Formed through dehydration reactions between acids and alcohols [63], esters are known for their applications in pharmaceuticals, food, and cosmetics [64]. Steam distillation revealed that ethyl acetate constitutes 7%–15% of the volatile components in F. hirta [65].

Furthermore, eight aldehydes have been identified in F. hirta via gas chromatography–mass spectrometry (GC–MS): hexanal, heptanal, octanal, nonanal, (2E)-2-octenal, decanal, (2E)-2-nonenal, and 2-butyl-2-octenal [66]. Research shows that aldehyde profiles change significantly with increasing drying temperatures. Higher hot-air drying temperatures correlate with increased relative aldehyde content, rising from 6.86% at 40°C to 11.02% at 70°C [67].

4.1.5. Polysaccharides and other components

Polysaccharides are categorized into neutral and acidic polysaccharides, which exhibit immunomodulatory, antitumor, antiviral, and anti-inflammatory activities [68]. Among them, acidic polysaccharides demonstrate stronger biological activity, capable of inhibiting immunotoxicity and enhancing immune function [33].

F. hirta is also rich in mineral elements, with content levels in the order of: Ca > Mg > Mn > Fe > Cu > Pb [69]. The concentrations of mineral elements in leaves and syconia are higher than those in stems. Intercropping under rubber forests can increase the content of elements such as nitrogen, potassium, and magnesium, while reducing the levels of calcium and iron. Furthermore, environmental factors such as light spectrum have been shown to modify the nutritional status (e.g., nitrogen and phosphorus concentrations) and secondary metabolite accumulation in F. hirta [70]. The mechanism of action of the main individual components is shown in Table 1.

Table 1.

Mechanisms of action of each component.

Categories of monomeric components		Mechanism of action	References
Flavonoids	Luteolin7-O-Β-d-Glucopyranoside	Direct antibacterial: Destruction of fungal cell membranes	[3]、[27]
	Apigenin	Antibacterial and anti-inflammatory	[11]
	Quercetin	Immune regulation: Anti-inflammation	[25]
Phenylpropanoids	Bergamotene	Immune regulation: Inhibition of the NF-κB pathway	[12]、[11]
	Bergapten	Direct antibacterial and anti-inflammatory	[11]
	Meranzin hydrate	Antioxidant and anti-inflammatory	[28]
	Psoralen	Direct antibacterial	[35]
	Azelaic acid	Anti-inflammatory	[17]、[71]
	Phenolic Glycoside	Immune regulation: Inhibition of the NF-κB pathway、MAPK	[4]
Terpenes and fat-soluble	Triterpene	Immune regulation	[56]、[57]、[58]
	β-Amyrin acetate	Anti-inflammatory	[17]
	Ethyl acetate	Immune regulation: Antitumor	[25]
	Lupeol palmitate	Anti-inflammation: Inhibition of 5-LOX activity	[56]、[25]
Polysaccharides and other components	Daucosterol	Anti-inflammatory	[17]
	Polysaccharides	Immune regulation	[33]

4.2. Factors influencing composition

4.2.1. Differences in medicinal parts

The distribution of active components varies significantly among different medicinal parts. The root, traditionally used for medicinal purposes, is rich in triterpenoids and neutral polysaccharides [73,74]. Leaves are the primary accumulation site for flavonoids, with levels as high as 351.68 mg/100g—more than double that of stems [12]. Syconia are notable for their high content of acidic polysaccharides and minerals, and are known for their laxative and galactagogue effects. Given that leaves and syconia often exhibit higher or comparable bioactive compound levels than roots, their utilization could offer a more sustainable harvesting strategy. Unlike root extraction, which typically requires uprooting and destroying the whole plant, harvesting aerial parts allows the plant to regenerate, reducing ecological impact and supporting long-term resource availability.

4.2.2. Influence of extraction methods

The choice of extraction method significantly affects the yield of active components. Ethanol extraction (70% ethanol) yields notably higher amounts of flavonoids and phenolic acids compared to water extraction, with increases of 42% and 35%, respectively [3]. Ultrasonic-assisted extraction is more effective for terpenoids, achieving a 28% higher yield than traditional cold soaking while better preserving activity [58]. In contrast, water extraction is more suitable for polysaccharides, with a yield of up to 8.7% [75].

4.2.3. Environmental and cultivation conditions

Environmental factors significantly influence the accumulation of active components. Altitude is one influencing factor—F. hirta plants cultivated at elevations above 800 m exhibit 15–20% higher flavonoid content than those grown in plains [14]. Planting duration also plays a role: the triterpenoid content in roots peaks in three-year-old plants (1.2%), then slightly decreases with further growth [26] Additionally, intercropping systems, such as cultivation under rubber forests, can increase the contents of nitrogen and potassium in the plant [13,69]. Recent transcriptomic and metabolomic studies have begun to elucidate the molecular mechanisms underlying taproot development and bioactive compound biosynthesis in F. hirta, providing insights into the genetic regulation of these processes under different cultivation conditions [76].

5. Direct anti-inflammatory mechanisms of F. hirta extract

The anti-inflammatory effects of F. hirta are achieved through multiple targets and pathways, primarily involving the regulation of inflammatory mediators, enhancement of antioxidant capacity, and modulation of immune cell functions. These mechanisms collectively form a synergistic “anti-inflammatory–antioxidant–immunomodulatory” network. Its anti-inflammatory mechanism is illustrated in Fig. 3.

Fig. 3.

This diagram summarizes the multi-target mechanisms of F. hirta extract in regulating inflammatory and immune responses. The active constituents act through multiple pathways, including inhibition of NF-κB and MAPK signaling, reduction of pro-inflammatory cytokine release (e.g., TNF-α, IL-6, IL-1β), scavenging of free radicals, modulation of macrophage polarization (M1/M2 balance), and enhancement of T-cell function, synergistically contributing to its anti-inflammatory and immunomodulatory effects. Arrows in the diagram indicate the direction of signal transduction and regulation, while dashed lines represent inhibitory effects.

5.1. Regulation of inflammatory mediators

5.1.1. Targeted inhibition of the NF-κB signaling pathway

NF-κB is a central regulator of inflammatory responses. Upon activation, it initiates the transcription of pro-inflammatory genes such as TNF-α, IL-1β, and IL-6. Bergamottin, a compound present in F. hirta, directly binds to the ATP-binding domain of IKKβ with a binding energy of −8.2 kcal/mol. In a biological context, such a negative binding energy value indicates a strong and stable protein-ligand interaction—typically, values lower than −7.0 kcal/mol are considered to represent high-affinity binding. This strong interaction inhibits IKKβ phosphorylation and subsequently reduces the nuclear translocation efficiency of NF-κB, thereby attenuating the inflammatory cascade [12].

The regulatory role of F. hirta extract on the NF-κB signaling axis is particularly evident in liver injury-related inflammation. In mice with alcoholic liver injury, ethanol extracts significantly downregulated NF-κB activity, thereby lowering the levels of pro-inflammatory factors including TNF-α, IL-1β, and IL-6 [77]. In non-alcoholic fatty liver disease (NAFLD) models, F. hirta alleviated hepatic inflammatory infiltration and fibrosis by suppressing the expression of these pro-inflammatory cytokines. Studies have shown that the levels of sterol regulatory element-binding protein-1, acetyl-CoA carboxylase α, and stearoyl-CoA desaturase-1 were significantly reduced, while the levels of carnitine palmitoyltransferase 1α, acyl-CoA oxidase 1, and peroxisome proliferator-activated receptor α were markedly increased. The downregulation of IL-6, IL-1β, and TNF-α contributed to the mitigation of NAFLD [78].

Furthermore, N-phenolic glycosides from F. hirta ameliorated neuroinflammation in BV2 microglial cells, likely by inhibiting protein activities in the NF-κB and mitogen-activated protein kinase (MAPK, including JNK and ERK1/2) signaling pathways. These findings suggest its potential therapeutic application in neurodegenerative diseases [4].

As a core regulator of inflammation, NF-κB activation triggers the transcription of numerous downstream pro-inflammatory genes. The inhibition of this pathway by F. hirta serves as a key mechanism for modulating inflammation across multiple tissues. Under conditions such as aging or pathological stimulation in brain tissue, microglial overactivation promotes phosphorylation of the IκB kinase (IKK) complex, leading to degradation of the inhibitory protein IκBα. The released NF-κB dimer (p50/p65) rapidly translocate into the nucleus, binds to κB sites in the promoter regions of pro-inflammatory genes—including TNF-α, IL-1β, and IL-6—and drives their transcriptional expression. This positive feedback loop can cause an exponential increase in inflammatory cytokine levels, contributing to a neuroinflammatory cascade.

5.1.2. Regulation of lipid inflammatory mediators

The anti-inflammatory activity of bergamottin from F. hirta was investigated using colorimetric mass spectrometry, LCMS-IT-TOF, and GC–MS. Bergamottin simultaneously inhibits cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX): it competitively occupies the substrate channel of COX-2 (molecular docking score: −9.3), thereby reducing prostaglandin E₂ (PGE₂) synthesis, and blocks the conversion of leukotriene A₄ (LTA₄), reducing neutrophil production [11].

In a xylene-induced mouse ear edema model, the aqueous extract of F. hirta significantly reduced ear swelling in a dose-dependent manner, indicating that it exerts anti-inflammatory action by suppressing local hyperemia and edema [17].

Additionally, several isolated phenolics from F. hirta exhibited strong inhibition of nitric oxide (NO) release in lipopolysaccharide (LPS)-induced RAW 264.7 cells, with IC₅₀ values ranging from 12.96 to 46.08 μmol/L, demonstrating significant anti-inflammatory activity [72].

5.1.3. Blockade of inflammatory cell recruitment

In a tail-cutting–induced zebrafish inflammation model, bergamottin significantly inhibited the recruitment of neutrophils and macrophages to the injury site, as well as the production and re-release of reactive oxygen species (ROS) and nitric oxide (NO). Another study suggested that bergamottin may contribute to the treatment of chronic inflammatory diseases by reducing ROS and NO release, thereby blocking the amplification of the inflammatory cascade [11].

Collectively, these studies demonstrate that F. hirta effectively suppresses both acute and chronic inflammation by targeting key inflammatory signaling pathways and mediators.

5.2. Antioxidant effects and mechanisms

5.2.1. Direct scavenging of free radicals

Antioxidant activity is crucial for human health, as it inhibits or reduces damage caused by free radicals within cells. This effect relies on multiple active components (such as flavonoids and polysaccharides), which demonstrate significant free radical scavenging capacity in vitro.

For example, polysaccharides, flavonoids, polyphenols, and amino acids from F. hirta all exhibit scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. When calculated based on dried powder weight, the ethyl acetate extract contained the highest total flavonoid content, while the methanol extract had the highest total phenolic content.

In terms of DPPH radical scavenging activity, various solvent extracts of Ficus hirta fruits demonstrated potent antioxidant capacity. Among them, the ethyl acetate extract (EAE) and acetone extract (AE) exhibited the strongest DPPH radical scavenging activity, with IC₅₀ values of 2.52 mg/mL and 2.02 mg/mL, respectively. These extracts also showed significant ABTS radical scavenging activity, with IC₅₀ values of 3.06 mg/mL and 9.26 mg/mL, respectively [79].

Among the flavonoids, luteolin demonstrated particularly prominent antioxidant activity—significantly stronger than that of apigenin and psoralen [5]. These components directly neutralize free radicals by donating hydrogen atoms or electrons, thereby reducing cellular damage.

5.2.2. Inhibition of cellular senescence

Free radicals are considered a major contributor to the aging process. F. hirta extract, rich in antioxidant compounds, effectively scavenges free radicals. This antioxidant activity plays a crucial role in protecting cells from free radical-induced damage, thereby preventing cellular senescence and ultimately delaying the overall aging process.

F. hirta extract, rich in antioxidant compounds, effectively scavenges free radicals. Studies have demonstrated that various solvent extracts of F. hirta fruits exhibit potent antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals [79]. Using UPLC-PAD-MS fingerprinting combined with cluster analysis, Yi et al. quantified four active components in F. hirta root and evaluated their antioxidant potencies; the results demonstrated that luteolin was the most effective DPPH radical scavenger, apigenin exhibited moderate potency, whereas the coumarins psoralen and bergapten possessed little effect against free radical reactions [5]. This antioxidant activity plays a crucial role in protecting cells from free radical-induced damage, thereby preventing cellular senescence and ultimately delaying the overall aging process.

The antioxidant effects of F. hirta extracts have been demonstrated in multiple in vivo models. Chen et al. summarized that F. hirta improved memory function in Alzheimer's disease (AD) model mice, as assessed by the Morris water maze test, and mechanistic investigations revealed that F. hirta alleviated oxidative damage in brain tissue by reducing malondialdehyde (MDA) content and enhancing superoxide dismutase (SOD) activity [17]. In a separate study, a F. hirta polysaccharide (FHVP-2) was shown to effectively protect RAW264.7 cells from H₂O₂-induced oxidative damage by reducing MDA levels and increasing SOD activity [80]. These findings collectively confirm the potent antioxidant capacity of F. hirta as well as its potential to inhibit cellular senescence through the attenuation of oxidative stress.

5.2.3. Enhancement of the antioxidant enzyme system

In animal models, the antioxidant effects of F. hirta are more intuitively reflected in the regulation of oxidative stress markers. Malondialdehyde (MDA) and superoxide dismutase (SOD) are widely recognized indicators of antioxidant-mediated mitigation of damage.

The anti-fatigue and antioxidant effects of F. hirta have been demonstrated in multiple in vivo studies. Chen et al. summarized that F. hirta could reduce MDA levels while increasing SOD and GSH levels, GSH-Px activity, and the expression levels of Nrf2 and its downstream related antioxidant enzymes HO-1 and SOD-1 proteins to play an antioxidant role [17]. Beyond directly assessing antioxidant enzyme activities, metabolomic analyses have further elucidated the mechanisms. Using UHPLC-Orbitrap/MS-based metabolomics, Zhou et al. identified 20 differential metabolic markers in serum of CCl₄-induced liver injury mice compared to normal controls, which were mainly related to the metabolism of amino acids and fatty acids. Most of these biomarkers were ameliorated by F. hirta pretreatment, and pathway analysis revealed that the therapeutic actions of F. hirta were mainly involved in the regulation of oxidative stress responses and energy homeostasis [81].

In a d-galactose-induced aging mouse model, both aqueous and ethanol extracts of F. hirta increased the activities of SOD, glutathione peroxidase (GSH-Px), and catalase (CAT) in thymus and spleen tissues to varying degrees, while decreasing MDA levels in serum and liver tissue [82]. These antioxidant enzymes work synergistically to scavenge free radicals and maintain the balance between oxidation and antioxidation. Beyond mammalian models, an in vivo study in the Pacific white shrimp (Penaeus vannamei) revealed that F. hirta promotes antioxidant enzyme activity under ammonia stress by inhibiting the expression of miR-2765, leading to increased activities of SOD, CAT, and GPx, and reduced mortality [83]. This miRNA-mediated mechanism expands our understanding of the antioxidant regulation of F. hirta across different animal phyla.

In summary, F. hirta, rich in active compounds such as polyphenols, flavonoids, and polysaccharides, demonstrates potent antioxidant capacity. It not only directly scavenges free radicals like DPPH and ABTS but also significantly enhances the activity of endogenous antioxidant enzymes including SOD and GSH-Px, effectively reducing the levels of oxidative damage markers such as MDA. This multi-pathway antioxidant mechanism underlies its notable efficacy in delaying cellular senescence, improving symptoms of Alzheimer's disease, and mitigating oxidative stress injury, offering a natural strategy for preventing and treating oxidative stress-related diseases.

5.3. Bidirectional regulation of immune cells

The immune system serves as the most critical defense mechanism against pathogen invasion. Many plants are used in the treatment of various diseases due to their immunomodulatory properties. Growing evidence indicates that F. hirta can enhance both non-specific and specific immunity, improve immune system regulation, and has potential applications in treating conditions such as myelosuppressive anemia, hemorrhagic anemia, and myasthenia gravis [75,84].

In cyclophosphamide-induced immunocompromised mice, F. hirta significantly increased the carbon clearance rate, elevated thymic and splenic weight indices, and enhanced serum hemolysin levels. These results demonstrate its regulatory effects on immune function [17,85].

5.3.1. Regulation of macrophage polarization

In terms of macrophage polarization, the active component bergamottin modulates phenotypic transformation via a dual-pathway mechanism: on one hand, it suppresses the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signaling axis, inhibiting lipopolysaccharide (LPS)-induced IKKβ phosphorylation, which reduces inducible nitric oxide synthase (iNOS) expression and decreases the release of reactive oxygen species (ROS) and nitric oxide (NO). On the other hand, bergamottin activates peroxisome proliferator-activated receptor γ (PPARγ), promoting macrophage transition to the anti-inflammatory M2 phenotype, as indicated by increased arginase-1 (Arg-1) activity and elevated interleukin-10 (IL-10) secretion. This polarization balance alleviates tissue inflammatory injury [11].

Given the established role of the gut-immune axis in linking gastrointestinal function with systemic immunity, it is relevant to examine how F. hirta affects digestive processes as part of its immunomodulatory profile. To further evaluate immunomodulatory effects, mice were divided into five groups (n = 10 per group): a blank control group, an Astragalus group, and low-, medium-, and high-dose F. hirta groups. After one week of treatment, observations were made regarding gastric emptying and intestinal motility. Both Astragalus and F. hirta enhanced gastric emptying, with the medium- and low-dose F. hirta groups showing significant effects (P < 0.01), while Astragalus and the high-dose F. hirta group exhibited non-significant outcomes.

Neither treatment significantly altered total gastric acidity, total acid output, or pepsin activity (P > 0.05). However, pepsin activity was higher in all F. hirta groups compared to the Astragalus group, with the medium- and low-dose groups showing statistically significant increases. These results indicate that both Astragalus and F. hirta enhance macrophage phagocytic function, thereby strengthening non-specific immunity, promote serum antibody production to improve humoral immunity, and boost cellular immunity—with F. hirta demonstrating superior efficacy in these immunomodulatory activities. This superior performance suggests that F. hirta holds significant potential for further development and application [85].

5.3.2. Balance of T-cell subsets

Fifty mice were randomly assigned to a normal saline control group, a cyclophosphamide model group, and F. hirta aqueous extract groups (6.6, 4.4, and 2.2 g/kg). An immunosuppressed mouse model was established by intraperitoneal injection of cyclophosphamide. After 14 consecutive days of oral administration, the F. hirta aqueous extracts (6.6 and 4.4 g/kg) significantly increased the spleen index and enhanced macrophage phagocytosis, T-lymphocyte proliferation, and cytotoxic activity. The number of T-cell subsets and the levels of interleukin (IL)-1 and interferon-γ were elevated in the treatment groups. These results indicate that the aqueous extract of F. hirta can improve immune function in immunosuppressed mice, and its mechanism is associated with the regulation of cellular immunity [75].

5.3.3. Protection of the immune barrier

The protective effect of F. hirta on the immune barrier was evaluated in vitro by assessing its influence on lipopolysaccharide (LPS)-induced apoptosis. In this study, the apoptosis receptor Fas was cloned, containing a 39 bp 5′-untranslated region, a 951 bp open reading frame, a 316-amino acid protein, and an 845 bp 3′-untranslated region. EcFas expression was strongest in the spleen tissue of the grouper (Epinephelus coioides). LPS-induced apoptosis in fish splenocytes was concentration-dependent. These findings provide evidence that treatment with F. hirta alleviates LPS-induced apoptosis by activating miR-411 to suppress Fas expression, thereby maintaining immune cell quantity and function and enhancing pathogen clearance capacity [86].

F. hirta exerts immunomodulatory effects through multiple mechanisms, including regulating macrophage polarization, balancing T-cell subsets, and protecting the immune barrier. Its active component, bergamottin, bidirectionally modulates macrophage function—suppressing pro-inflammatory M1 polarization while promoting anti-inflammatory M2 transition. It also significantly enhances T-lymphocyte activity and ameliorates immunosuppression. Furthermore, by regulating miRNA expression, it inhibits immune cell apoptosis and helps maintain immune homeostasis. This multi-target immunomodulatory profile underlies its marked efficacy in improving immunodeficiency, mitigating excessive inflammatory responses, and strengthening host defense capabilities, offering a natural strategy for intervening in immune-related diseases.

6. Direct antimicrobial mechanisms of F. hirta extract

The antimicrobial effects of F. hirta target both bacteria and fungi through multiple mechanisms, including disruption of microbial structures, inhibition of metabolic pathways, and prevention of biofilm formation, while synergizing with the host's immune function. Its antibacterial mechanism is shown in Fig. 4.

Fig. 4.

This diagram summarizes the multiple mechanisms through which F. hirta extract inhibits the growth of bacteria and fungi. The active components act by directly disrupting microbial cell wall/membrane integrity, interfering with energy metabolism and biosynthetic pathways, and inhibiting biofilm formation, while also indirectly suppressing pathogen proliferation through modulation of host immune responses, such as enhancing macrophage phagocytosis. The diagram illustrates the multi-level synergistic effects involved in its antibacterial and antifungal activity, providing a mechanistic basis for its potential application in anti-infection therapies.

6.1. Disruption of microbial cell walls/membranes

6.1.1. Targeted damage to fungal cell walls

F. hirta exhibits significant inhibitory effects against Penicillium italicum and Penicillium digitatum. Studies have shown that it induces fungal cell death by disrupting the integrity of the mycelial cell membrane and cell wall. The flavonoid pinocembrin glycoside, obtained from the fruit of F. hirta, was evaluated for its antifungal activity against P. italicum. In vitro tests demonstrated that pinocembrin glycoside inhibits mycelial growth, with a minimum inhibitory concentration (MIC) of 200 mg/L and a minimum fungicidal concentration (MFC) of 800 mg/L [3,27]. These findings further confirm its targeted damaging effect on fungal cell walls in a concentration-dependent manner.

6.1.2. Interference with bacterial cell wall

F. hirta exhibits significant antibacterial activity. Ya et al. isolated two novel phenolic compounds from the roots of F. hirta, which showed significant antibacterial activities against various terrestrial pathogenic bacteria, including Staphylococcus aureus and Bacillus subtilis, with minimum inhibitory concentration (MIC) values ranging from 1.30 to 39.93 μM [32]. Similarly, the ethanol extract of F. hirta fruits demonstrated good antifungal activity against Penicillium italicum with an MIC of 200 mg/L [79]. These findings indicate that F. hirta extracts and their bioactive constituents can effectively inhibit the growth of both Gram-positive and Gram-negative bacteria.

Further studies using F. hirta roots employed micro-colorimetric, disc diffusion, and twofold serial dilution methods to assess antibacterial activity. Optimization via the thiazolyl blue tetrazolium bromide (MTT) assay established ideal conditions: initial bacterial concentration of 10⁵–10⁶ CFU/mL and MTT concentration of 0.5 mg/mL. Under these conditions, the aqueous extract inhibited E. coli and S. aureus, with MICs of 11.21 mg/mL and 14.07 mg/mL, respectively. Both disc diffusion and serial dilution methods confirmed the extract's antibacterial properties [87].

Notably, the MIC values for E. coli differ substantially between these two studies (1 g/mL vs. 11.21 mg/mL). This discrepancy may be attributed to several factors: differences in the plant part used (unspecified vs. roots), extraction protocols (simple aqueous extraction vs. micro-colorimetric optimization), bacterial strain variations, or the specific endpoints measured by different assay formats. Such variability highlights the need for standardized methodologies when comparing antibacterial potency across studies.

The bacterial cell wall—particularly the peptidoglycan layer in Gram-positive bacteria and the outer membrane in Gram-negative bacteria—is essential for cellular integrity. Structural disruption can lead to cell lysis. The inhibitory effects of F. hirta suggest it may act by interfering with cell wall synthesis or directly damaging the cell wall structure.

6.2. Inhibition of bacterial metabolic pathways

6.2.1. Blockade of energy metabolism

Pinocembrin-7-O-β-D-glucoside, isolated from F. hirta, is a significant antimicrobial metabolite exhibiting concentration-dependent antibacterial activity. While direct molecular docking or enzyme inhibition studies are currently lacking for this specific compound, a proposed mechanism—based on structural analogs with similar flavonoid backbones—suggests that it may function by disrupting bacterial energy metabolism or biosynthetic pathways [88]. For instance, bacterial energy metabolism relies on processes such as glycolysis and the tricarboxylic acid cycle; inhibition of these pathways can result in insufficient ATP production, impairing bacterial growth and division. Similarly, obstruction of biosynthetic pathways—including amino acid and nucleic acid synthesis—directly suppresses bacterial proliferation [89]. Pinocembrin-7-O-β-D-glucoside may target key enzymes in these metabolic routes, such as competitively binding to chorismate mutase to inhibit prephenate formation. This leads to a deficiency in aromatic amino acids, ultimately disrupting bacterial metabolism [24].

6.2.2. Modulation of host metabolism to assist antibacterial effects

In host models of bacterial infection, F. hirta indirectly suppresses bacterial proliferation by modulating metabolic processes. For example, in lipopolysaccharide (LPS)-induced apoptosis of fish splenocytes, treatment with F. hirta inhibits Fas expression by activating miR-411, thereby attenuating apoptosis [86]. LPS, a component of the Gram-negative bacterial cell wall, triggers apoptosis that disrupts immune barriers and facilitates bacterial dissemination. By protecting immune cells and maintaining metabolic homeostasis, F. hirta indirectly mitigates bacterial infection progression.

Additionally, F. hirta demonstrates protective effects against carbon tetrachloride-induced acute liver injury in mice by regulating amino acid and fatty acid metabolism [81]. As the liver serves as a metabolic hub, improved metabolic function enhances the clearance of bacterial toxins, further supporting antibacterial responses. In a rat model of spleen deficiency, F. hirta aqueous extract has been shown to enhance digestive system function [78]. Furthermore, F. hirta polysaccharides have been demonstrated to modulate the gut microbiota by enriching beneficial genera such as Faecalibacterium, Bifidobacterium, and Bacteroides, while suppressing opportunistic pathogenic genera including Dorea and Clostridium XIVa, thereby indirectly reducing intestinal bacterial overgrowth [80].

These findings indicate that the antibacterial mechanisms of F. hirta extend beyond direct metabolic inhibition of bacteria to include modulation of host metabolism, thereby suppressing bacterial growth and dissemination through dual pathways.

6.3. Inhibition of biofilm formation

6.3.1. Suppression of microbial aggregation

Biofilms are community structures formed by microorganisms (e.g., bacteria and fungi) to adapt to their environment. Composed of the microbes themselves and their secreted extracellular matrix (e.g., polysaccharides, proteins, nucleic acids), biofilms exhibit strong drug resistance and pathogenicity. Their formation depends on initial microbial adhesion, aggregation, and extracellular matrix secretion.

F. hirta inhibits the growth of pathogenic bacteria such as Staphylococcus aureus and Escherichia coli [87], thereby reducing the initial microbial load and lowering the likelihood of biofilm formation at its source. Since biofilm development requires a critical density of microbial populations, a decline in pathogen numbers significantly delays this process.

Regarding fungal biofilms, F. hirta suppresses species such as Penicillium italicum and Penicillium digitatum. For instance, flavonoids like pinocembrin glycosides extracted from F. hirta syconia inhibit the secretion of fungal hydrophobins, reducing spore surface hydrophobicity by 37% and hindering surface colonization [3,27]. This reduction impairs fungal spore adhesion and aggregation. Furthermore, damage to the cell wall interferes with the fungi's ability to secrete extracellular matrices, as cell wall integrity is essential for the synthesis and secretion of extracellular components.

6.3.2. Disruption of mature biofilms

Furthermore, F. hirta enhances host immune functions—such as improving macrophage phagocytic capacity and T-cell activity—thereby accelerating the clearance of planktonic microbes and microorganisms on biofilm surfaces. This process further impedes biofilm maturation. For example, macrophages eliminate microbes at the periphery of biofilms through phagocytosis, while T-cells recognize and lyse infected cells encapsulated within biofilms. Enhanced functionality of these immune cells effectively suppresses biofilm expansion [75].

Although no studies have directly demonstrated the disruption of mature biofilm structures by F. hirta, its proven antibacterial mechanisms—particularly the ability to inhibit microbial growth and reduce the initial microbial load—strongly suggest potential anti-biofilm properties. By lowering the density of planktonic bacteria, F. hirta likely interferes with the early stages of biofilm formation, as biofilm development requires a critical threshold of microbial populations. Future research employing in vitro biofilm models (e.g., crystal violet staining to quantify biofilm biomass) could further validate this activity and support its application in chronic infections, which are often associated with biofilms.

In summary, F. hirta interferes with key stages of biofilm formation through multiple mechanisms, representing a critical extension of its broad-spectrum antibacterial effects.

7. Synergistic effects of related pharmacological actions

The antibacterial and anti-inflammatory activities of F. hirta interact with its other pharmacological effects, forming a multi-system regulatory network that enhances overall therapeutic efficacy.

7.1. Auxiliary role in promoting digestion

As a renowned traditional herbal medicine in multiple Asian countries, F. hirta has demonstrated significant efficacy in treating digestive disorders by promoting food digestion and regulating spleen, stomach, and gastrointestinal function [28]. F. hirta is commonly used to alleviate digestive disturbances. The polysaccharides derived from F. hirta (FHVPs) have been shown to possess excellent digestive stability and prebiotic effects through modulation of the gut microbiome [90], thereby contributing to the regulation of gastrointestinal function and the promotion of digestion and absorption. Consistent with previous findings, another study reported that F. hirta exerts a bidirectional regulatory effect on intestinal propulsion—both enhancing and inhibiting motility—improving gastrointestinal dynamics and facilitating digestion and absorption [17,90].

Importantly, the gastroprotective effect of F. hirta is closely linked to its anti-inflammatory and antioxidant molecular mechanisms. For instance, flavonoids such as quercetin—abundantly present in F. hirta—are known to reduce gastric mucosal injury by inhibiting the production of pro-inflammatory cytokines (e.g., TNF-α, IL-6) and scavenging reactive oxygen species (ROS) in the gut lining. Thus, the digestive benefits of F. hirta are not merely functional but are underpinned by its ability to modulate local inflammation and oxidative stress. In further research, using normal rats as controls, a rat model of gastric mucosal injury induced by pyloric ligation was established. The aqueous extract of F. hirta (2 g/mL) was shown to reduce gastric acid secretion and pepsin activity, indicating a protective effect against gastric mucosal damage [17]. Another study created a gastric injury model in rats via subcutaneous injection of indomethacin. Forty-two male SD rats were randomly divided into a normal group, a model group, and high- and low-dose F. hirta extract groups (14 g/kg and 7 g/kg, respectively). Gastric mucosal damage was observed in the model group, while intragastric administration of F. hirta ameliorated these injuries. The mechanism was linked to the extract's influence on the expression of connexin proteins and the transcription factor SOX2 [91].

F. hirta is widely recognized for its ability to regulate gastrointestinal function and alleviate digestive disorders. In vitro studies have demonstrated that a polysaccharide-zinc complex derived from F. hirta (FHVP–Zn) effectively protects intestinal epithelial cells from oxidative stress and inflammatory damage. Specifically, FHVP-Zn significantly increases trans-epithelial electrical resistance (TEER), reduces permeability, and reverses the injury-induced downregulation of tight junction proteins ZO-1 and Claudin-1, while also inhibiting the mRNA expression of key pro-inflammatory cytokines (IL-6, IL-8, IL-1β) in a dose-dependent manner. Collectively, FHVP-Zn protects intestinal barrier integrity through synergistic antioxidant, barrier-maintaining, and anti-inflammatory actions, thereby supporting gastrointestinal motility and digestive function [92]. From an antibacterial perspective, this improvement in digestive function has important implications. Enhanced gastrointestinal motility and secretion help prevent bacterial overgrowth in the small intestine by reducing stasis and limiting the time available for microbial colonization. Furthermore, improved nutrient absorption supports host nutritional status, which is essential for maintaining robust immune function—including the production of antibodies and the activity of phagocytic cells. Thus, by promoting digestion and gut motility, F. hirta indirectly contributes to host defense against infections.

Thus, the role of F. hirta in promoting digestive function warrants considerable attention.

7.2. Coordinated anti-tussive and anti-asthmatic effects

The traditional use of F. hirta for cough and asthma is grounded in its ability to suppress key inflammatory mediators that drive airway hyperresponsiveness and mucus hypersecretion. Specifically, F. hirta inhibits the NF-κB pathway, reduces COX-2-derived PGE₂, and lowers NO production—each of which directly contributes to bronchodilation, reduced cough reflex sensitivity, and decreased airway inflammation. Network pharmacology studies have revealed that F. hirta plays antitussive and anti-sthmatic roles by acting on targets such as estrogen receptor 1, epidermal growth factor receptor, and cyclooxygenase [11]. Moreover, emerging evidence indicates that bergapten, a key coumarin component of F. hirta, attenuates acute lung injury and airway inflammation in asthma models by regulating the Th17/Treg balance and inhibiting MRGPRX2-mediated mast cell activation [93,94]. Multiple studies have confirmed that F. hirta extracts improve gastrointestinal motility, promote digestion and absorption, and exhibit significant antitussive, expectorant, and anti-sthmatic activities. Collectively, these findings elucidate the dual therapeutic potential of F. hirta in both respiratory and digestive disorders through a synergistic network of anti-inflammatory, immunomodulatory, and antioxidant mechanisms.

In one study, 72 mice (equal numbers of males and females) were randomly assigned to six groups: a control group, a positive control group, an Astragalus aqueous extract group (10 g/kg), and high- (20 g/kg), medium- (10 g/kg), and low-dose (5 g/kg) F. hirta aqueous extract groups. The positive control group received Astragalus extract (10 mg/kg) via intragastric administration, while the control group was given an equal volume of distilled water for five consecutive days. F. hirta extract reduced the frequency of ammonia-induced coughing in mice, indicating antitussive effects. In an anti-asthmatic assay, guinea pigs were divided into six groups: normal control, positive control, Astragalus extract (8 g/kg), and high- (16 g/kg), medium- (8 g/kg), and low-dose (4 g/kg) F. hirta extract groups, receiving treatment for seven days. Various doses of F. hirta prolonged asthma remission time, confirming its anti-asthmatic properties [95].

In the same experiment, the voltage threshold for inducing cough was measured by electrically stimulating the mice nerve within the afferent pathway of the cough reflex. Results showed a significant increase in the voltage threshold required to trigger coughing after treatment with F. hirta. Additional research demonstrated that its ethanol extract possesses notable antitussive and potent anti-asthmatic effects, significantly extending asthma latency [96]. Recent clinical studies also support that preparations of F. hirta help alleviate asthma symptoms [97,98].

This review demonstrates that F. hirta effectively reduces bronchiolitis in a rat model of chronic obstructive pulmonary disease induced by cigarette smoke and lipopolysaccharide (LPS)—a classic trigger of both inflammatory and infectious responses. By dampening the LPS-induced inflammatory cascade in lung tissue, F. hirta alleviates key respiratory symptoms, including cough, expectoration, and asthma, while also preventing the decline in lung function. This anti-inflammatory mechanism, involving the suppression of pro-inflammatory cytokines and the NF-κB signaling pathway, underlies the therapeutic potential of F. hirta in chronic respiratory diseases associated with infection and inflammation. [95]. Notably, these network pharmacology-derived targets are not isolated to the respiratory tract but also play pivotal roles in systemic inflammation and immune regulation. For instance, estrogen receptor 1 (ESR1) and epidermal growth factor receptor (EGFR) are involved in airway remodeling and mucus hypersecretion, yet they also modulate macrophage polarization and pro-inflammatory cytokine release in peripheral tissues. Cyclooxygenase (COX) enzymes, particularly COX-2, drive both pulmonary inflammation (via PGE₂-induced bronchoconstriction) and systemic inflammatory cascades. Phosphatidylinositol 3-kinase (PI3K) and glycogen synthase kinase-3 (GSK-3) are central nodes in the NF-κB and MAPK signaling pathways, linking local airway inflammation to broader immune responses. This target overlap—where the same molecular hubs regulate both respiratory symptoms and systemic inflammation—provides a mechanistic rationale for the pleiotropic therapeutic effects of F. hirta extracts. It supports the view that the plant's bioactivity is not merely the sum of isolated compound actions but emerges from a synergistic network that concurrently addresses pathogen clearance and host immune modulation [17,99]. These findings elucidate the mechanisms behind the cough-suppressing, expectorant, and anti-asthmatic actions of F. hirta, providing a foundation for developing new drugs for respiratory conditions.

8. Research limitations and future directions

8.1. Current limitations

Current research on the extraction of active compounds from F. hirta primarily focuses on the enrichment and purification of flavonoids, polysaccharides, psoralen, and other bioactive constituents. Techniques such as ultrasonic extraction, microwave-assisted extraction, and enzyme-assisted extraction are commonly employed. While obtaining high-purity, high-activity components is essential for further pharmacological and application studies, existing extraction methods still exhibit room for improvement in efficiency, specificity, and scalability. Future efforts leveraging technological innovations can continuously optimize extraction strategies, thereby enhancing the usability and value of F. hirta in modern research.

Pharmacological studies have confirmed the broad biological activities of F. hirta; however, most existing research remains at the level of crude extracts. A particularly notable gap is the lack of studies investigating the synergistic molecular interactions between different classes of bioactive compounds—such as flavonoids and polysaccharides—which likely work together to produce the plant's observed therapeutic effects. Investigations into single compounds have mainly centered on psoralen, while the exploration of other active ingredients—such as phenolic acids, flavonoids, and polysaccharides—remains limited. Consequently, the molecular mechanisms underlying the synergistic anti-inflammatory and antibacterial actions of these components have not been fully elucidated. Related pharmacological mechanisms are largely confined to experimental stages, lacking in-depth clinical validation. Addressing these gaps will strengthen the systematic analysis of its bioactive components and promote the translation of mechanistic research into clinical applications, providing a robust scientific foundation for further development and utilization of F. hirta [100].

Another significant limitation concerns the safety assessment of F. hirta extracts. Although certain coumarins present in the plant (e.g., psoralen) are known to exhibit hepatotoxicity and photosensitizing effects [36,37], none of the in vivo studies cited in this review have systematically evaluated the safety margin or toxicity endpoints of F. hirta extracts. Most efficacy studies administered doses up to 20 g/kg in mice without reporting overt adverse effects; however, these observations do not constitute formal toxicological evaluations such as determination of LD₅₀, subchronic toxicity, or phototoxicity testing. Therefore, the therapeutic window and long-term safety of F. hirta—particularly with respect to coumarin-related risks—remain poorly characterized, representing a critical gap for future clinical translation.

In 2023, F. hirta was officially included in the Guangdong Lingnan Chinese Medicinal Materials Protection List, signifying official recognition of its medicinal value and growing academic interest. Although certain foundations have been established in areas such as cultivation, chemical composition, quality control, and pharmacological activity, research on genetic breeding and resource conservation remains insufficient [15]. In terms of industrial application, F. hirta has been used in the preparation of proprietary Chinese medicines such as Fuyanjing Capsules, Huofeigong Tablets, and Fuguanning Formula, demonstrating potential for clinical use. However, market promotion and product development are still in their early stages [92]. To further enhance the resource value of F. hirta, modern scientific approaches should be actively introduced to systematically advance the identification of active substances, particularly the synergistic molecular interactions among compound classes, and clinical translation, thereby supporting efficient resource utilization and industrial upgrading.

8.2. Future directions

A promising strategy for future research involves utilizing molecular dynamics simulations coupled with point mutation validation to confirm the specific interaction between bergamottin and the ATP-binding domain of IKKβ kinase (key hydrogen bond with Tyr-108/hydrophobic pocket Val-152). This would elucidate the structure-activity basis of its inhibition of the NF-κB pathway [77]. Similarly, enzyme kinetics and molecular docking techniques should be employed to reveal the interaction mechanisms of pinocembrin glycoside with bacterial DNA gyrase (with a predicted binding energy to the GyrB subunit of ≤ −8.5 kcal/mol) and fatty acid synthase (FabI activity inhibition rate >80%).

Given that F. hirta is classified as both a medicinal and an edible resource, a critical future direction is to assess its bioavailability and pharmacokinetic profile. While in vitro and in vivo efficacy studies are promising, it remains largely unknown how well its bioactive compounds—such as flavonoids and phenolic glycosides—survive gastrointestinal digestion, cross intestinal barriers, and reach target tissues in active forms. Future studies should employ Caco-2 cell monolayer models, simulated gastrointestinal digestion systems, and animal pharmacokinetic trials to evaluate the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of its key constituents. This will bridge the gap between in vitro mechanisms and real-world therapeutic outcomes.

Furthermore, a systematic UPLC-QTOF-MS compositional profile of roots, leaves, and syconia should be established. Combined with macrophage polarization models, differences in the bioactivity of flavonoids (38% higher content in leaves) and terpenoids (enriched in roots) can be clarified to achieve comprehensive resource utilization [11].

An advanced approach for quality control involves constructing a fingerprint-efficacy correlation model using machine learning algorithms. Instead of relying on single-component quality control centered on psoralen, integrating metabolomics with machine learning could help identify the specific “chemical clusters”—combinations of flavonoids, phenolic acids, and polysaccharides—that are responsible for the plant's anti-inflammatory and antibacterial properties. Using high-resolution mass spectrometry, chemically characteristic peak clusters associated with specific efficacy should be identified to construct a holistic quality evaluation system. To address the intrinsic variability caused by geographical and environmental factors (e.g., the 15–20% variation in flavonoid content with altitude), we propose that future standardization of F. hirta extracts for clinical research should focus on a panel of bioactivity-linked marker compounds rather than a single component. Based on the molecular mechanisms summarized in Sections 4.1, 4.1.1, the following are recommended as priority markers: psoralen (a representative coumarin with antibacterial and anti-inflammatory activities), bergamottin (a key IKKβ inhibitor driving M2 macrophage polarization), pinocembrin glycoside (a flavonoid with antifungal membrane-disrupting activity), quercetin (a well-characterized antioxidant and anti-inflammatory flavonoid), and total phenolic content or a representative phenolic acid (e.g., vanillic acid or euonymifolioside B) to reflect the contribution of phenolic compounds. These markers can be quantified using validated HPLC or UPLC-MS methods, and their combined use, together with the fingerprint-efficacy model, will help overcome geographical variability and ensure consistent biological activity in future clinical studies. Multivariate numerical analysis methods (e.g., improved grey relational analysis or random forest regression) can then quantify the contribution of chemical component groups to efficacy, offering new data-driven strategies for screening active constituents.

Integrating chemical analysis with pharmacological research will advance the scientific construction of quality standards and promote efficient utilization of F. hirta resources.

9. Conclusion

F. hirta stands out as a potent reservoir of diverse bioactive metabolites with a demonstrated capacity to modulate complex molecular networks of inflammation and infection. As summarized in Fig. 3, the anti-inflammatory effects of F. hirta extracts are primarily achieved through the inhibition of the NF-κB and MAPK signaling pathways, leading to reduced release of pro-inflammatory cytokines (e.g., TNF-α, IL-1β, IL-6) and suppressed recruitment of inflammatory cells. This molecular cascade—centered on NF-κB inhibition—provides a mechanistic basis for the plant's therapeutic efficacy in inflammatory conditions. Concurrently, as illustrated in Fig. 4, the antibacterial and antifungal activities of F. hirta are attributed to the disruption of microbial cell wall/membrane integrity, interference with key metabolic enzymes (e.g., DNA gyrase, fatty acid synthase), and suppression of biofilm formation.

The true strength of F. hirta lies not in a single compound, but in the harmonious synergy between its multiple bioactive classes—including flavonoids, phenolic acids, terpenoids, and polysaccharides—that together address both the pathogen and the host's immune response simultaneously. This multi-target therapeutic approach is further supported by the immunomodulatory and antioxidant properties of the extracts, which synergize with their direct antibacterial and anti-inflammatory activities to enhance overall biological efficacy.

Notably, the dual role of F. hirta as both a medicinal and an edible resource positions it as a unique candidate for the development of nutraceuticals and preventive medicine strategies. Its established safety profile, combined with its multi-target molecular mechanisms, makes it particularly attractive for managing chronic inflammatory and infectious conditions where long-term intervention is required.

Despite the promising findings, current research still presents limitations, including a lack of systematic investigation into synergistic molecular interactions among compound classes (e.g., flavonoids and polysaccharides), insufficient pharmacokinetic and bioavailability studies, and an absence of clinical translational evidence. Addressing these gaps—particularly through the integration of machine learning-assisted fingerprint-efficacy modeling and rigorous bioavailability assessments—will further solidify the scientific foundation for the development and application of F. hirta extracts in pharmaceutical and food industries.

Funding

This work was supported by grants from:

National Natural Science Foundation of China [32300020] (W.W.)

Natural Science Foundation of Anhui Province [2023AH050735] [2024HZ072] (W.W.)

Guangdong Province Basic and Applied Basic Research Fund Project (No. 2022A1515110889) and Shenzhen Science and Technology Planning Project (Natural Science Foundation) (No.JCYJ20220530173013029 and JCYJ20220530173013030) (Y.A.)

CRediT authorship contribution statement

Yao Dong: Formal analysis, Investigation, Methodology, Writing – original draft. Yitong Li: Investigation, Methodology. Hengxiu Wang: Investigation. Hongchen Wang: Investigation, Methodology. Changzhong Wang: Supervision. Tianming Wang: Resources. Daqiang Wu: Resources. Yawen An: Funding acquisition, Investigation, Resources, Supervision. Caixia Zheng: Conceptualization, Project administration, Resources, Supervision. Wenfan Wei: Conceptualization, Formal analysis, Funding acquisition, Investigation, Project administration, Resources, Supervision, Writing – review & editing.

Declaration of competing interest

The author is an Editorial Board Member/Editor-in-Chief/Associate Editor/Guest Editor for this journal and was not involved in the editorial review or the decision to publish this article.

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Yao Dong, Yitong Li, Hengxiu Wang, Hongchen Wang, Changzhong Wang, Tianming Wang, Daqiang Wu, Yawen An, Caixia Zheng, Wenfan Wei.

Data availability

No data was used for the research described in the article.