Guava (Psidium guajava): A brief overview of its therapeutic and health potential

Abstract

Background

The guava (Psidium guajava) has long been valued for its variety of pharmacological characteristics. The plant has bioactive chemicals in its leaves, fruit, and bark, which enhance its potential for therapeutic use.

Objective

The goal of this review is to compile the most recent information on the pharmacological properties of guava, with an emphasis on its anti-inflammatory, anti-hypertensive, anti-obesity, antioxidant, antidiarrheal and antidiabetic properties as well as on its ability to treat dental diseases and increase haemoglobin levels in body.

Methods

To assess the potential health benefits derived from guava, a thorough review of it in vitro, and vivo clinical investigations was carried out.

Results

The main cause of guava's strong bioactivity is its flavonoids. Its application in the treatment of different diseases is supported by evidence. The medicinal potential of its inclusion in functional meals is encouraging.

Conclusion

The guava fruit has a wide range of therapeutic properties and is rich in nutrients. More human trials are needed to confirm efficacy, optimize dosage, and guarantee safety in long-term usage, even though preclinical research appears encouraging.

Graphical abstract

Highlights

• •Guava has been associated with better digestive, skin, and immunological health.
• •It is the best source of vitamin C and essential minerals such as iron and phosphorus.
• •Guava has long been valued for its variety of bioactive compounds.
• •These can prevent acetaminophen-induced liver damage by modifying oxidative stress pathways.

1. Introduction

Plants are among the most prominent candidates in herbal medicine (Abduallah, Ahmed, Bajaber and Alalwiat, 2023, Abduallah, Ahmed, Bajaber and Alalwiat, 2024; Rumiyati et al., 2024). Products of plants are easily available, cheap, and have the slightest tendency to develop resistance, due to which they could be proven beneficial for health (Ahmad et al., 2023; Rashid et al., 2024; Luecha et al., 2024). Herbal medicines are broadly used by the lower to middle classes to promote, prevent, and rehabilitate (Dalal et al., 2023). Plants have also been used as an alternative to antiparasitic drugs due to their pharmacological characteristics described in the recent past (Aljohani, 2024; Ghany et al., 2023; Hussain et al., 2023, Hussain et al., 2024; Mubarik et al., 2023). Knowledge about the usage of therapeutic plants is a custom that is continued from one generation to another. Level of education, ecological zone, and ethnicity are aspects that are associated with the knowledge and usage of medicinal plants (Andualem, 2023; Hegazy et al., 2023).

Approximately 80 % of the global population uses plants as traditional medicines. World Health Organization (WHO) claims that 11 % of drugs that are used for human health care are derived from plants. According to the Behaviour Change Communication research on the market, which was conducted in 2017, it was stated that the use of herbal products has been a reason for an increase in the global market up to 59.45 billion US dollars. This market is expected to rise to 104.78 billion US dollars in 2026 at an annual rate of 6.5 % (Bareetseng, 2022). Functional foods are also currently being used to provide health benefits beyond their nutritional value (Çalışkan and Emin, 2023).

Psidium guajava Linn. (Guava) is a notable medicinal plant with enormous pharmacological potential. It belongs to the following taxonomic categories: Myrtaceae family, Myrtoideae subfamily, Myrteae tribe, Magnoliophyta division, Magnoliopsida class, Rosidae subclass, Myrtales order, Psidium genus, and Guajava species. The botanical classification of guava is mentioned below in Fig. 1. Guava is a small shrub-like tree that can grow up to 10 m tall. Its fruit is round, oval, or pear-shaped, varying in size from 1 to 48 oz (Kafle et al., 2018). When ripe, guava emits a strong, sweet, and musky aroma. The outer peel can be either green or yellow, while the flesh comes in various colors, including white, yellow, pink and red. It also contains numerous small, hard and white seeds. Guava leaves are 1 to 2 in. wide with 2 to 6 in. length. They are dull-green rigid and are coriaceous with prominent veins (Jamieson et al., 2022). (See Fig. 2.)

Fig. 1.

Botanical Classification of Guava.

Fig. 2.

Therapeutic properties of guava.

In South America, guava plants were grown for the first time (Sudira et al., 2019). Guava is widely cultivated fruit in India, Pakistan, Bangladesh, Indonesia, South America, and other tropical and subtropical regions (Kumar et al., 2022; Rehman & Khan, 2022). Among the major guava producing nations, Pakistan ranks second in terms of production (Gangappa et al., 2022; Khan et al., 2020). In India, guava is cultured on 261.4 thousand hectares of land, production is around 3648.2 thousand metric ton and productivity is about 13.9 metric ton each hectare. Guava is grown on 11.64 thousand hectares of land in Gujarat and its production is roughly 153.04 thousand metric ton. It is grown on 12.49 thousand hectares of land in Maharashtra and production is about 140.86 thousand metric ton (Matholiya et al., 2020). When it comes to the production of fruit and food wastes, Brazil stands out since it produces 43.6 million tonnes of fruits annually. Oranges, bananas, and guavas account for 16.8 million tonnes, 7.1 million tonnes and 0.6 million tonnes of the nation's total agricultural production, respectively. As a result, these fruits are extremely important to the nation and produce a significant quantity of residue (Pereira et al., 2022). Mexico currently ranks fifth in the world with an annual production of 302,718 t (2017); a 5 % increase in harvested area is predicted to boost production, which is exported at a rate of 4 %, mostly to the United States and Canada. In terms of guava output worldwide, Pakistan comes in fourth (Angulo-López et al., 2021). The goal of this research is to emphasize the antioxidant, antihypertensive, antiobesity, antihyperlipidemic, and antidiabetic properties that make it a useful functional meal with potential health advantages.

2. Nutrients and phytochemicals in guava

Guava contains macro and micronutrients. It includes vitamins C, iron, phosphorus, and calcium. It offers more vitamin C than an orange. It also contains bioactive compounds such as saponin, oleanolic acid, quercetin, catechin, epicatechin, rutin and kaempferol (Lakshmi et al., 2022). Additionally, the roots include tannins, leucocyanidins, gallic acid, and sterols. To identify the chemical components, Gas Chromatography–Mass Spectrometry was used to hydro-distilate the P. guajava leaves that were obtained from Northeast India. The leaf essential oil contained a total of 27 components. Trans-Caryophyllene (17.65 %), nerolidol (12.16 %), α-terpinyl acetate (23.57 %), α-cadinol (6.71 %), and α-copaene (6.5 %) were the major chemicals, whereas α-humulene (3.92 %) and (−)-caryphyllene oxide (3.66 %) were the minor compounds (Uzzaman et al., 2018).

In the world, nowadays there is a trend of replacing allopathic drugs with organic food resources that have healing and therapeutic potential due to their bioactive components (Choudhary and Tahir, 2023). Organic foods that contain bioactive constituents serve as strong antioxidants and can protect the body against the bad effects of free radicals (Bebas et al., 2023; Gutierrez-Montiel et al., 2023). Table 1 explains about the bioactive components and nutritional composition of guava.

Table 1.

Bioactive components and nutritional composition of guava.

Components	Guava fruit g/100 g	Guava leaves g/100 g	References
Macronutrients			(Pawar et al., 2023; Thomas et al., 2017; Namrata et al., 2019, Babatola & Oboh, 2021).
Carbohydrates	14 g	38.23 g
Protein	2.6 g	22.29 g
Fat	0.5 g	5.05 g
Fiber	5.4 g	5.41 g
Vitamins
Vitamin C	200–400 mg
Minerals
Iron	0.26 mg	13.50 mg
Calcium	18 mg	1660 mg
Phosphorus	28 mg	360 mg
Bioactive components
Saponins	9.265 μg/mL	–
Alkaloids	12.982 μg/mL	–
Flavonoids	21.02 μg/mL	High
Chlorogenic Acid		149.79 mg
Rutin		123.90 mg
Quercetin		17.69 mg
Vanillic Acid		19.34 mg
Total Phenolic Compounds	94.06 mg	397.44 mg

The main bioactive substances in guava and their possible health advantages are broken down here. One terpenoid alcohol that has been shown to have anti-inflammatory and antioxidant qualities is α-terpineol. It might be advantageous for relaxation and respiratory health. β-Caryophyllene, also known as trans-caryophyllene, is a sesquiterpene that modulates cannabinoid receptors. It may find use in pain management and anxiety reduction therapies because to its analgesic and anti-inflammatory qualities. Rutin is a flavonoid that possesses antioxidant qualities. Its ability to promote blood vessel health and lower the risk of cardiovascular illnesses is well recognised. The anti-inflammatory and analgesic properties of α-humulene, another sesquiterpene, have been investigated. It might potentially be used as an anti-cancer drug and in the treatment of pain (Joshi et al., 2023).

The triterpene oleanolic acid (OA) has anti-inflammatory and antioxidant qualities. In addition to perhaps improving skin health, it might help shield the liver. Quercetin is a flavonoid that has anti-inflammatory and antioxidant properties. It has anti-allergic qualities and may help cardiovascular health. Guava contains flavonoids, a family of polyphenolic chemicals that are well-known for their anti-oxidant qualities. They might aid in lowering inflammation and oxidative stress in the body. Polyphenolic substances known as tannins have the potential to be both antioxidants and antimicrobials. They might be part of what makes guava fruit astringent. The protein known as lectins has the ability to attach itself to carbs. They might contribute to the immune system and possibly have anti-cancer properties (Ayeleso et al., 2017).

One polyphenol with antioxidant qualities is ellagic acid. In addition to supporting skin health, it may have anti-cancer properties. Plant sterol beta-sitosterol has the potential to improve prostate health and decrease cholesterol. Ursolic acid, oleanolic acid, and uvaol are triterpenes and have many possible health advantages such as anti-inflammatory and antioxidant qualities (Dakappa et al., 2013).

3. Health benefits of guava

Phenolic compounds contribute to the sensory characteristics of flowers, fruits, and vegetables. They also improve the color and flavor of various plant-based foods (Amna et al., 2023). The phenolic compounds of guava possess antioxidant, antidiarrheal, antimicrobial, antiobesity, antidiabetic, and antihypertensive activities (Prabhudesai et al., 2019; Sah et al., 2023). Fig. 1 explains about the therapeutic properties of guava.

3.1. Antidiabetic activity

Most of the global population is suffering from diabetes, which is one of the metabolic disorders. This disease arises because of the inadequate production of insulin from the cells of the pancreas. Guava leaves have been used as a therapeutic medicine widely for the management of diabetes (Luo et al., 2019). Guava has a lot of triterpenoids in its leaves, which in a study helped rats with diabetic peripheral neuropathy by lowering their insulin resistance (IR) in adipocytes. Higher leaf triterpenoid corosolic acid is a strong α-glucosidase inhibitor that slows down the metabolism of carbohydrates and lowers the postprandial blood glucose spike, both of which are helpful in the treatment of diabetes mellitus (DM). Additionally, the ethanol leaf extract has a preventive and antidiabetic effect on altered glucose metabolism, lowering HbA1c blood glucose levels and raising plasma insulin levels (Takeda et al., 2023).

When P. guajava leaf extracts are administered in vivo to diabetic rats caused by streptozotocin/alloxan, hyperglycemia was reduced by regulating glucose homeostasis and insulin sensitisation. The DPP4 inhibitors naringenin, (epi)-catechin, guavinoside C, and stachyuranin A were discovered. DPP4 inhibition would lengthen the half-life of the incretin hormones, which would enhance insulin secretion and give blood glucose levels more time to return to normal (Díaz-de-Cerio et al., 2023).

3.2. Antioxidant activity

Free radicals, which are formed as a result of metabolic processes, are the main reasons for diseases in human beings, such as ischemic heart disease, nervous disorders, and immune deficiency disorder (Luo et al., 2018). P. guajava fruit has been shown to have an antioxidant effect by restoring enzymatic antioxidants and inhibiting the activation of nuclear factor-kappa B (NF-kB). Guava fruits with pink pulp essence have been found to contain a high concentration of phenolic compounds and a considerable amount of carotenoids, particularly lycopene. These substances were mostly in charge of the antioxidant activity (Rishika & Sharma, 2012).

3.3. Anti-diarrheal activity

The treatment of children's diarrhea by utilizing guava leaves and other common traditional medicines was used as a first line of treatment for digestive disorders. Guava buds and leaves were used to extract quercetin and quercetin-3-arabinoside, which, at doses of 1.6 g/mL, demonstrated a painkiller-like suppression of neurotransmitter unharness within coaxially stirred-up the small intestine and caused a corresponding rise in muscle tone that gradually decreased. Additionally isolated from the leaves, asiatic acid exhibited dose-dependent (10–500 g/mL) spasmolytic action (Dange et al., 2020).

3.4. Antihypertensive activity

The key to lowering the risk of stroke and coronary heart disease is controlling excessive blood pressure. Numerous epidemiological studies suggest that the significant photochemical found in guava fruit may help avoid cardiovascular disease (Nath et al., 2023). Various guava leaf extracts have been shown to block glucose transport mediated by sodium-dependent glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2) both in vitro (Caco-2 cells) and in vivo (C57BL/6 N mice). Additionally according to some randomised, controlled trials, eating 500–1000 g of guava fruit per day can also lower blood pressure and lipoprotein levels without lowering high-density lipoprotein cholesterol (Singh et al., 2022). Quercetin, a member of the flavonoid family, is widely distributed in guava leaves along with other flavonoids. Through its inhibition of xanthine oxidase (XO) and restriction of RAAS, quercetin effectively lowers high blood pressure. Bradykinin was triggered by quercetin, which also prevented angiotensin 1-induced hypertension. Because it inhibits the RAAS, which dilates blood vessels and reduces blood pressure, the antioxidant quercetin exhibits anti-hypertensive qualities. Quercetin may also enhance endothelial function, which in turn generates NO, a vasodilator chemical (Ahmad et al., 2025).

3.5. Antiobesity activity

The α-amylase, glucosidase, and lipase enzymes that contribute to the development of obesity were inhibited by the leaf extracts of P. guajava, demonstrating strong anti-obesity action.

Pancreatic lipase inhibitory activity ranged from 19.25 to 38.51 % in the aqueous extract and from 22.96 to 46.66 % in the methanolic extract (Patil et al., 2024). Obesity also raises the risk of nephrolithiasis. The guava stem bark extract's capacity to inhibit the enzymes pancreatic lipase and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, which are linked to obesity, was thus examined. The extract's IC50 value of 21.66 ± 1.47 μg/mL was lower than that of the reference pancreatic lipase inhibitor orlistat (1.08 ± 0.03 μg/mL). By blocking pancreatic lipase, the guava bark extract may slow down the rate at which dietary lipids are broken down and subsequently absorbed as fatty acids, preventing overweight and obesity (Irondi, 2020).

3.6. Anticancer activity

The HT-29 cell line was used to test the anticancer properties of a guava branch acetone extract. After 24 h of incubation, the extract showed a dose-dependent suppression of cell vitality, reducing cell viability by 30–70 % in comparison to the control. With an IC50 value of less than 100 μg/mL, the guava branch extract prevented the cells from undergoing colony formation. A dose-dependent rise in the cells' lactate dehydrogenase (LDH) leakage, a sign of cellular damage, was also brought on by the extract. The assays for colony formation and lactate dehydrogenase release both demonstrate how lethal the extract is to colon cancer cells. Additionally, flow cytometry revealed that the cells treated with the guava branch extract had almost 30 times as many apoptotic cells in the sub-G1 phase as the control group. Through this it was concluded that acetone extract of the guava branch has considerable potential as a natural anticancer chemotherapeutic treatment for colon cancer (Lok et al., 2023).

3.7. Anti-inflammatory activity

Thymus generation and germ infection can be inhibited by guava leaves extract in ethyl acetate. It may function as an antiviral agent. It may increase the expression of mRNA. It can also change the function of the heme oxygenase-1 protein due to which it can be utilised as an anti-inflammatory agent for the skin. Guava leaves extract in ethanol prevents the production of nitric oxide by lipopolysaccharide. It inhibits the production of E2. This is how it also functions as an anti-inflammatory. The extract in ethyl acetate can reduce the amount of antigen. It can prevent the release of histamine and β-hexosaminidase into RBL-2H3 cells. This causes TNF-α and IL-4 mRNA to cease to emerge. Thus, IκB-α is spoilt and the antigen is inhibited. Guava leaves contain essential chemicals such flavonoids and benzophenone. These substances are in charge of nitric acid synthesis and histamine inhibition (Naseer et al., 2018).

3.8. Rise in haemoglobin

Iron is one of the essential minerals found in guava (0.6–1.4 mg/100 g). The right nutritional recommendation to cure and prevent anemia is to increase vitamin C intake. A quasi-experiment was performed in which 29 pregnant women receiving antenatal care (ANC) at the Kalasan community health center participated. The participants were split into two groups: the control group and the treatment group. For a duration of two weeks, each group received two doses of iron supplement therapy, and the treatment group additionally received 200 ml of guava juice daily. Results showed that vitamin C in guava fruit juice affects the production of red blood cells during bone development as well as the preservation of normal haemoglobin levels because guava juice stops red blood cell haemolysis due to which it can raise haemoglobin levels. Furthermore, due to the antioxidant qualities of red guava, guava juice can also stop the lipolysis process. Additionally, guavas have five times as much vitamin C as oranges. According to this study, pregnant women's haemoglobin levels were effectively raised by administering 200 ml of guava juice daily for two weeks (Wahyuntari & Wahtini, 2020).

3.9. Antibacterial activity

Mouthwashes containing guava leaves extract significantly decreased the number of Streptococcus mutans colonies after seven days of use. Flavonoids, polyphenols, and tannins are some of the bioactive substances considered to be responsible for the antibacterial properties of guava leaf extract. Flavonoids called guaijeverin and quercitin, which are present in guava leaves, form complexes with extracellular proteins, dissolve in bacterial cell walls, and interrupt the bacterial life cycle. Proline-rich proteins are bound by tannins, which are polyphenolic substances found in guava leaves. This inhibits protein synthesis and causes protein denaturation, which harms bacteria's metabolism. Additionally, they efficiently eliminate the bacterial cell by dissolving the fatty layer of the cell wall that allows cell fluid to escape (Kassem et al., 2022).

3.10. Safety and toxicology

Numerous research studies have assessed the guava's (P. guajava) safety and toxicology. Using methanolic and ethanolic extracts of guava leaves, acute toxicity testing revealed that dosages of up to 5000 mg/kg in rodents did not result in death, suggesting a high safety margin. Studies on chronic toxicity conducted over a period of 90 days showed that dosages up to 200 mg/kg/day were safe and did not significantly alter histological, hematological, or biochemical markers. Higher doses (400 mg/kg/day) were shown to cause liver toxicity, which included tissue destruction and elevated biomarkers. This suggests that long-term high-dose use may be dangerous (Igwe et al., 2021; Liu et al., 2024).

4. Review of studies of guava

The guava fruit, as well as its leaves can be used for various therapeutic properties (Aghababaei & Hadidi, 2023; Shabir et al., 2022). The purpose of this study is to provide a summary of the different therapeutic activities of guava against diverse health diseases. These studies are described below as well as in Table 2.

Table 2.

Therapeutic roles of guava in different studies.

Study	Subject	Treatment	Methodology	Outcome	Citation
Randomised, parallel clinical research	31 adults	Guava extract was given to examine the postprandial glucose response	Control group: glucose solution Intervention group: guava fruit extract (supercritical CO2 extract) combined with glucose solution. Blood samples taken before and up to two hours after consuming glucose. Blood glucose and insulin levels; oral glucose tolerance test (OGTT) was measured	At 30 and 90 min, the guava extract group's postprandial glucose increase was considerably lower (Δ 1.96 vs 2.60 mmol/L; p = 0.039 and Δ −0.18 vs 0.44 mmol/L, respectively; p = 0.023). A small but non-significant decrease in insulin secretion was seen (p = 0.302).	(König et al., 2019)
Randomised control trial	28 male Wistar rats (185–200 g) of age 10–12 weeks	Guava leaves powder containing (quercetin, gallic acid, catechin, rutin and epicatechin) was given to reduce induced hepatic steatosis and dyslipidemia in rats for 56 days	4 Groups (Gs): n = 7 Group 1 (G1): control group (CG) given normal diet Group 2 (G2): 2.5 % of guava leaf powder + normal diet was given Group 3 (G3): high carbohydrates and high fat (HCHF) diet was given starch Group 4 (G4): HCHF +2.5 % of guava leaf powder was given	Guava leaf powder reduced increased weight in HCHF diet-fed rats Normal rats treated with guava leaf powder also showed a reduction in liver weight compared to G1 Guava leaves powder also reduced aspartate transferase (AST), alanine transaminase (ALT), triglycerides, and total cholesterol levels in HCHF diet-fed rats	(Mamun et al., 2019).
A quasi-experimental study with a pre-test post-test control design.	39 diabetic adults aged 45–70 years with glycated haemoglobin (HbA1c) greater than 7 were taken	Red guava and papaya were given to reduce blood sugar levels after breakfast and lunch for 14 days	3 Gs (n = 13) G1: 282.2 g of red guava was given G2: 302.4 g of papaya was given G3: treated with mineral water as control	There was a significant reduction in blood glucose level after the administration of red guava (33 g/dl) and papaya (14 g/ dL) compared to the CG There were no significant variations (p > 0.05) between red guava and papaya.	(Ismawanti et al., 2020).
Vivo study	36 mature female Wistar rats, weighing (245 ± 5 g) of 2 months old were used	In obese rats, the impact of consuming a low-fat diet with a fruit puree (guava-strawberry, guava-blackberry, guava-soursop, or guava-passion fruit) was evaluated on weight loss, lipid profile, and liver enzyme activity was for 8 weeks	6 Gs n = 6 G1: Control group given normal diet G2: Obese group fed with standard diet G3: obese group fed standard diet with guava-strawberry puree G4: obese group fed standard diet with guava- blackberry puree G5: obese group fed standard diet with guava-soursoup puree G6: obese group fed standard diet with guava-passion fruit puree	A decrease in body weight (16–24 %), a control in plasma lipid metabolism, and a decrease in total cholesterol (59–68 %) and triacylglycerols (61–82 %) were linked to the greater consumption of fruit purees Enzyme activity (alanine aminotransaminase, aspartate aminotransferase, γ-glutamyl transferase, and alkaline phosphatase) decreased Liver morphology significantly improved and a significant drop in inflammation markers and liver damage was observed	(Morales-Ávila et al., 2020).
Vivo study	25 Wistar rats were randomly selected of weight 180–220 g	This study examines the potential of P. guajava stem-back aqueous extract as a curative antioxidant indexes in plasma, liver, kidney, heart and lungs homogenates in rats for 28 days	5 Gs (n = 5) Treatment starts 14 days after induction with 40 % ethanol and includes 20 mg/kg of vitamin C and an untreated control. GA: 50 mg/kg of P. guajava stem-back aqueous extract was given GB: 100 mg/kg of P. guajava stem-back aqueous extract was given GC:200 mg/kg of P. guajava stem-back aqueous extract was given to GD: given oral vitamin C at a dose of 20 mg/kg. GE: received oral administration of 2 mL/kg of 40 % ethanol	In-vivo antioxidant study of enzymatic and non-enzymatic antioxidant elicited a significant increase in Superoxide dismutase of plasma and tissue homogenates across the tested groups with the highest significant values at (4.93;4.07; 2.41; 4.63; 3.51 U/mL) Reduced glutathione at (4.58; 2.60; 2.49; 4.37; 2.69 U/mL), catalase at (289.87; 126.00; 126.97; 244.28;121.94 U/mL), glutathione peroxidase (1.97; 2.10; 2.26; 2.06; 2.04 U/mL) when compared with untreated control (p < 0.05) with decreased in the level of MDA at (18.74; 16.02; 15.81; 17.78; 14.33 U/mL) when compared with untreated control at (32.01; 35.17; 29.74; 31.85; 29.75 U/mL) of antioxidant indexes in plasma, liver, kidney, heart and lungs homogenates thereby scavenging or eliminating free radicals when compared with untreated control and vitamin C control P. guajava antioxidant scavenging ability produced neuroprotective, hepatoprotective, and bio-protective effects on visceral organs	(Gabriel et al., 2021).
Vivo study	21 days old Wistar male rats	Ethanol extract of guava leaves containing (quercetin, tannins, and gallic acid) was given to induced hypertensive rats for 16 weeks duration	2 Gs were made G1: Standard salt diet (SSD) received (0.27 % sodium w/w) after weaning G2: High salt diet (HSD) received (0.90 % sodium w/w) after weaning Ethanolic quercetin extract of guava leaves in the dose of (100 mg/kg or 200 mg/kg) or vehicle by orogastric gavage, in a volume of 1 mL, once a day, and for 4 more weeks after 12 weeks was given	Food intake and sodium balance were not different in SSD and HSD Gs even after being treated with ethanolic quercetin extract from guava leaves Water balance was increased in HSD rats which was decreased with 100 mg/kg ethanolic quercetin extract from guava leaves HSD rats treated with 200 mg/kg ethanolic quercetin guava leaf extract showed a reduction in blood pressure compared to those treated with vehicle Greater reduction in blood pressure was observed in HSD rats as compared to SSD rats Only treatment with 100 mg/kg ethanolic quercetin extract of guava leaves was able to decrease blood pressure in HSD diets compared to the vehicle control group	(de Assis Braga et al., 2022).
Vitro study	Articular chondrocytes from 10 Chinese patients with knee osteoarthritis	Psidium guajava hydroalcoholic extract's anti-inflammatory effects on knee osteoarthritis gene expression	G1: control cartilage cells with no treatment G2: healthy cells treat with guava extract G3: Inflammatory Control: Osteoarthritic chondrocytes + LPS (20 ng/mL G4: Osteoarthritic chondrocytes + LPS (20 ng/mL) + Guava extract G5: Osteoarthritic chondrocytes + LPS (20 ng/mL) + Phosphate-Buffered Saline (PBS) G6: Osteoarthritic chondrocytes + LPS (20 ng/mL) + Dexamethasone G7: Osteoarthritic chondrocytes + LPS (20 ng/mL) + Naproxen	TNF-α was down 51.86 % and resistin was down 56.59 %, which is similar to the effects of naproxen and dexamethasone.	(Wu, 2021).
Single-blind, randomised study	145 hypertensive individuals	Guava fruit was given daily	0.5–1.0 kg of guava per day for 4 weeks	Blood pressure decreased by 7.5/8.5 mmHg; triglycerides reduced by 7.0 %; total cholesterol reduced by 7.9 %	(Dinda & Purwanata, 2023).
Randomised control trial	60 adult male Wistar rats (150–200 g)	Quercetin in the form of methanolic extract from guava leaves was given to induced diabetic rats for 6 weeks	4 Gs (n = 15) G1: CG given 50 mg/kg methanolic quercetin guava leaves extract All other 3 Gs: diabetic control group (DCG) given 100 mg/kg of quercetin	After the experimental period it was observed that blood glucose levels decreased in diabetic rats Triglycerides, low-density lipoprotein, and total serum cholesterol levels were also reduced in diabetic rats	(Abdel-Tawab et al., 2023)
Randomised control study	60 individuals with aggressive localized periodontitis were selected	Gel made from guava (P. guajava) leaves was considered a potential option for treating periodontal disease for 6 months	2Gs (n = 30) G1: received guava leaf gel as part of the intervention CG: placebo gel as part of the control. Root planing (SRP) and scaling were performed on both groups. At baseline and six months, clinical parameters were measured, such as the plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL).	In comparison to the placebo group (PI: 2.65 ± 0.33 to 1.82 ± 0.29, GI: 2.88 ± 0.29 to 1.80 ± 0.25, BOP: 86.00 % to 30.80 %, PPD: 6.15 ± 0.35 mm to 4.20 ± 0.33 mm, CAL: 5.80 ± 0.30 mm to 3.85 ± 0.30 mm), the guava leaf gel group demonstrated significant reductions in PI (2.85 ± 0.35 mm to 2.90 ± 0.28 mm), GI (2.90 ± 0.34 to 1.50 ± 0.20), and BOP (87.50 % to 23.60 %) at the 6-month follow-up Comparing the guava leaf gel group to the placebo, all clinical metrics showed statistically significant improvements (p < 0.05)	(Kedia et al., 2024).
Quasi experiment design	30 expectant mothers of 1st and 3rd trimester with anemia were selected as samples	The purpose of this study was to ascertain how red guava juice drinking affected haemoglobin levels in pregnant women	2 Gs: pretest and posttest approach CG: Fe Tablets were given alone and Intervention Group (IG): Red Guava Juice with Fe Tablets were given	Prior to the delivery of Fe tablets, the control group's average haemoglobin level was 9.80 g per deciliter; following pill ingestion, it was 10.45 g per deciliter. Prior to receiving Fe tablets and red guava juice, the intervention group's average haemoglobin level was 9.64 g per deciliter; following ingestion of Fe tablets and red guava juice, it was 11.37 g per deciliter. The results of the statistical test showed a p value of 0.000. Pregnant women's haemoglobin levels are impacted by red guava juice consumption. To raise haemoglobin levels, pregnant women are advised to take Fe pills on a regular basis with red guava juice.	(Azizah et al., 2024).

Guava fruit extract, (a supercritical CO₂ extract), was given to 31 people in a randomised, parallel clinical research to assess its impact on postprandial glucose response. Prior to and for up to two hours following glucose consumption, blood glucose and insulin levels were assessed. The guava extract group demonstrated a substantially lower postprandial glucose increase after 30 min (Δ 1.96 vs 2.60 mmol/L; p = 0.039) and 90 min (Δ −0.18 vs 0.44 mmol/L; p = 0.023) in comparison to the control group. Additionally, there was a non-significant drop in insulin secretion (p = 0.302) (König et al., 2019).

In another study, effects of guava leaf powder (which contains quercetin, gallic acid, catechin, rutin, and epicatechin) on hepatic steatosis and dyslipidaemia were investigated in a randomised control experiment involving 28 male Wistar rats. The rats received 56 days of treatment after being split up into four groups. The guava leaf powder decreased liver weight in normal rats and decreased weight gain in rats given a high-carbohydrate, high-fat (HCHF) diet. Additionally, it decreased the triglycerides, total cholesterol, AST, and ALT levels in the rats fed HCHF (Mamun et al., 2019).

In a quasi-experimental study perofrmed by Ismawanti et al. (2020), 39 persons with diabetes, ages 45 to 70 participated to assess the effects of eating papaya and red guava on postprandial blood glucose. The participants were divided into three groups and given either mineral water, papaya, or red guava for a period of 14 days. Although there were no discernible differences between the two fruits, both significantly decreased blood glucose levels (red guava by 33 g/dL and papaya by 14 g/dL).

The impact of different guava-based fruit purees (such as strawberry, blackberry, soursop, and passion fruit combinations) on obesity-related parameters was evaluated for over 8-week period in a vivo study including 36 mature female Wistar rats. Rats fed the purees showed significant reductions in total cholesterol (59–68 %) and triacylglycerols (61–82 %), as well as better liver enzyme activity and a 16–24 % drop in body weight was also observed. Additionally, there was a notable improvement in liver morphology and inflammation indicators (Morales-Ávila et al., 2020).

The antioxidant capacity of P. guajava stem-back aqueous extract was examined in vivo study using 25 Wistar rats. Antioxidant enzymes such as glutathione peroxidase, reduced glutathione, catalase, and superoxide dismutase significantly increased in rats given different doses of the extract over the course of 28 days. Oxidative stress was indicated by a substantial decrease in malondialdehyde (MDA) levels. According to Gabriel et al. (2021), the extract exhibited neuroprotective, hepatoprotective, and overall bio-protective properties.

In another study guava leaf ethanol extract, which is high in quercetin, tannins, and gallic acid, was given to 21-day-old Wistar male rats for 16 weeks to evaluate its antihypertensive effects. The extract decreased water retention and blood pressure in rats fed a high-salinity diet. While the 200 mg/kg dose markedly decreased blood pressure, particularly in groups following high-salt diets, the 100 mg/kg dose decreased water balance (de Assis Braga et al., 2022).

Ten Chinese patients with osteoarthritis in their knees had their articular chondrocytes used in a vitro investigation to evaluate the anti-inflammatory qualities of P. guajava hydroalcoholic extract. The extract shown benefits similar to those of anti-inflammatory medications such as naproxen and dexamethasone, reducing resistin by 56.59 % and TNF-α by 51.86 % (Wu, 2021).

In a single-blind, randomised research with 145 hypertension participants, consuming 0.5–1.0 kg of guava fruit daily for four weeks resulted in significant decreases in total cholesterol (by 7.9 %), triglycerides (by 7.0 %), and blood pressure (by 7.5/8.5 mmHg) (Dinda & Purwanata, 2023).

The effects of methanolic guava leaf extract (including quercetin) on diabetic rats were assessed over a 6-week period in a randomised control experiment involving 60 adults male Wistar rats. When compared to untreated diabetic controls, treated rats displayed decreases in blood glucose, triglycerides, LDL, and total serum cholesterol (Abdel-Tawab et al., 2023).

In another study guava leaf gel was examined as a treatment for aggressive localized periodontitis in 60 participants over a 6-month period in a randomised control study. Clinical oral health metrics such as plaque index, gingival index, bleeding on probing, probing pocket depth, and clinical attachment level significantly improved in the guava gel group when compared to a placebo group (Kedia et al., 2024).

In a quasi-experimental study evaluated the effect of red guava juice and iron tablets on haemoglobin levels in 30 pregnant women with anemia who were in their first and third trimesters. With a statistically significant outcome (p = 0.000), the group that received both iron and red guava juice had a higher increase in haemoglobin (from 9.64 to 11.37 g/dL) than the group that received iron alone (from 9.80 to 10.45 g/dL) (Azizah et al., 2024).

5. Traditional medical applications of guava

Guava is a plant that is grown all over the world. It is an important resource in both traditional medicine and modern nutrition because of its many nutritional and medicinal qualities, which extend beyond its pleasant flavor and aroma. The leaves, bark and fruit of the guava plant have all been used in traditional medicine to cure a wide range of illnesses. Guava consumption has been associated with better digestive, skin, and immunological health. It is also a great option for people who want to control their blood sugar levels and encourage weight loss because of its high fiber content and low glycemic index (Sivakumar, 2024).

6. Applications of guava in functional foods

A variety of health benefits are provided by the several bioactive chemicals found in P. guajava (guava), such as flavonoids and polyphenols. These compounds make the plant a highly prized ingredient in functional foods and medications. Its extracts have strong antidiarrheal, antihyperglycemic and antioxidant qualities. Guava's bioactive compounds have been demonstrated to prevent acetaminophen-induced liver damage by modifying oxidative stress pathways. Furthermore, guava's bioactive compounds, quercetin and catechins, for example, make it a flexible component of functional foods intended to enhance lipid metabolism, control blood sugar, and strengthen immunity. These characteristics highlight the great potential of guava in creating foods that promote health and in creating pharmaceutical products (Kumar et al., 2021).

7. Conclusion

Guava is a tropical fruit well-known for its rich composition of bioactive components that contribute to its various health benefits. It is the best source of vitamin C and essential minerals such as iron and phosphorus. It is valuable, boasting anti-inflammatory, anti-hypertensive, anti-obesity, antioxidant, antidiarrheal and antidiabetic properties due to its high levels of flavonoids, making it a versatile functional food. Future studies should concentrate on more clinical trials to develop a standardized dosage and formulations for therapeutic use, even in light of these encouraging results.

CRediT authorship contribution statement

Eman Butt: Writing – review & editing, Writing – original draft, Conceptualization. Ammar B. Altemimi: Writing – review & editing. Aqsa Younas: Writing – review & editing. Masood Sadiq Butt: Writing – review & editing, Supervision. Maryam Jalal: Writing – review & editing. Maham Bhatty: Writing – review & editing. Gholamreza Abdi: Writing – review & editing. Rana Muhammad Aadil: Conceptualization, Writing – review & editing, Supervision.

Funding

The authors declare no financial support.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary data

Supplementary material

Data availability

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