Fruit vinegar as a promising source of natural anti-inflammatory agents: an up-to-date review

Abstract

Objectives

Fruit vinegar is one of the most famous fruit byproducts worldwide with several unique properties. There are two types of fruit vinegar, artisanal and industrial, for consumers to choose from. This review aims to assess for the first time the phytochemistry of fruit vinegar and its anti-inflammatory effects.

Method

The present work was conducted based on a literature search that selected the relevant papers from indexed databases such as Scopus, Science Direct, MDPI, PubMed, Hindawi, and Web of Science. We used numerous terms to assure a good search in different databases, including fruit vinegar, phytochemistry, bioavailability and bioaccessibility, and anti-inflammatory effect. All articles were selected based on their relevance, quality, and problematic treatment.

Results

Literature data have shown that vinegar has a long medicinal history and has been widely used by different civilizations, due to its richness in bioactive molecules, vinegar plays an important role in the prevention and treatment of various inflammatory diseases, including atopic dermatitis, mastitis, asthma, arthritis, acute pancreatitis, and colitis. Fruit vinegar consumption benefit is highly dependent on its chemical composition, especially organic acids and antioxidants, which can act as nutraceuticals.

Conclusion

Fruit vinegar has a rich chemical composition, including organic acids that can be transformed in the digestive system into compounds that play an important role in health-promoting features such as anti-inflammatory effects throughout the control of intestinal microbiota and pro-inflammatory cytokine production.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40199-023-00493-9.

Introduction

Fruit vinegar is a successful and diverse fruit-byproduct distributed worldwide and used by different civilizations across the world. It is very difficult to determine the exact time of its first use but it appears in several ancient writings in early times as a natural medication for several diseases [1]. Formally, the emergence of vinegar accompanied the discovery of fermentation from fruits and other sugar sources [2]. On the basis of the long medical history of this popular product, several experimental studies have been conducted to confirm its medicinal uses such as antidiabetic effect [3], neuroprotective effect [4], hepatoprotective effect [5, 6], anticancer effect [7], cardioprotective effect [8, 9], immunomodulatory effect [10], osteoprotective effect [11], and anti-inflammatory effect [12, 13]. Fruit vinegar consumption is beneficial for both animal and human health-related to its dense chemical composition [14]. Fruit vinegar is an excellent natural source of bio-valuable molecules, including phenolic compounds, flavonoids, tannins, melanoidins, tetramethylpyrazine, organic acids, and vitamins [15]. These molecules act their tremendous properties throughout pleiotropy effects. The bioactive compounds of fruit vinegar act as preventive agents against peroxidation of DNA, proteins, and lipids, which plays an important role in aging, cell proliferation, neurodegenerative disorders, and failure of the antioxidant defense system [16, 17]. Importantly, the chemical complexity of vinegar boosts the antioxidant defense system to attenuate the deleterious effects of toxic agents and reactive oxygen species (ROS) [18]. ROS disrupt various physiological activities in humans and induce different disorders such as inflammation throughout the activation of tissue tumor necrosis factor (TNF-α) and liberation of proinflammatory mediators [19]. Growing evidence has shown that the administration of fruit vinegar ameliorates intestinal permeability and controls intestinal microbiota, thereby inhibiting the entry of harmful molecules into the blood stream and controlling the inflammation process [12, 20, 21]. Additionally, numerous studies have shown that the consumption of fruit vinegar controls the production of proinflammatory cytokines [8, 10, 12, 16, 20].

The wicker in the history of fruit vinegar assures us that this product is widely used in folk medicine dating back to antiquity. The Egyptians were probably the first to discover and use vinegar under the name of Hmd or Hemedj [2]. The Babylonians used vinegar as a condiment and preservative. In Muslim culture, the meaning of vinegar has been established according to the Hadith narrated by Aisha ‘May Allah be pleased with her’ may the Prophet, may the peace and blessing of God be upon him, said ‘’The best of condiment is vinegar’’ [22]. He also said (Blessing and peace of Allah be upon him)’’ may Allah most high bless the vinegar because it was the sauce of the prophets before me’’ as reported by Ibn Madja (3318) and Dhaif al-Jami (5973). In his book called ‘’ Al-Quanon fi Tibb’’, the law of medicine’’ by Ibn Sina or Avicenna (980–1037) also mentioned the following properties of vinegar: coagulation, soothing headaches, expectorant, and healing of burns and skin inflammation [2].

To the best of our knowledge, there is no article review that summarizes and discusses the capacity of fruit vinegar to manage and regulate inflammatory disorders. Therefore, the main objective of the current review was to summarize the overview of fruit vinegar, including phytochemistry, bioavailability, bioaccessibility, and anti-inflammatory effects, to acquire a better understanding of the potential anti-inflammatory abilities of fruit vinegar.

Methodology

The present work was conducted based on the literature search that selected the relevant papers available in indexed databases such as Scopus, Science Direct, MDPI, PubMed, Hindawi, and Web of Science. We used numerous terms to assure a good search in different databases used including fruit vinegar, phytochemistry, bioavailability and bioaccessibility, and anti-inflammatory effect. All articles were selected based on their relevance, quality, and problematic treatment.

The studies used to create the current study were chosen on the basis of their relevancy, including scientific literature that alluded to the phytochemistry and anti-inflammatory characteristics of fruit vinegar. Other studies on the biological characteristics of fruit vinegar were excluded. The study’s search was limited to articles published exclusively in English.

Phytochemistry of fruit vinegar

Fruit vinegar is a very popular product with different chemical and aroma profiles [15]. The separation and purification of chemicals are performed using different techniques, such as gas chromatography, high-performance liquid chromatography, paper chromatography, thin-layer chromatography, ion exchange chromatography, gel permeation chromatography, affinity chromatography, and mass spectrometry [23]. A wide range of bioactive compounds are detected in fruit vinegars, including phenolic acids, flavonoids, melanoidins, tetramethylpyrazine, and organic acids. The phytochemistry profile of fruit vinegar is highly related to the nature of raw materials, fermentation method, microorganisms, fermentation time, and aging [24]. High amounts of polyphenolics are present in fruit vinegar varying between 252.90 ± 3.90 and 681.73 ± 14.55 mg GAE/L for grape vinegar, 119.16 ± 1.66 mg GAE/100mL for cherry vinegar; 100 ± 8.41 mg GAE/100 mL for peach vinegar, 106.91 ± 1.64 mg GAE/100mL for apple vinegar, 99 ± 2 mg GAE/100mL for raspberry vinegar, 124 ± 5 mg GAE/100mL for blueberry vinegar, 170 ± 8 mg GAE/100mL for blackberry vinegar, 2020 ± 24 mg GAE/100mL for rose hip vinegar, and 44 ± 2 mg GAE/100mL for persimmon vinegar [25–27]. These molecules are represented by transferulic acid for apple and cherry vinegars (43.921% and 29.88%, respectively) [25, 28], arbutin (77.16%) for cherry vinegar [25]. The determination of the phenolic profile of three types of fruit vinegar (Cherries vinegar, peaches vinegar, and apples vinegar) available on the market revealed 43 compounds with an abundance of arbutin, transferulic acid, apigenin, and ferulic acid [25]. Other researchers found that chlorogenic acid, gallic acid, catechin, and caffeic acid were the most abundant molecules in apple vinegar and pomegranate vinegar [29], whereas in persimmon vinegar and kiwifruit vinegar, gallic acid was the most active component found at high amounts [30]. The fermentation process of different raw materials used to produce vinegar affects the phenolic profile of the end product, it enhances the release of bioactive compounds, and the microorganisms involved in the process participate in the conversion of these chemicals into more active compounds, including organic acids, melanoidins, and tetramethylpyrazine [27]. Organic acids are also other types of bioactive compounds associated with health benefits against many diseases [31]. They control the vinegar aromas and can be found naturally or newly synthesized during vinegar manufacturing [32]. Acetic acid is the major component found in all kinds of fruit vinegar with proportions of 92.64 and 93.22% (29, 55). Liu et al. detected tartaric acid, malic acid, lactic acid, and succinic acid in apple, red wine, white wine, and balsamic vinegars [33].

Melanoidins are other bioactive compounds found in vinegar that play an important role in the determination of vinegar flavor [34]. In a study conducted by Liu et al. that the concentration of melanoidins in Zhenjiang aromatic vinegar ranged from 19.27 ± 20.57 to 22.57 ± 20.45 mg/mL [34]. These compounds exhibited considerable antioxidant abilities, as previously determined using ABTS and FRAP assays. The obtained values are expressed as follows: 2750.3 ± 65.2 and 1286.2 ± 679.9 mg Vitamin C/kg of balsamic vinegar, respectively [35]. Other active compounds, such as phenolic compounds, can link to melanoidins, forming complex molecules with high antioxidant potential [35].

The amounts of tetramethylpyrazine found in 36 fruit vinegar samples ranged from 0.113 ± 0.001 to 131.108 ± 1.966 mg/kg [36]. Wu et al. found that the quantity of tetramethylpyrazine detected in 9 kinds of fruit vinegar varied between 2.87 and 29.04 mg/L [37].

Bioavailability of bioactive compounds from fruit vinegar

The bioavailability of active ingredients is a critical factor in predicting their related-health benefits. It refers to the capacity of these compounds to pass through various barriers and enter the circulatory system [38, 39]. Bioactive compounds are distributed throughout the whole body via the circulatory system to act on specific targets [39]. Bakir et al. demonstrated that the in vitro digestion using pancreatin-bile salts mxiture had a significant impact on phytochemical composition of both investigated samples (grape and apple vinegars) [40]. In addition, it has been proven that the matrix limited the effect on phytocompound bioaccessibility in vitro [40]. Previously, numerous studies documented that the presence of such components accounting for citric acid and glucose strongly affects the passage of bioactive compounds over intestinal barriers [41, 42].

Mounting scientific evidence showed that the amounts of three active compounds including chlorogenic acid, caffeic acid, and quinic acid, decrease across the digestive tract and circulatory system. It was found that the amounts of molecules under study decreased significantly in plasma and urine. The bioavailability of chlorogenic acid depends on its metabolism by the gut microbiota [43]. A published study by Kishida and Matsumoto, reported that caffeic acid, p-coumaric acid, and ferulic acid are more highly predisposed to penetrate intestinal barriers than chlorogenic acid [44]. The study of the bioavailability of bioactive compounds is limited by the impracticality and ethical issues required to conduct further scientific research in vivo. For this reason, the scientific community concentrates its attention on the bioaccessibility of bioactive compounds, which is considered a key factor that controls their bioactivity [45–47]. Solid knowledge of the digestive fate of active ingredients of different vegetal matrices could be a key step in promoting health and ameliorating performance. Understanding gut-microbiota interactions with bioactive compounds of fruit vinegar could provide scientific insights into the beneficial properties of the active ingredient in question [20]. The fermentation process of fruits enhances the breaking of the vegetal matrix to release its bioactive food compounds and subsequently improves the bioaccessibility of the molecules in question [48]. The transformation of active ingredients found in esters, glycosides, or polymer forms could be a key factor in elevating the bioaccessibility of these compounds, thereby improving gastrointestinal absorption [49]. Vinegar’s chemical composition is enriched during manufacturing and aging processes, which increases the release of bioactive compounds from the raw material, thereby elevating their bioaccessibility [50, 51].

Management of inflammatory diseases by fruit vinegar

Non-pharmacological intervention using natural products and their derivatives plays an important role in the prevention and even treatment of various diseases. Recently, one of the most interesting products that has gained huge interest due to its important health benefits is fruit vinegar. Consumption of this product regularly furnishes a wide range of beneficial properties scientifically confirmed, including antidiabetic, antioxidant, cholesterol and weight lowering, immune boosting, anticancer, and antimicrobial activities [10, 35, 52–54]. Its ability to act positively and impact inflammation makes it a good candidate product for reducing the amounts of inflammatory cytokines [10, 55, 56]. Numerous studies on animal models have confirmed its potential to ameliorate inflammation by modulating the intestinal flora [12]. The intestinal microflora constitutes an effective therapeutic target for inflammatory diseases. This imbalance induces the down-expression of claudin-1, ZO-1, and occludin in gut acid secretion, which promotes intestinal permeability and facilitates the entry of toxic agents into the general circulation [57, 58]. Toxic agents activate tissue tumor necrosis factor (TNF-α) and promote the liberation of pro-inflammatory cytokines [19]. A diet enriched with fermented foods such as fruit vinegar enhances the potential probiotic effect and bioavailability of nutrients, produces antioxidants and functional ingredients, modulates intestinal flora, and controls the immune system [59]. Vinegar contains notable amounts of living and functional microorganisms and lipopolysaccharides (LPS) generated during the vinegar aging process [60, 61]. These molecules modulate macrophage function to regulate allergy, cancer, and inflammation by boosting the phagocytic effect and reinforcing the immune system [52, 61]. Mounting scientific evidence confirms that the administration of nipa vinegar affects gut microbiota, increasing Verrucomicrobia and Proteobacteriaphylum populations, controversially, decreasing the gut Firmicutes/Bacteroidetes ratio [55]. The same findings were evoked by Han et al. after consuming a fermented Korean food named Kimchi [62]. The gut microbiota of a healthy person is characterized by the abundance of beneficial bacterial genera, including Bacteroides, Lactobacillus, Akkermansia, and Parabacteroides, whereas the lowest Blauti and Allobaculum were found in the lowest quantities [62, 63]. The presence of mucin-degrading Akkermansia is negatively correlated with the inflammatory process [64]. Fruit vinegar-derived bioactive compounds are components naturally found in raw matter or newly synthesized and secreted during the vinegar manufacturing process [65]. These active ingredients feature various chemicals, including phenolic compounds, flavonoids, tannins, organic acids, melanoidins, and tetramethylpyrazine [66]. Previous reports have shown that the organic acids of vinegars regulate the intestinal flora by controlling the digestive pH, boosting pancreatic activity, and exerting a trophic effect on the innermost layer of the gastrointestinal tract [67]. In addition, organic acids inhibit the attachment and colonization of pathogenic and invasive microorganisms [68], and ameliorate intestinal morphology and barrier function [69]. A study conducted by Jiang et al. found that treatment with vinegar improved detachment of lamina propia of the intestinal mucosa, inflammatory cell infiltration in the intestinal wall decreases p65 and ICAM-1 expression, and increased E-cadherin in the intestinal tract of rats intoxicated by Euphorbia kansui [70]. Furthermore, the regulation of the intestinal microbiota improves the production process of short-chain fatty acids (SCFA) implicated in the control of the inflammatory processes involved in numerous diseases [71]. The abundance of SCFA has a profound influence on human health throughout the upkeep of the gut-barrier task. This beneficial property has been supported by experimental evidence showing that both SCFA accounting for butyrate and propionate induce the differentiation of T-regulatory cells, which is implicated in the control of intestinal inflammation by inhibiting histone deacetylation [72, 73]. SCFA have an important protective effect against high-fat diet-induced metabolic disorders via AMP-activated protein kinase [74], or mitogen-activated protein kinase [75]. Mounting scientific evidence has shown that the consumption of fruit vinegar regularly reduces the inflammatory cytokines, cyclooxygenase (COX)-2, nitric oxide (NO), inducible nitric oxide synthase (iNOS), and mitogen-activated protein kinase (MAPKs) (Fig. 1) [56, 76–78].

Fig. 1.

Beneficial effects of fruit vinegar and possible mechanism of action involved

Atopic dermatitis

Atopic dermatitis (AD) is a skin disorder affects approximately 20% and 6% of children and adults, respectively [79]. It is characterized by the modification of skin properties, which leads to the development of bacterial infections, particularly Staphylococcus aureus [80]. This change reduces the filaggrin production process and plays an important role in epidermal acidification [81, 82]. The control of skin pH is the most common approach to restore skin equilibrium and eradicate the pathogenic microbes that are involved in AD-like S. aureus [83]. Acidifier baths using dilute bleach are employed as a therapy for AD with promising results because of their ability to destroy pathogenic microbes [84]. Bleach’s treatment is a pH standpoint strategy to handle Staphylococcus aureus, showing an effective effect compared with water baths alone [85]. However, the effectiveness and safety of bleach baths have been called into question because of their side effects [86]. The required concentration of sodium hypochlorite (0.03%) to annihilate S. aureus is considered toxic to human cells [87, 88]. Among natural remedies, vinegar appears to be a prominent natural product with double benefits, acidifier, and sanitizer [89]. The study conducted by Luu et al. showed that the treatment of patients with dilute apple cider vinegar at a dose of 0.5% acetic acid, has no significant impact on the skin barrier integrity, despite a decreasing tendency of pH and an increasing tendency of transepidermal water loss [83, 90]. In contrast, oak wood vinegar (OWV) showed an effective anti-inflammatory effect on 2,4-dinitrochlorobenzene-induced contact dermatitis in an animal model. It was also revealed that OWV suppressed IgE production, iNOS expression, and immune cell infiltration throughout STAT3 inactivation [78]. The treatment of Oxazolone-intoxicated mice ((Ox)-AD) with acidic vinegar creams reduced AD-like lesions, lowered eczema scores, and transepidermal water loss (TEWL), while the treatment significantly increased stratum corneum hydration compared with the control group [91]. Within this framework, there are conflicting scientific facts about the use of vinegar as a natural remedy for atopic dermatitis, but it could be a departure point for conducting deep experimental research comparing different types of fruit vinegars well known for their pleiotropic action.

Mastitis

Mastitis is a mammary gland disorder involving inflammation. Mastitis-causing agents can be classified into major and minor pathogens [92]. Chemical germicide agents used to treat mastitis have numerous side effects, including milk contamination [92]. The search for safe and effective natural agents constitutes the main objective of the new scientific trend of using natural products. An ethnoveterinary survey conducted in Turkey to catalog traditional knowledge of herbal medicinal use documented that numerous medicinal plants were used in treating mastitis and improving milk production, including Urtica dioica L. MK-105, Smilax excelsa L. MK-1459, Acer heldreichii subsp. trautvetteri (Medw.) A.E. Murray MK-1044, Prunus laurocerasus L. MK-1193, and Bellis perennis L. MK-1179 [93]. Fruit vinegar is a natural remedy with multifaceted properties that could be useful for treating mastitis. The examination of the ability of acetic acid on mastitis pathogens showed interesting results compared with other acids such as lactic, lauric, and caprylic acids [92]. Acetic acid is the main organic acid of vinegar that is scientifically proven to exhibit strong antimicrobial effects against pathogens with high-antibiotic resistance [94–96]. It has been noteworthy to be noted that the main microorganisms implicated in mastitis, including Escherichia coli, Streptococcus uberis, and Staphylococcus, were highly sensitive to the effects of fruit vinegar, as previously confirmed by numerous published reports [97, 98]. Further investigations are required to evaluate the impact of fruit vinegar on mastitis.

Asthma

Asthma is a chronic disease in which inflammation plays a central role. The symptoms of asthma include wheezing, cough, and short breath [99]. Bronchodilators and anti-inflammatory medication are the most conventional treatments prescribed to treat asthma [70]. However, long-term and high doses limit their use because of the considerable side effects that appear during or after treatment [100]. The search for safe and effective compounds has redirected the interest of the scientific community toward natural products as a promising source of active ingredients, with fewer or non-adverse effects, that have proved their efficacy for treating asthma [101]. The dramatic increase in the use of fermented food to treat asthma has been noted [102]. Fruit vinegar is one of the most popular fermented foods widely used in traditional medicine [31]. The consumption of vinegar attenuated several effects of toxic agents such as hypercaloric diet, nicotine, hydrogen peroxide, high-fat-diet, phenylhydrazine, and so on [8, 54, 56, 103]. In addition, the application of vinegar ameliorates different diseases in which the inflammatory process orchestrated their development, including atopic dermatitis, arthritis, oxidative stress, and colitis [77, 78, 90, 104, 105]. In particular, fruit vinegar was found to control the production of the inflammatory markers, boost immune response, and control the gut microbiota that plays a pivotal role in the pathophysiology of asthma [102]. Dietary therapies are the first strategy to counteract different human diseases such as asthma [106, 107]. Squill oxymel as a traditional formulation containing vinegar as an ingredient, is used to treat severe persistent asthma, and its consumption for 6 weeks showed a significant improvement in forced expiratory volume in the first second (FEV1), forced expiratory flow between 25% and 75% (MEF 25–75%), also it was found that the formulation improved symptoms, activity, and score using pre- and post-intervention George’s respiratory questionnaire (SGRQ) [107]. The remarked beneficial properties of Oxymel could be due to its ability to modulate inflammatory processes and cholinergic activities [107]. In fact, the fruit vinegar administration successfully triggered inflammatory mediators in different animal models and human patients [20, 53, 55, 56, 107]. Scientific experiment showed that treatment with oak wood vinegar sustained 24 days attenuated the increase IgE production in 2,4-dinitrochlorobenzene (DNCB)-induced contact dermatitis mice model [78]. Additionally, nipa vinegar successfully proved its ability to suppress the expression of inflammatory mediators such as NF-kB and iNOS, which induce the reduction of NO levels (Fig. 1). The production of the highest amounts of NO indirectly activates Th2 cells, which are implicated in asthma physiopathology [108]. A historical review of inhalation therapies for asthma mentioned the vapor of vinegar [109]. Vinegar administration can adjust the production, secretion, and gene expression of airway mucin [110]. To establish confirmative evidence on the beneficial effects of fruit vinegar in asthma treatment, further investigative studies are needed. This could be a keystone of new original research.

Arthritis

Arthritis is a type of disease in which a chronic inflammatory process is involved and is characterized by discomfort and joint pain. Recently, the nutritional approach for illness conditions remains interesting because of its beneficial properties. Therefore, intensive scientific experiments have been conducted to confirm and examine the efficacy of this approach [111]. The investigation of the effect of apple cider vinegar in adjuvant arthritic rats is initiated by Ross et al., who concluded that this product is ineffective in treating this disease in rats [104]. In contrast, recent scientific evidence examined the ability of an innovative formulation of the Pangolin scale processed with vinegar (PSP) to decrease the arthritic index and inflammatory cell infiltration in the ankle joints of rats intoxicated by complete Freund’s adjuvant [112]. Accordingly, PSP lowered the serum levels of inflammatory cytokines, including TNF-α and IL-1ß [112]. Plentiful scientific evidence supports the ability of fruit vinegar to attenuate inflammatory processes induced by different toxic agents. However, other investigations are needed to elucidate the anti-arthritic effect of fruit vinegar.

Acute pancreatitis

The pancreas controls glycemia levels and is the target of numerous agents that induce acute pancreatitis, including drugs, alcohol, pancreatic ductal obstruction, and endoscopic retrograde cholangiopancreatography [113]. Calcium plays a pivotal role in acute pancreatitis installation through its elevation in acinar cells, which induces inflammation and pro-cell death [113]. In addition, mitochondrial dysfunction is implicated in the development of acute pancreatitis [114, 115]. Therefore, the control of mitochondrial function, calcium signaling pathways, and inflammatory processes could be useful in improving acute pancreatitis. Fruit vinegar has been widely used throughout the ages by several civilizations to treat digestive disorders [2]. The phytochemical complexity of fruit vinegar makes it a promising candidate for alleviating and treating many ailments, including inflammation, oxidative stress, obesity, and diabetes [3, 6, 15, 78, 116]. Pretreatment with vinegar demonstrated its ability to control voltage-dependent anion channel 1 (VDAC1), inhibit oxidative stress, and prevent mitochondrial dysfunction [117]. Tetramethylpyrazine is one of the most interesting active ingredients of vinegar, and it has been implicated in the prevention of acute pancreatitis in an animal model by inhibiting of nuclear factor-kappa B (NF-ĸß) [118]. Control of NF-ĸß activation and production of pro-inflammatory markers constitute a target of the therapeutic approach to acute pancreatitis. A study conducted by Choi et al. found that vinegar improved pro-inflammatory markers such as NO, iNOS, TNF-α IL-6, and MCP-1, which are involved in the inflammatory response [56]. Furthermore, ligustrazine, an active ingredient of vinegar, has shown promising results in acute pancreatitis, promoting acinar cell apoptosis at the early stage and downregulation the p38 and Erk MAP pathways [119]. There is no report on the beneficial effect of the direct administration of fruit vinegar on acute pancreatitis. Within this framework, further studies are needed to explore the pharmacological properties of vinegar on pancreatitis.

Colitis

Fruit vinegar is a natural product with multifaceted beneficial properties. It has been described as an effective cure for numerous human diseases recommended by several traditional healers [31]. Colitis is a type of disease treated with vinegar, and its effect was confirmed by Shizuma et al. by testing the ability of Kurozu (Traditional Japanese black vinegar) to attenuate dextran sulfate sodium-induced colitis. The authors showed that the administration of this product to C57 black 6 mice for twelve days proved a protective effect against the deleterious effects of DSS-induced colitis, decreasing nitrotyrosine levels and attenuating inflammatory modifications in rectal tissues [105]. In addition, Kurozu can suppress colitis symptoms such as bloody feces and body weight loss [120]. Vinegar has proven its potential to prevent the upregulation of IL-1ß and IL-6 mRNA (Fig. 2) [121]. Several studies indicate that fruit vinegar controls the development of different intestinal flora, thereby avoiding microbe-derived toxic metabolites, which could enhance the development of metabolic disorders. Fruit vinegar can maintain the homeostasis between luminal antigens and the intestinal defense system because of its potential to relieve the epithelial barrier and increase the number of commensal lactic or acetic acid-producing bacteria [55, 116].

Fig. 2.

Impact of bioactive compounds of fruit vinegar on different organs (Created in biorender.com)

The gastrointestinal tract is the main target of numerous agents causing ROS overproduction, which is attributed to toxic agents, dietary ingredients, pathogenic bacteria, and their interaction with immune cells [122, 123]. Treatment with vinegar or acetic acid was shown to be effective against histopathological damage induced by DSS-destroying crypts, mononuclear cell infiltration, goblet cell loss, and mucosal damage in the colon [116]. Vinegar ability to suppress Th1 and Th17 responses and attenuate inflammatory cytokine expression could explain its positive impact on colitis [116].

Limitations and future recommendations

The physical, chemical, and microbiological changes that occur during the fruit fermentation process have a significant impact on the vinegar’s quality and determine the final product’s distinctive aroma and flavor. Fruit vinegar could serve as a target for a variety of uses due to its physicochemical properties, including as an ecological solvent, a treatment for inflammatory diseases, and a cure for neurological disorders, and more. The major problem in investigating how fruit vinegar functions in humans is to conduct clinical investigations. Studies on ethnopharmacology have revealed a huge number of traditional uses for fruit vinegar that vary according to civilization, culture, religion, and region. However, it is crucial to identify the precise mechanisms underlying fruit vinegar’s anti-inflammatory and immunomodulatory effects.

Conclusion

As research progressed, fruit vinegar became an interesting food ingredient due to its wide spectrum of active compounds, ultimately affecting various target tissues. Emerging evidence from experimental studies on the anti-inflammatory effect of fruit vinegar for health-promoting features throughout controlling intestinal microbiota and pro-inflammatory cytokine production. Thus, the chemical complexity of vinegar constitutes a framework for intestinal flora to produce numerous compounds such as SCFAs implicated in different biological properties.

Supplementary information

Below is the link to the electronic supplementary material.

Author contributions

Conceptualization and writing original draft-review: Driss OUSAAID; writing, review, and editing: Meryem BAKOUR, Hassan LAAROUSSI, Asmae EL GHOUIZI; supervision: Badiaa LYOUSI and Ilham EL ARABI.

Funding

No funding received.

Data Availability

The data used to support the findings of this study are included within the article.

Declarations

Ethical approval

Not applicable.

Conflict of interest

The authors confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.