Gastrointestinal biotransformation of phytochemicals: Towards futuristic dietary therapeutics and functional foods

RG-I pectic polysaccharides and hesperidin synergistically modulate gut microbiota: An in vitro study targeting the proportional relationship

In this study, we investigated how different proportions blends of Rhamnogalacturonan-I pectic polysaccharides and hesperidin impact the gut microbiota and metabolites using an in vitro simulated digestion and fermentation model. The results indicated that both of them could modulate the gut microbiota and produce beneficial metabolites. However, their blends in particular proportions (such as 1:1) exhibited remarkable synergistic effects on modulating the intestinal microenvironment, surpassing the effects observed with individual components. Specifically, these blends could benefit the host by increasing short-chain fatty acids production (such as acetate), improving hesperidin bioavailability, producing more metabolites (such as hesperetin, phenolic acids), and promoting the growth of beneficial bacteria. This synergistic and additive effect was inseparable from the role of gut microbiota. Certain beneficial bacteria, such as Blautia, Faecalibacterium, and Prevotella, exhibited strong preferences for those blends, thereby contributing to host health through participating in carbohydrate and flavonoid metabolism.

Studies on in vivo antithrombotic activity of quercetin, a natural flavonoid isolated from a traditional medicinal plant, African eggplant (Solanum indicum)

ETHNOPHARMACOLOGICAL RELEVANCE

Every year, cardiovascular diseases (CVDs) account for about 17.9 million deaths, making them the primary cause of both morbidity and mortality. Conventional drugs, which are often prescribed to treat cardiovascular diseases, are costly and have adverse effects. Consequently, dietary modifications and other medications are needed. Traditional use of Solanum indicum as cardiotonic to treat hypertension and anticoagulant potency has been reported but poorly evaluated scientifically.

AIM OF THE STUDY

This study investigated the in vivo anticoagulant activity and mechanism of anticoagulation of quercetin (QC), a bioactive compound isolated from S. indicum (SI) hydroethanolic fruit extract.

MATERIALS AND METHODS

Bioassay-guided fractionation (anticoagulant activity) extracted QC from hydroethanolic SI extract. QC was extensively characterized biochemically and pharmacologically. The interaction between QC and thrombin was investigated using spectrofluorometric and isothermal calorimetric methods. Cytotoxicity, antiplatelet, and thrombolytic studies were carried out in vitro. The Swiss albino mice were used to assess the in vivo, anticoagulant, and antithrombotic activities of QC.

RESULTS

QC exhibits anticoagulant activity via (i) uncompetitive inhibition of thrombin but not FXa with a Ki value of 33.11 ± 4.2 μM and (ii) a partial inhibition of thrombin-catalyzed platelet aggregation with an IC50 value of 13.2 ± 1.2 μM. The experimental validation of the in silico study's prediction of QC's binding to thrombin was confirmed by spectrofluorometric and isothermal calorimetric analyses. QC was nontoxic to mammalian, non-hemolytic cells and demonstrated thrombolytic activity by activating plasminogen. QC demonstrated in vivo anticoagulant efficacy, preventing k-carrageen-induced thrombus formation in mice's tails. In the acute circulatory stasis paradigm in mice, QC reduces thromboxane B2 (TXB2) and endothelin-1 (ET-1) while increasing nitric oxide synthase (eNOS) and 6-keto prostaglandin F1α (6-keto-PGF1 α).

CONCLUSION

Effective in vivo anticoagulant and antithrombotic properties of S. indicum's bioactive component QC point to the plant's potential use as a herbal anticoagulant medication for preventing and treating cardiovascular diseases linked to thrombosis.

Deciphering Rickettsia conorii metabolic pathways: A treasure map to therapeutic targets

Indian tick typhus is an infectious disease caused by intracellular gram-negative bacteria Rickettsia conorii (R. conorii). The bacterium is transmitted to humans through bite of infected ticks and sometimes by lice, fleas or mites. The disease is restricted to some areas with few cases but in last decade it is re-emerging with large number of cases from different areas of India. The insight in to genetic makeup of bacterial pathogens can be derived from their metabolic pathways. In the current study 18 metabolic pathways were found to be unique to the pathogen (R. conorii). A comprehensive analysis revealed 163 proteins implicated in 18 unique metabolic pathways of R. conorii. 140 proteins were reported to be essential for the bacterial survival, 46 were found virulent and 10 were found involved in resistance which can enhance the bacterial pathogenesis. The functional analysis of unique metabolic pathway proteins showed the abundance of plasmid conjugal transfer TrbL/VirB6, aliphatic acid kinase short chain, signal transduction response regulator receiver and components of type IV transporter system domains. The proteins were classified into six broad categories on the basis of predicted domains, i.e., metabolism, transport, gene expression and regulation, antimicrobial resistance, cell signalling and proteolysis. Further, in silico analysis showed that 88 proteins were suitable therapeutic targets which do not showed homology with host proteins. The 43 proteins showed hits with the DrugBank database showing their druggable nature and remaining 45 proteins were classified as novel drug targets that require further validation. The study will help to provide the better understanding of pathogens survival and embark on the development of successful therapies for the management of Indian tick typhus.

In-vitro colonic fermentation of Kakadu plum (Terminalia ferdinandiana) fruit powder: Microbial biotransformation of phenolic compounds and cytotoxicity

Kakadu plum (Terminalia ferdinandiana) (KP) is an indigenous fruit used as a functional ingredient in powdered form. Three KP doses (1, 2.5 and 5 g) were digested in a dynamic in vitro gut digestion model over 48 h. Faecal water digests from the colonic reactors were assessed for total soluble polyphenols (TSP), ferric reducing antioxidant power (FRAP), phenolic metabolites and short-chain fatty acids (SCFAs). Effects of digests on cell viability were tested against Caco-2 intestinal and HepG2 hepatic cells. All doses of KP fermentation produced castalagin, corilagin, chebulagic acid, chebulinic acid, and gallic acid. TSP and FRAP significantly increased in 5 g KP digests at 0 and 48 h of fermentation. SCFA concentrations significantly increased after 48 h. Cytotoxic effects of 2.5 and 5 g KP digests diminished significantly after 12 h. Overall, colonic fermentation increased antioxidant activity and polyphenolic metabolites of 5 g KP powder for 48 h.

Potentially functional lactose-free ice cream with Lacticaseibacillus casei CSL3, ginger, and honey

AIMS

To develop and characterize a functional lactose-free ice cream with added ginger and honey, evaluate the survival of Lacticaseibacillus casei CSL3 under frozen storage and the simulated gastrointestinal tract (GIT), as well as antioxidant activity and product acceptability.

METHODS AND RESULTS

The survival of Lacticaseibacillus casei CSL3 was evaluated for 180 days, under frozen storage, and GIT at 60 days. At 15 days of storage, proximal composition, antioxidant activity, color, pH, acidity, fusion, density, overrun, and sensory analysis were performed. Ice cream was an effective food matrix for maintaining the viability of CSL3, with concentrations > 7 log CFU g- 1 during storage and GIT. In addition, the analysis showed overrun and prebiotic characteristics through high values of antioxidant activity and phenolic compounds, good acceptability, and purchase intention.

CONCLUSIONS

The product has satisfactory market potential (acceptance rate of 95.19% and purchase intention rate > 96%), and it could become another means of inserting probiotics in food.

Extraction of phenolic compounds from grape pomace using ohmic heating: Chemical composition, bioactivity and bioaccessibility

This study addresses the effectiveness of ohmic heating technology (OH) for the sustainable recovery of phenolic compounds from Grape Pomace (GP) by hydroethanolic extraction. GP extracts biological potential was evaluated in terms of antioxidant activity, cytotoxicity and preventive effect against reactive oxygen species (ROS). To understand if GP extracts can be used as a functional ingredient, simulated gastrointestinal digestion was performed to evaluate the bioaccessibility. OH-assisted hydroethanolic extraction proved to be an effective process for the recovery of GP phenolic compounds with high antioxidant capacity. The digestion process increased the concentration of total phenolics and the biotransformation of high-molecular phenolics (anthocyanins, flavonoids and resveratrol) in simpler phenolic acids, improving bioaccessibility. GP extract displayed a selective action against cancer cells (Caco-2 and HeLa) and promoted ROS prevention. The results highlighted the ability of OH to extract bioactives from GP and its potential application as a nutraceutical or for functional food formulations.

Polyphenolic Characterization and Anti-Inflammatory Effect of In Vitro Digested Extracts of Echinacea purpurea L. Plant Parts in an Inflammatory Model of Human Colon Cells

Echinacea purpurea L. (EP) preparations are globally popular herbal supplements known for their medicinal benefits, including anti-inflammatory activities, partly related to their phenolic composition. However, regarding their use for the management of inflammation-related intestinal diseases, the knowledge about the fate of orally ingested constituents throughout the human gastrointestinal tract and the exposition of in vitro digested extracts in relevant inflammatory models are unknown. This study investigated for the first time the impact of in vitro gastrointestinal digestion (INFOGEST) on the phenolic composition and anti-inflammatory properties of EP extracts from flowers (EF), leaves (EL), and roots (ER) on IL-1β-treated human colon-derived CCD-18Co cells. Among the seven hydroxycinnamic acids identified using HPLC-UV-MS/MS, chicoric and caftaric acids showed the highest concentrations in EL, followed by EF and ER, and all extracts exerted significant reductions in IL-6, IL-8, and PGE2 levels. After digestion, despite reducing the bioaccessibility of their phenolics, the anti-inflammatory effects were preserved for digested EL and, to a lesser extent, for EF, but not for digested ER. The lower phenolic content in digested EF and ER could explain these findings. Overall, this study emphasizes the potential of EP in alleviating intestinal inflammatory conditions and related disorders.

Complexation of starch and phenolic compounds during food processing and impacts on the release of phenolic compounds

Phenolic compounds can form complexes with starch during food processing, which can modulate the release of phenolic compounds in the gastrointestinal tract and regulate the bioaccessibility of phenolic compounds. The starch-phenolic complexation is determined by the structure of starch, phenolic compounds, and the food processing conditions. In this review, the complexation between starch and phenolic compounds during (hydro)thermal and nonthermal processing is reviewed. A hypothesis on the complexation kinetics is developed to elucidate the mechanism of complexation between starch and phenolic compounds considering the reaction time and the processing conditions. The subsequent effects of complexation on the physicochemical properties of starch, including gelatinization, retrogradation, and digestion, are critically articulated. Further, the release of phenolic substances and the bioaccessibility of different types of starch-phenolics complexes are discussed. The review emphasizes that the processing-induced structural changes of starch are the major determinant modulating the extent and manner of complexation with phenolic compounds. The controlled release of complexes formed between phenolic compounds and starch in the digestive tracts can modify the functionality of starch-based foods and, thus, can be used for both the modulation of glycemic response and the targeted delivery of phenolic compounds.

New Insights of Biological Functions of Natural Polyphenols in Inflammatory Intestinal Diseases

The intestine is critically crucial for nutrient absorption and host defense against exogenous stimuli. Inflammation-related intestinal diseases, including enteritis, inflammatory bowel disease (IBD), and colorectal cancer (CRC), are heavy burdens for human beings due to their high incidence and devastating clinical symptoms. Current studies have confirmed that inflammatory responses, along with oxidative stress and dysbiosis as critical pathogenesis, are involved in most intestinal diseases. Polyphenols are secondary metabolites derived from plants, which possess convincible anti-oxidative and anti-inflammatory properties, as well as regulation of intestinal microbiome, indicating the potential applications in enterocolitis and CRC. Actually, accumulating studies based on the biological functions of polyphenols have been performed to investigate the functional roles and underlying mechanisms over the last few decades. Based on the mounting evidence of literature, the objective of this review is to outline the current research progress regarding the category, biological functions, and metabolism of polyphenols within the intestine, as well as applications for the prevention and treatment of intestinal diseases, which might provide ever-expanding new insights for the utilization of natural polyphenols.

Impact of nanotechnology on the oral delivery of phyto-bioactive compounds

Nanotechnology is an advanced field that has remarkable nutraceutical and food applications. Phyto-bioactive compounds (PBCs) play critical roles in promoting health and disease treatment. However, PBCs generally encounter several limitations that delay their widespread application. For example, most PBCs have low aqueous solubility, poor biostability, poor bioavailability, and a lack of target specificity. Moreover, the high concentrations of effective PBC doses also limit their application. As a result, encapsulating PBCs into an appropriate nanocarrier may increase their solubility and biostability and protect them from premature degradation. Moreover, nanoencapsulation could improve absorption and prolong circulation with a high opportunity for targeted delivery that may decrease unwanted toxicity. This review addresses the main parameters, variables, and barriers that control and affect oral PBC delivery. Moreover, this review discusses the potential role of biocompatible and biodegradable nanocarriers in improving the water solubility, chemical stability, bioavailability, and specificity/selectivity of PBCs.

Epigenetic regulation by metabolites from the gut microbiome

The gut microbiome can metabolise food components, such as dietary fibres and various phytochemicals; and the microbiome can also synthesise some nutrients, for example B vitamins. The metabolites produced by bacteria and other micro-organisms in the colon can have implications for health and disease risk. Some of these metabolites are epigenetically active, and can contribute to changes in the chemical modification and structure of chromatin by affecting the activity and expression of epigenetically-active enzymes, for example histone deacetylases and DNA methyltransferases. The epigenetic activity of such gut microbiome metabolites is reviewed herein.

A Novel Streptococcus thermophilus FUA329 Isolated from Human Breast Milk Capable of Producing Urolithin A from Ellagic Acid

Urolithin A, a metabolite of ellagic acid, has many beneficial biological activities for people. Strains capable of producing urolithin A from ellagic acid have the hope of becoming the next-generation probiotics. However, only a few species of these strains have been reported. In this study, FUA329, a strain capable of converting ellagic acid to urolithin A in vitro, was isolated from the breast milk of healthy Chinese women. The results of morphological observation, physiological and biochemical tests, and 16S rRNA gene sequence analysis confirmed that the strain FUA329 was Streptococcus thermophilus. In addition, the S. thermophilus FUA329 growth phase is consistent with the degradation of ellagic acid, and urolithin A was produced in the stationary phase, with a maximum concentration of 7.38 μM at 50 h. The corresponding conversion efficiency of urolithin A from ellagic acid was 82%. In summary, S. thermophilus FUA329, a novel urolithin A-producing bacterium, would be useful for the industrial production of urolithin A and may be developed as a next-generation probiotic.

Rethinking healthy eating in light of the gut microbiome

Given the worldwide epidemic of diet-related chronic diseases, evidence-based dietary recommendations are fundamentally important for health promotion. Despite the importance of the human gut microbiota for the physiological effects of diet and chronic disease etiology, national dietary guidelines around the world are just beginning to capitalize on scientific breakthroughs in the microbiome field. In this review, we discuss contemporary nutritional recommendations from a microbiome science perspective, focusing on mechanistic evidence that established host-microbe interactions as mediators of the physiological effects of diet. We apply this knowledge to inform discussions of nutrition controversies, advance innovative dietary strategies, and propose an experimental framework that integrates the microbiome into nutrition research. The congruence of key paradigms in the nutrition and microbiome disciplines validates current recommendations in dietary guidelines, and the systematic incorporation of microbiome science into nutrition research has the potential to further improve and innovate healthy eating.

Antioxidant Activity and Mechanism of Resveratrol and Polydatin Isolated from Mulberry (Morus alba L.)

Natural stilbenes have unique physiological effects, such as anti-senile dementia, anti-cancer, anti-bacterial, lowering blood lipid, and other important biological functions, which have attracted great attention from scholars in recent years. In this study, two stilbene compounds, resveratrol (RES) and polydatin (PD), were isolated from Mulberry (Morus alba L.), and their antioxidant activity and mechanism were investigated. The results showed that the contents of RES and PD in mulberry roots were 32.45 and 3.15 μg/g, respectively, significantly higher than those in mulberry fruits (0.48 and 0.0020 μg/g) and mulberry branches (5.70 and 0.33 μg/g). Both RES and PD showed high antioxidant potential by DPPH, ABTS free-scavenging methods, and ORAC assay, and provided protection against oxidative damage in HepG2 cells by increased catalase (CAT) activity, superoxide dismutase (SOD) activity, and Glutathione (GSH) content, and decreasing generation of reactive oxygen species (ROS), lactate dehydrogenase (LDH) level, and malondialdehyde (MDA) content. Therefore, RES and PD treatment could be effective for attenuating AAPH-induced oxidative stress in HepG2 cells. This study will promote the development and application of stilbene compounds. Furthermore, the RES and PD could be used as antioxidant supplements in functional foods, cosmetics, or pharmaceuticals, contributing to health improvement.

Shaping the gut microbiota by bioactive phytochemicals: An emerging approach for the prevention and treatment of human diseases

The human digestive tract is the cottage to trillions of live microorganisms, which regulate health and illness. A healthy Gut Microbiota (GM) is necessary for preventing microbial growth, body growth, obesity, cancer, diabetes, and enhancing immunity. The equilibrium in GM's composition and the presence/absence of critical species enable specific responses to be essential for the host's better health condition. Research evidences revealed that the dietary plants and their bioactive phytochemicals (BPs) play an extensive and critical role in shaping the GM to get beneficial health effects. BPs are also known to improve gastrointestinal health and reduce the risk of several diseases by modulating GM-mediated cellular and molecular processes. Regular intake of BPs-rich vegetables, fruits, and herbal preparations promotes probiotic bacteria, including Bifidobacteria and Lactobacillus species, while inhibiting unwanted gut residents' development Escherichia coli, and Salmonella typhimurium etc. Upon consumption, BPs contact the GM that gets transformed before being absorbed from the gastrointestinal tract. Biotransformation of BPs by GM is linked with the enhancement of bioactivity/toxicity diminishment of the BPs compared to parental phytochemicals. Therefore, the current review focuses on the role of BPs in shaping GM for the prevention and treatment of human diseases.

Understanding the Gastrointestinal Protective Effects of Polyphenols using Foodomics-Based Approaches

Plant polyphenols are rich sources of natural anti-oxidants and prebiotics. After ingestion, most polyphenols are absorbed in the intestine and interact with the gut microbiota and modulated metabolites produced by bacterial fermentation, such as short-chain fatty acids (SCFAs). Dietary polyphenols immunomodulatory role by regulating intestinal microorganisms, inhibiting the etiology and pathogenesis of various diseases including colon cancer, colorectal cancer, inflammatory bowel disease (IBD) and colitis. Foodomics is a novel high-throughput analysis approach widely applied in food and nutrition studies, incorporating genomics, transcriptomics, proteomics, metabolomics, and integrating multi-omics technologies. In this review, we present an overview of foodomics technologies for identifying active polyphenol components from natural foods, as well as a summary of the gastrointestinal protective effects of polyphenols based on foodomics approaches. Furthermore, we critically assess the limitations in applying foodomics technologies to investigate the protective effect of polyphenols on the gastrointestinal (GI) system. Finally, we outline future directions of foodomics techniques to investigate GI protective effects of polyphenols. Foodomics based on the combination of several analytical platforms and data processing for genomics, transcriptomics, proteomics and metabolomics studies, provides abundant data and a more comprehensive understanding of the interactions between polyphenols and the GI tract at the molecular level. This contribution provides a basis for further exploring the protective mechanisms of polyphenols on the GI system.