Effect of polyphenols isolated from purple sweet potato (Ipomoea batatas cv. Ayamurasaki) on the microbiota and the biomarker of colonic fermentation in rats fed with cellulose or inulin

The mutual effect of dietary fiber and polyphenol on gut microbiota: Implications for the metabolic and microbial modulation and associated health benefits

Gut microbiota plays a critical role in maintaining human health by regulating digestion, metabolism, and immune function. Emerging research highlights the potential of dietary interventions, particularly dietary fiber (DF) and polyphenols, in modulating gut microbiota composition and function. DF serves as a fermentable substrate for beneficial gut bacteria, promoting the production of short-chain fatty acids (SCFAs). Polyphenols, a diverse group of bioactive compounds selectively modulate microbial populations and contribute to the production of bioactive metabolites with host health benefits. Importantly, the interplay between DF and polyphenols creates a synergistic effect within the gut microbiome, shaping microbial diversity, enhancing SCFAs production, and strengthening gut barrier function, which together support metabolic and immune homeostasis. This review systematically explores the synergistic effects of DF-polyphenol combinations on gut microbiota modulation, microbial metabolites, and their implications for overall health. The combined effects of DF and polyphenols hold promise for targeted nutritional strategies in preventing metabolic disorders and improving gut health. Moreover, the extent of these benefits is influenced by the structural characteristics of DF, the source and dosage of polyphenols, and individual gut microbiota composition. Further research is warranted to optimize DF-polyphenol interactions and facilitate their applications in personalized nutrition and functional food development.

Polyphenols and Microbiota Modulation: Insights from Swine and Other Animal Models for Human Therapeutic Strategies

High consumption of ultra-processed foods, rich in sugar and unhealthy fats, has been linked to the onset of numerous chronic diseases. Consequently, there has been a growing shift towards a fiber-rich diet, abundant in fruits, vegetables, seeds, and nuts, to enhance longevity and quality of life. The primary bioactive components in these plant-based foods are polyphenols, which exert significant effects on modulating the gastrointestinal microbiota through their antioxidant and anti-inflammatory activities. This modulation has preventive effects on neurodegenerative, metabolic, and cardiovascular diseases, and even cancer. The antimicrobial properties of polyphenols against pathogenic bacteria have significantly reduced the need for antibiotics, thereby lowering the risk of antibiotic resistance. This paper advances the field by offering novel insights into the beneficial effects of polyphenols, both directly through the metabolites produced during digestion and indirectly through changes in the host's gastrointestinal microbiota, uniquely emphasizing swine as a model highly relevant to human health, a topic that, to our knowledge, has not been thoroughly explored in previous reviews. This review also addresses aspects related to both other animal models (mice, rabbits, and rats), and humans, providing guidelines for future research into the benefits of polyphenol consumption. By linking agricultural and biomedical perspectives, it proposes strategies for utilizing these bioactive compounds as therapeutic agents in both veterinary and human health sciences.

Effects of Lactic Acid Bacteria Fermentation and In Vitro Simulated Digestion on the Bioactivities of Purple Sweet Potato Juice

The effects of lactic acid bacteria fermentation and in vitro simulated digestion on phenolic bioavailability, phenolic bioavailability, and antioxidant activity of purple sweet potato juice (PSPJ) were investigated. The PSPJ was fermented by Lactobacillus rhamnosus and Streptococcus thermophilus. The viable bacterial count, phenolic components, antioxidant activity, phenolic bioaccessibility, and phenolic bioavailability of PSPJ were analyzed during the simulated digestion process in vitro. The data displayed that lactic acid bacteria fermentation increased total α-glucosidase inhibition, total flavonoid content, and ratephenolic content. The antioxidant activities were improved after in vitro simulated digestion due to the biotransformation of phenolic substances by lactic acid bacteria fermentation. The bioaccessibility and bioavailability of phenols in PSPJ were improved with fermentation of lactic acid bacteria. Furthermore, the viable bacteria count of the two strains was significantly improved (>7 log CFU/mL) after simulated digestion in vitro.

Dose-Dependent Effects of Turmeric (Curcuma aromatica S.) Starch on Colonic Fermentation in Rats

Background; Turmeric starch (TS) has gained significant attention due to its potential health benefits. Rich in resistant starch (RS) and higher in phosphorus, TS is anticipated to possess properties of high-phosphorus-type RS. Objectives; To understand the host physiology of TS, this study investigated the dose-dependent effects of TS on colonic fermentation in rats. Methods; Four experimental diets containing different levels of TS (5%, 10%, and 20% w/w) were formulated and fed to male Fischer 344 rats for two weeks and compared with rats fed a 0% TS diet (TS0). Results; Results showed that increasing the dose of TS resulted in reduced body weight gain, lower visceral tissue weight, and increased cecal mucin and IgA levels compared with the TS0 group. Further, fecal dry weight increased dose-dependently parallel to the starch excretion rate. Higher doses of TS resulted in increased short chain fatty acid (SCFA) production, specifically cecal acetate content, as well as in a dose-dependent decrease in the cecal pH level. However, this study did not observe a positive effect of TS on colonic alkaline phosphatase (ALP) activity, and the impact on small intestinal ALP activity remains unclear. Notably, beneficial bacteria such as the family Oscillospiraceae, genus Lachnospiraceae NK4A136 group, and Ruminococcus spp. were found to have been enriched in the TS-fed groups, further supporting the beneficial effects of TS on gut microbiota and SCFA production. Additionally, the genus Mucispirillum, which is known to possess beneficial and opportunistic pathogenic traits under immunocompromised states, was found in the TS-fed groups. Conclusions; According to these results, it is clear that TS served as a prebiotic substrate in rats, with a notable modulation of the microbial composition.

Proximate Composition, Health Benefits, and Food Applications in Bakery Products of Purple-Fleshed Sweet Potato (Ipomoea batatas L.) and Its By-Products: A Comprehensive Review

Ipomoea batatas (L.) Lam is a dicotyledonous plant originally from tropical regions, with China and Spain acting as the main producers from outside and within the EU, respectively. The root, including only flesh, is the edible part, and the peel, leaves, stems, or shoots are considered by-products, which are generated due to being discarded in the field and during processing. Therefore, this study aimed to perform a comprehensive review of the nutritional value, phytochemical composition, and health-promoting activities of purple-fleshed sweet potato and its by-products, which lead to its potential applications in bakery products for the development of functional foods. The methodology is applied to the selected topic and is used to conduct the search, review abstracts and full texts, and discuss the results using different general databases. The studies suggested that purple-fleshed sweet potato parts are characterized by a high content of essential minerals and bioactive compounds, including anthocyanins belonging to the cyanidin or the peonidin type. The flesh and leaves are also high in phenolic compounds and carotenoids such as lutein and β-carotene. The high content of phenolic compounds and anthocyanins provides the purple-fleshed sweet potato with high antioxidant and anti-inflammatory power due to the modulation effect of the transcription factor Nrf2 and NF-kB translocation, which may lead to protection against hepatic and neurological disorders, among others. Furthermore, purple-fleshed sweet potato and its by-products can play a dual role in food applications due to its attractive color and wide range of biological activities which enhance its nutritional profile. As a result, it is essential to harness the potential of the purple-fleshed sweet potato and its by-products that are generated during its processing through an appropriate agro-industrial valorization system.

Microbial tryptophan catabolism as an actionable target via diet-microbiome interactions

In recent years, the role of microbial tryptophan (Trp) catabolism in host-microbiota crosstalk has become a major area of scientific interest. Microbiota-derived Trp catabolites positively contribute to intestinal and systemic homeostasis by acting as ligands of aryl hydrocarbon receptor and pregnane X receptor, and as signaling molecules in microbial communities. Accumulating evidence suggests that microbial Trp catabolism could be therapeutic targets in treating human diseases. A number of bacteria and metabolic pathways have been identified to be responsible for the conversion of Trp in the intestine. Interestingly, many Trp-degrading bacteria can benefit from the supplementation of specific dietary fibers and polyphenols, which in turn increase the microbial production of beneficial Trp catabolites. Thus, this review aims to highlight the emerging role of diets and food components, i.e., food matrix, fiber, and polyphenol, in modulating the microbial catabolism of Trp and discuss the opportunities for potential therapeutic interventions via specifically designed diets targeting the Trp-microbiome axis.

Non-Digestible Carbohydrates: Green Extraction from Food By-Products and Assessment of Their Effect on Microbiota Modulation

The nature and composition of the waste produced by food industrial processing make its abundance and accumulation an environmental problem. Since these by-products may present a high potential for revalorization and may be used to obtain added-value compounds, the main goals of the technological advancements have been targeted at reducing the environmental impact and benefiting from the retrieval of active compounds with technological and health properties. Among the added-value substances, nondigestible carbohydrates have demonstrated promise. In addition to their well-known technological properties, they have been discovered to modify the gut microbiota and enhance immune function, including the stimulation of immune cells and the control of inflammatory reactions. Furthermore, the combination of these compounds with other substances such us phenols could improve their biological effect on different noncommunicable diseases through microbiota modulation. In order to gain insight into the implementation of this combined strategy, a broader focus concerning different aspects is needed. This review is focused on the optimized green and advanced extraction system applied to obtain added-value nondigestible carbohydrates, the combined administration with phenols and their beneficial effects on microbiota modulation intended for health and/or illness prevention, with particular emphasis on noncommunicable diseases. The isolation of nondigestible carbohydrates from by-products as well as in combination with other bioactive substances could provide an affordable and sustainable source of immunomodulatory chemicals.

Resistant starch from sweet potatoes: Recent advancements and applications in the food sector

In tropical and subtropical areas, tuber and root crops are staple foods and a key source of energy. Sweet potato (SP) is currently regarded as one of the world's top ten foods because of its diverse sizes, shapes, color, and health benefits. The resistant starch (RS) content of SP is substantial. It is predicted to become the cheapest item in the food industry due to its extensive variety, food stability, emulsifier and fat substitution capabilities, and as filler. As a result, interest in SP-sourced RS has recently increased. Due to their unique nutritional and functional qualities, novelty has become a popular research focus in recent years. This review will summarize the current understanding of SP starch components and their impact on the technological and physicochemical properties of produced starch for commercial viability. The importance of sweet potato RS in addressing future RS demand sustainability is emphasized. SPs are a viable alternative to tubers as a sustainable raw material for RS production. It has an advantage over tubers because of its intrinsic nutritional value and climatic endurance. Thermal, chemical, and enzymatic treatments are effective RS manufacturing procedures. The adaptability of sweet potato RS allows for a wide range of food applications.

Promoting intestinal IgA production in mice by oral administration with anthocyanins

While recent years have witnessed ever-growing evidence on the prebiotic attributes of anthocyanins for treatment of microbiota-associated diseases, the complex interplay between anthocyanin uptake, the gut microbiota, and the intestinal mucosal immune system remains poorly understood. Here, we investigate the effects of bilberry anthocyanins on the gut microbiota composition and metabolism, and the intestinal mucosal immune system of mice. We observed an increased proportion of IgA-producing plasma cells in the mesenteric lymph nodes (MLNs) and an enhanced secretion of secretory immunoglobulin A (sIgA) and antimicrobial peptides in the small intestine. Small intestine transcriptome analysis further suggested that anthocyanins influenced IgA production. We found that oral administration of anthocyanins altered the gut microbiota through maintaining the anaerobic intestinal environment, promoting the secretion of sIgA and antimicrobial peptides, and downregulating cell motility and mobile genetic elements of commensal bacteria. These observations suggest that the oral administration of anthocyanins helps in maintaining intestinal homeostasis and thus it may find applications in immunotherapy and related fields.

A blend of 3 mushrooms dose-dependently increases butyrate production by the gut microbiota

The gut microbiota has been indicated to play a crucial role in health and disease. Apart from changes in composition between healthy individuals and those with a disease or disorder, it has become clear that also microbial activity is important for health. For instance, butyrate has been proven to be beneficial for health, because, amongst others, it is a substrate for the colonocytes, and modulates the host's immune system and metabolism. Here, we studied the effect of a blend of three mushrooms (Ganoderma lucidum GL AM P-38, Grifola frondosa GF AM P36 and Pleurotus ostreatus PO AM-GP37)) on gut microbiota composition and activity in a validated, dynamic, computer-controlled in vitro model of the colon (TIM-2). Predigested mushroom blend at three doses (0.5, 1.0 and 1.5 g/day of ingested mushroom blend) was fed to a pooled microbiota of healthy adults for 72 h, and samples were taken every day for microbiota composition (sequencing of amplicons of the V3-V4 region of the 16S rRNA gene) and activity (short-chain fatty acid (SCFA) production). The butyrate producing genera Lachnospiraceae UCG-004, Lachnoclostridium, Ruminococcaceae UCG-002 and Ruminococcaceae NK4A214-group are all dose-dependently increased when the mushroom blend was fed. Entirely in line with the increase of these butyrate-producers, the cumulative amount of butyrate also dose-dependently increased, to roughly twice the amount compared to the control (medium without mushroom blend) on the high-dose mushroom blend. Butyrate proportionally made up 53.1% of the total SCFA upon feeding the high-dose mushroom blend, compared to 27% on the control medium. In conclusion, the (polysaccharides in the) mushroom blend led to substantial increase in butyrate by the gut microbiota. These results warrant future mechanistic research on the mushroom blend, as butyrate is considered to be one of the microbial metabolites that contributes to health, by increasing barrier function and modulating inflammation.

Dietary Ethanolamine Plasmalogen Alleviates DSS-Induced Colitis by Enhancing Colon Mucosa Integrity, Antioxidative Stress, and Anti-inflammatory Responses via Increased Ethanolamine Plasmalogen Molecular Species: Protective Role of Vinyl Ether Linkages

Dietary ethanolamine plasmalogen (PlsEtn) has been reported to have several health benefits; however, its functional role during colon pathophysiology remains elusive. The present study investigated the anticolitis effect of dietary ethanolamine glycerophospholipids (EtnGpls) with high PlsEtn from ascidian muscle (86.2 mol %) and low PlsEtn from porcine liver (7.7 mol %) in dextran sulfate sodium (DSS)-induced colitis in mice. Dietary EtnGpls lowered myeloperoxidase activity, thiobarbituric acid-reactive substances, proinflammatory cytokines and proapoptosis-related protein levels in colon mucosa after 16 days of DSS treatment, with ascidian muscle (0.1% EtnGpl in diet) showing higher suppression than porcine liver (0.1% EtnGpl in diet). Moreover, dietary EtnGpls suppressed DSS symptoms after 38 days of DSS treatment as evidenced by increased body weight, colon length, and ameliorated colon mucosa integrity. Additionally, dietary EtnGpls elevated short-chain fatty acid production in DSS-treated mice. Altogether, these results indicate the potential of utilizing diets with abundant PlsEtn for the prevention of colon inflammation-related disorders.

Immune-Enhancing Effects of a Novel Glucan from Purple Sweet Potato Ipomoea batatas (L.) Lam on RAW264.7 Macrophage Cells via TLR2- and TLR4-Mediated Pathways

PSPP-1 was obtained from purple sweet potato, and the effects of PSPP-1 on the immune modulation on macrophage cells were investigated for the first time. PSPP-1 promoted RAW264.7 proliferation and increased the total cell percentage in DNA synthesis and mitosis phases, and the cell morphology changed in volume and appearance. Additionally, the RAW264.7 immune functions of phagocytic activity and nitric oxide, reactive oxygen species, and cytokine production were improved by PSPP-1. The western blot experiment showed that PSPP-1 could activate toll-like receptor 2 and toll-like receptor 4-mediated pathways, and the expressions of proteins in MyD88-dependent, mitogen-activated protein kinase (MAPK)-signaling, NF-κB-signaling, AP-1 signaling, and TRIF-dependent pathways were improved markedly. Molecular docking and Biolayer Interferometry study further indicated that PSPP-1 could recognize and bind TLR2 and TLR4 by targeting the binding sites with a strong affinity. It suggested that PSPP-1 could enhance immunity via TLR2- and TLR4-mediated pathways, and it could be explored as an immunomodulatory agent.