A specific gut microbiota and metabolomic profiles shifts related to antidiabetic action: The similar and complementary antidiabetic properties of type 3 resistant starch from Canna edulis and metformin

The mechanisms in the gut microbiota regulation and type 2 diabetes therapeutic activity of resistant starches

Resistant starch (RS) can potentially prevent type 2 diabetes through the modulation of intestinal microbiota and microbial metabolites. Currently, it has been wildly noted that altering the intestinal microbial composition and short-chain fatty acids levels can achieve therapeutic effects, although the specific mechanisms were rarely elucidated. This review systematically explores the structural characteristics of different RS, analyzes the cross-feeding mechanism utilized by intestinal microbiota, and outlines the pathways and targets of butyrate, a primary microbial metabolite, for treating diabetes. Different RS types may have a unique impact on microbiota composition and their cross-feeding, thus exploring regulatory mechanisms of RS on diabetes through intestinal flora interaction and their metabolites could pave the way for more effective treatment outcomes for host health. Furthermore, by understanding the mechanisms of strain-level cross-feeding and metabolites of RS, precise dietary supplementation methods targeted at intestinal composition and metabolites can be achieved to improve T2DM.

Effects of debranched starch on physicochemical properties and in vitro digestibility of flat rice noodles

Aiming to develop flat rice noodles with both desirable textural quality and lower starch digestibility, we investigated the effect of adding indica rice debranched starch (RDBS) on the quality of flat rice noodles. In this study, adding RDBS to flat rice noodles enhanced their mechanical properties. Cooking characteristic analysis showed that incorporating RDBS into dried flat rice noodles increased the rehydration ratio by 16.1 % and reduced rehydration time by 26.5 %. Scanning electron microscopy (SEM) revealed the presence of microparticles formed through the self-assembly of RDBS within the network of flat rice noodles. X-ray diffraction (XRD) analysis demonstrated that the addition of RDBS elevated the crystallinity of the flat rice noodles, rising from 9.59 % to 22.57 %. In addition, the in vitro simulated digestion test suggested the addition of RDBS led to a threefold increase in the content of slowly digestible starch (SDS) and a ninefold increase in resistant starch (RS) content in flat rice noodles. This study found that adding RDBS into flat rice noodles can effectively reduce their digestion rate and improve their eating quality. It could be a promising approach for creating functional rice noodles aimed at alleviating public health concerns such as diabetes and obesity.

Type 3 resistant starch from Canna edulis reduce lipid levels in patients with mild hyperlipidemia through altering gut microbiome: A double- blind randomized controlled trial

Type 3 resistant starch from Canna edulis (Ce-RS3) is an insoluble dietary fiber which could improve blood lipids in animals, but clinically robust evidence is still lacking. We performed a double-blind randomized controlled trial to assess the effects of Ce-RS3 on lipids in mild hyperlipidemia. One hundred and fifteen patients were included followed the recruitment criteria, and were randomly allocated to receive Ce-RS3 or placebo (native starch from Canna edulis) for 12 weeks (20 g/day). In addition to serum lipids, complete blood counts, serum inflammatory factors, antioxidant indexes, and dietary survey, 16 S rRNA sequencing technique was utilized to analyze the gut microbiota alterations. Targeted quantitative metabolomics (TQM) was used to detect metabolite changes. Compared with the placebo, Ce- RS3 significantly decreased levels of total cholesterol, lowdensity lipoprotein cholesterol, and non-high-density lipoprotein cholesterol, and increased the glutathione peroxidase. Based on the 16 S rRNA sequencing, TQM, the correlation analysis, as well as the Kyoto Encyclopedia of Genes (KEGG) and Genomes and Human Metabolome Database (HMDB) analysis, we found that Ce-RS3 could increase the abundances of genera Faecalibacterium and Agathobacter, while reduce the abundances of genera norank_f_Ruminococcaceae and Christensenellaceae_R-7_ group to regulate phenylalanine metabolism, which could reduce the fatty acid biosynthesis and fatty acid elongation in the mitochondria to lower blood lipids. Conclusively, we firstly confirmed the feasibility of Ce-RS3 for clinical application, which presents a novel, effective therapy for the mild hyperlipidemia. (Chictr. org. cn. Clinical study on anti-mild hyperlipidemia of Canna edulis RS3 resistant starch, ID Number: ChiCTR2200062871).

Structural analysis of type 3 resistant starch from Canna edulis during in vitro simulated digestion and its post-digested residue impact on human gut microbiota

Introduction

Resistant starch (RS) has garnered attention for its health benefits, including modulating the gut microbiota and promoting the production of short-chain fatty acids (SCFAs).

Methods

This study investigates structural changes of type 3 resistant starch from Canna edulis (CE) during in vitro simulated digestion and explores its health-relevant properties using healthy individuals' fecal microbiota.

Results

CE, prepared with a RS content of 59.38%, underwent a comprehensive analysis employing X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). During simulated digestion, XRD analysis demonstrated a significant rise in CE's relative crystallinity from 38.92 to 49.34%. SEM illustrated the transition of CE from a smooth to a rough surface, a notable morphological shift. Post-digestion, CE was introduced into microbial fermentation. Notably, propionic acid and valeric acid levels significantly increased compared to the control group. Furthere more, beneficial Bifidobacterium proliferated while pathogenic Escherichia-Shigella was suppressed. When comparing CE to the well-known functional food fructo-oligosaccharide (FOS), CE showed a specific ability to support the growth of Bifidobacterium and stimulate the production of short-chain fatty acids (SCFAs) without causing lactic acid accumulation.

Discussion

CE demonstrates potential as a functional health food, with implications for gut health enhancement and SCFAs production.

The effects of Atractylodes macrocephala extract BZEP self-microemulsion based on gut-liver axis HDL/LPS signaling pathway to ameliorate metabolic dysfunction-associated fatty liver disease in rats

OBJECTIVES

To elucidate the therapeutic effects and mechanisms of Atractylodes macrocephala extract crystallize (BZEP) and BZEP self-microemulsion (BZEPWR) on metabolic dysfunction-associated fatty liver disease (MAFLD) induced by "high sugar, high fat, and excessive alcohol consumption" based on the gut-liver axis HDL/LPS signaling pathway.

METHODS

In this study, BZEP and BZEPWR were obtained via isolation, purification, and microemulsification. Furthermore, an anthropomorphic MAFLD rat model of "high sugar, high fat, and excessive alcohol consumption" was established. The therapeutic effects of BZEPWR and BZEP on the model rats were evaluated in terms of liver function, lipid metabolism (especially HDL-C), serum antioxidant indexes, and liver and intestinal pathophysiology. To determine the lipoproteins in the serum sample, the amplitudes of a plurality of NMR spectra were derived via deconvolution of the composite methyl signal envelope to yield HDL-C subclass concentrations. The changes in intestinal flora were detected via 16 S rRNA gene sequencing. In addition, the gut-liver axis HDL/LPS signaling pathway was validated using immunohistochemistry, immunofluorescence, and western blot.

RESULTS

The findings established that BZEPWR and BZEP improved animal signs, serum levels of liver enzymes (ALT and AST), lipid metabolism (TC, TG, HDL-C, and LDL-C), and antioxidant indexes (GSH, SOD, and ROS). In addition, pathological damage to the liver, colon, and ileum was ameliorated, and the intestinal barrier function of the model rats was restored. At the genus level, BZEPWR and BZEP exerted positive effects on beneficial bacteria, such as Lactobacillus and norank_f__Muribaculaceae, and inhibitory effects on harmful bacteria, such as unclassified_f__Lachnospiraceae and Blautia. Twenty HDL-C subspecies were detected, and their levels were differentially increased in both BZEPWR and BZEP groups, with BZEPWR exhibiting a stronger elevating effect on specific HDL-C subspecies. Also, the gut-liver axis HDL/LPS signaling pathway was studied, which indicated that BZEPWR and BZEP significantly increased the expressions of ABCA1, LXR, occludin, and claudin-1 proteins in the gut and serum levels of HDL-C. Concomitantly, the levels of LPS in the serum and TLR4, Myd88, and NF-κB proteins in the liver were decreased.

CONCLUSION

BZEPWR and BZEP exert restorative and reversal effects on the pathophysiological damage to the gut-liver axis in MAFLD rats, and the therapeutic mechanism may be related to the regulation of the intestinal flora and the HDL/LPS signaling pathway.

Association of the short-chain fatty acid levels and dietary quality with type 2 diabetes: a case-control study based on Henan Rural Cohort

Evidence of the relationship between fecal short-chain fatty acids (SCFA) levels, dietary quality and type 2 diabetes mellitus (T2DM) in rural populations is limited. Here, we aimed to investigate the association between fecal SCFA levels and T2DM and the combined effects of dietar quality on T2DM in rural China. In total, 100 adults were included in the case-control study. Dietary quality was assessed by the Alternate Healthy Eating Index 2010 (AHEI-2010), and SCFA levels were analysed using the GC-MS system. Generalised linear regression was conducted to calculate the OR and 95 % CI to evaluate the effect of SCFA level and dietary quality on the risk of T2DM. Finally, an interaction was used to study the combined effect of SCFA levels and AHEI-2010 scores on T2DM. T2DM participants had lower levels of acetic and butyric acid. Generalised linear regression analysis revealed that the OR (95 % CI) of the highest acetic and butyric acid levels were 0·099 (0·022, 0·441) and 0·210 (0·057, 0·774), respectively, compared with the subjects with the lowest tertile of level. We also observed a significantly lower risk of T2DM with acetic acid levels > 1330·106 μg/g or butyric acid levels > 585·031 μg/g. Moreover, the risks of higher acetic and butyric acid levels of T2DM were 0·007 (95 % CI: 0·001, 0·148), 0·005 (95 % CI: 0·001, 0·120) compared with participants with lower AHEI-2010 scores (all P < 0·05). Acetate and butyrate levels may be important modifiable beneficial factors affecting T2DM in rural China. Improving dietary quality for body metabolism balance should be encouraged to promote good health.

Advancements in enhancing resistant starch type 3 (RS3) content in starchy food and its impact on gut microbiota: A review

Resistant starch type 3 (RS3), often found in cooked starchy food, has various health benefits due to its indigestible properties and physiological functions such as promoting the abundance of gut beneficial microbial flora and inhibiting the growth of intestinal pathogenic bacteria. However, it is challenging to develop starchy food with high RS3 content. This review aims to provide a detailed overview of current advancements to enhance RS3 content in starchy food and its effects of RS3 on gut microbiota. These approaches include breeding high-amylose cereals through gene editing techniques, processing, enzyme treatments, storage, formation of RS3 nanoparticles, and the incorporation of bioactive compounds. The mechanisms, specific conditions, advantages, and disadvantages associated with each approach and the potential effects of RS3 prepared by different methods on gut microbiota are summarized. In conclusion, this review contains important information that aims to provide guidelines for developing an efficient RS3 preparation process and promote the consumption of RS3-enriched starchy foods to improve overall health outcomes.

Green banana biomass anti-obesogenic, anti-hyperlipidemic, antidiabetic, and intestinal function potential effects: a systematic review

CONTEXT

Apparently, the consumption of resistant-starch food sources, such as green banana biomass, stimulates the proliferation of short-chain fatty acid intestinal bacteria producers, which can contribute to intestinal health and reduce the risk of chronic diseases. However, the available scientific evidence is scarce and no study has systematically evaluated such evidence.

OBJECTIVE

The aim of this study was to analyze the potential effects of green banana biomass on anthropometry, body composition, and biochemical and intestinal variables in humans and animals.

DATA SOURCES

The Cochrane Library, Embase, Medline/PubMed, Scopus, and Web of Science electronic databases were searched in January 2024 for eligible articles. Studies that tested the effects of cooked peeled or unpeeled green banana on anthropometric, biochemical, and/or intestinal variables were included.

DATA EXTRACTION

This systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The classification and assessment of the quality of studies were based on the relevant criteria related to the design of these studies and the quality criteria checklist of the Academy of Nutrition and Dietetics manual. Twelve studies published between 2001 and 2021 were included in the review.

DATA ANALYSIS

The results of human studies indicate that the ingestion of green banana biomass controlled intestinal dysfunction (50-300 g/day for 5-14 days or 30 g/day for 8 wk) in children, and showed potential anti-obesogenic, anti-hyperlipidemic, and antidiabetic (40 g/day for 24 wk) effects in adults. In rats, biomass consumption led to potential anti-obesogenic (25 g/day for 8 wk), anti-hyperlipidemic, and antidiabetic (∼8-30 g/day for 12 wk) effects.

CONCLUSION

Consumption of green banana biomass seems to exert beneficial effects on intestinal function and potential effects on obesity, dyslipidemia, and diabetes. These effects may be related to increased fecal short-chain fatty acid concentrations as a result of type 3 resistant starch present in biomass.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework (OSF) (https://doi.org/10.17605/OSF.IO/TKCWV).

Canna Starch Improves Intestinal Barrier Function, Inhibits Allergen Uptake, and Suppresses Anaphylactic Symptoms in Ovalbumin-Induced Food Allergy in Mice

Edible canna rhizomes contain extremely high levels of resistant starch among cereals and potatoes. We previously showed that feeding canna rhizome starch to mice may increase intestinal barrier function and improve the intestinal environment. Here, we investigated the effects of canna starch intake in a murine food allergy model. Five-week-old female BALB/c mice were divided into four groups: Control and OVA groups fed on the control diet (AIN-93G) ad libitum and Canna and OVA-Canna groups fed on the canna diet (AIN-93G with 10% replaced with canna starch). The OVA and OVA-Canna groups were sensitized to ovalbumin (OVA), and the anaphylactic response was assessed by measuring body temperature. Body temperature was significantly lower in the OVA group than in the non-sensitized group, but no decrease was observed in the OVA-Canna group. Fecal weight, fecal mucin content, and goblet cells of colorectal tissue were significantly increased in the Canna and OVA-Canna groups compared with those in the Control and OVA groups. Allergen uptake into the liver was also increased in the OVA group and decreased in the OVA-Canna group to the same level as in the non-sensitized group. These results indicate that canna starch supplementation in a murine food allergy model suppresses anaphylactic symptoms by improving the intestinal environment and reducing allergen uptake by increasing intestinal barrier function.

Addition of Canna edulis starch and starch nanoparticles to stabilized Pickering emulsions: In vitro digestion and fecal fermentation

Starch nanoparticles (SNPs) were prepared through acid hydrolysis of Canna edulis native starch and modified with octenyl succinic anhydride (OSA) to yield OS-starch and OS-SNPs. These modified particles were used to stabilize curcumin-loaded Pickering emulsions. Effects on gut microbiota during in vitro fecal fermentation were examined. The surface of OS-starch exhibits a porous structure, while OS-SNPs display layered grooves. OSA modification was confirmed by Fourier transform infrared spectroscopy (with peaks at 1728 cm-1 and 1573 cm-1) and proton nuclear magnetic resonance spectra (0.5-2 ppm). The degree of substitution for OS-starch and OS-SNPs is 0.0106 ± 0.0004 and 0.0079 ± 0.0003, respectively. Following modification, the crystallinity decreased from 35.69 ± 0.46 % (native starch) to 30.17 ± 0.70 % (OS-starch), SNPs decreased from 45.87 ± 0.89 % to 43.63 ± 0.64 % (OS-SNPs). Contact angles for OS-starch and OS-SNPs are 77.47 ± 1.78 and 55.57 ± 0.21, respectively. OS-SNPs exhibited superior emulsification properties compared to OS-starch, forming stable Pickering emulsions with pseudoplastic fluid behavior and enhanced curcumin storage protection over 14 days (60.88 ± 4.26 %) with controlled release. Stabilizing Pickering emulsions with OS-starch and OS-SNPs positively affected on gut microbiota and improved the intestinal environment, showing promise for their application in transportation systems and innovative prebiotic food formulations.

Nutrition at the Intersection between Gut Microbiota Eubiosis and Effective Management of Type 2 Diabetes

Nutrition is one of the most influential environmental factors in both taxonomical shifts in gut microbiota as well as in the development of type 2 diabetes mellitus (T2DM). Emerging evidence has shown that the effects of nutrition on both these parameters is not mutually exclusive and that changes in gut microbiota and related metabolites such as short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) may influence systemic inflammation and signaling pathways that contribute to pathophysiological processes associated with T2DM. With this background, our review highlights the effects of macronutrients, carbohydrates, proteins, and lipids, as well as micronutrients, vitamins, and minerals, on T2DM, specifically through their alterations in gut microbiota and the metabolites they produce. Additionally, we describe the influences of common food groups, which incorporate varying combinations of these macronutrients and micronutrients, on both microbiota and metabolic parameters in the context of diabetes mellitus. Overall, nutrition is one of the first line modifiable therapies in the management of T2DM and a better understanding of the mechanisms by which gut microbiota influence its pathophysiology provides opportunities for optimizing dietary interventions.

Extensive therapeutic effects, underlying molecular mechanisms and disease treatment prediction of Metformin: a systematic review

Metformin (Met), a first-line management for type 2 diabetes mellitus, has been expansively employed and studied with results indicating its therapeutic potential extending beyond glycemic control. Beyond its established role, this therapeutic drug demonstrates a broad spectrum of action encompassing over 60 disorders, encompassing metabolic conditions, inflammatory disorders, carcinomas, cardiovascular diseases, and cerebrovascular pathologies. There is clear evidence of Met's action targeting specific nodes in the molecular pathways of these diseases and, intriguingly, interactions with the intestinal microbiota and epigenetic processes have been explored. Furthermore, novel Met derivatives with structural modifications tailored to diverse diseases have been synthesized and assessed. This manuscript proffers a comprehensive thematic review of the diseases amenable to Met treatment, elucidates their molecular mechanisms, and employs informatics technology to prospect future therapeutic applications of Met. These data and insights gleaned considerably contribute to enriching our understanding and appreciation of Met's far-reaching clinical potential and therapeutic applicability.

Food and drug design for gut microbiota-directed regulation: Current experimental landscape and future innovation

Most diets and medications enhance host health via microbiota-dependent ways, but it is in the present situation of untargeted regulation. Non-targeted regulation may lead to the ineffectiveness of dietary supplements or drug treatment. Microbiota-directed food, aiming to improve diseases by targeting specific microbes without affecting other bacteria, have been proposed to deal with this problem. However, there is currently no universally applicable method to explore such foods or drugs. In this review, thirty studies on recent efforts in microbiota directed diets and medications are summarized from various databases. The methods used to find new foods and medications are primarily divided into four groups depending on the experimental models: in vivo and in vitro, as well as predictions based on bioinformatics. We also discuss their implementation, interpretation, and respective limitations, and describe the present situation. We further put forward a framework for microbiota-directed foods and medicine according to above methods and other microbiome manipulation, which will spur precision medicine.

Bile Acids and Short-Chain Fatty Acids Are Modulated after Onion and Apple Consumption in Obese Zucker Rats

Gut microorganisms are involved in the development and severity of different cardiovascular diseases, and increasing evidence has indicated that dietary fibre and polyphenols can interact with the intestinal microbiota. The study objective was to investigate the effect of onion and apple intake on the major types of microbial-derived molecules, such as short-chain fatty acids (SCFAs) and bile acids (BAs). Obese Zucker rats were randomly assigned (n = eight rats/group) to a standard diet (OC), a standard diet/10% onion (OO), or a standard diet/10% apple (OA). Lean Zucker rats fed a standard diet served as a lean control (LC) group. Faecal samples were collected at baseline, and 8 weeks later, the composition of the microbial community was measured, and BA and SCFA levels were determined using high-performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Rats fed onion- and apple-enriched diets had increased abundance of beneficial bacteria, such as Bifidobacterium spp. and Lactobacillus spp., enhanced SCFAs (acetic, propionic, isobutyric, and valeric acids), decreased excretion of some BAs, mainly of the primary (CA, α-MCA, and β-MCA) and secondary type (ω-MCA, HDCA, NCA, DCA, and LCA), and increased amount of taurine- and glycine-conjugated BAs compared to the OC group. The contribution of specific bioactive compounds and their metabolites in the regulation of the microbiome and the pathways linked to SCFA and BA formation and their relationship with some diseases needs further research.

Metabolism of resistant starch RS3 administered in combination with Lactiplantibacillus plantarum strain 84-3 by human gut microbiota in simulated fermentation experiments in vitro and in a rat model

This study aimed to investigate the metabolic and population responses of gut microbiota to resistant starch (RS3) in the presence of exogenous Lactiplantibacillus plantarum strain 84-3 (Lp84-3) in vitro and in vivo. Lp84-3 promoted acetate, propionate, and butyrate production from RS3 by gut microbiota and increased Lactobacillus and Blautia contents in vitro. Furthermore, in the presence of Lp84-3, starch granules presented a "dot-by-hole" fermentation pattern. Administration of Lp84-3 with RS3 increased the level of SCFA-producing Faecalibaculum, Parabacteroides, Alistipes, and Anaeroplasma in the faeces of rates, with Lactobacillus and Akkermansia representing the key genera that significantly promoted SCFAs, especially propionate and butyrate. Lp84-3 with RS3 promoted genes related to tryptophan synthase (EC 4.2.1.20) and beta-glucosidase (EC 3.2.1.21) in faecal bacteria. Our findings highlight the ability of Lp84-3 to enhance RS3 degradation, possibly by promoting SCFA-producing bacteria, and indicate that Lp84-3 could be a potential probiotic with a beneficial effect on gut microbiota.

The function, mechanisms, and clinical applications of metformin: potential drug, unlimited potentials

Metformin has been used clinically for more than 60 years. As time goes by, more and more miraculous effects of metformin beyond the clinic have been discovered and discussed. In addition to the clinically approved hypoglycemic effect, it also has a positive metabolic regulation effect on the human body that cannot be ignored. Such as anti-cancer, anti-aging, brain repair, cardiovascular protection, gastrointestinal regulation, hair growth and inhibition of thyroid nodules, and other nonclinical effects. Metformin affects almost the entire body in the situation taking it over a long period, and the preventive effects of metformin in addition to treating diabetes are also beginning to be recommended in some guidelines. This review is mainly composed of four parts: the development history of metformin, the progress of clinical efficacy, the nonclinical efficacy of metformin, and the consideration and prospect of its application.

Small molecule metabolites: discovery of biomarkers and therapeutic targets

Metabolic abnormalities lead to the dysfunction of metabolic pathways and metabolite accumulation or deficiency which is well-recognized hallmarks of diseases. Metabolite signatures that have close proximity to subject's phenotypic informative dimension, are useful for predicting diagnosis and prognosis of diseases as well as monitoring treatments. The lack of early biomarkers could lead to poor diagnosis and serious outcomes. Therefore, noninvasive diagnosis and monitoring methods with high specificity and selectivity are desperately needed. Small molecule metabolites-based metabolomics has become a specialized tool for metabolic biomarker and pathway analysis, for revealing possible mechanisms of human various diseases and deciphering therapeutic potentials. It could help identify functional biomarkers related to phenotypic variation and delineate biochemical pathways changes as early indicators of pathological dysfunction and damage prior to disease development. Recently, scientists have established a large number of metabolic profiles to reveal the underlying mechanisms and metabolic networks for therapeutic target exploration in biomedicine. This review summarized the metabolic analysis on the potential value of small-molecule candidate metabolites as biomarkers with clinical events, which may lead to better diagnosis, prognosis, drug screening and treatment. We also discuss challenges that need to be addressed to fuel the next wave of breakthroughs.

Ginsenoside Rb1 protects against diabetes-associated metabolic disorders in Kkay mice by reshaping gut microbiota and fecal metabolic profiles

ETHNOPHARMACOLOGICAL RELEVANCE

Panax quinquefolius Linn. is one of the most valuable herbal medicine in the world for its broad health benefits, including anti-diabetes. Ginsenoside Rb1, the principal active constituent of Panax quinquefolius Linn., could attenuate insulin resistance and metabolic disorders. The dysfunction of gut microbiota and fecal metabolites plays an important role in the pathogenesis of Type 2 Diabetes mellitus (T2DM). However, whether ginsenoside Rb1's hypoglycemic effect is related to gut microbiota remains elusive.

AIM OF THE STUDY

Our study aimed to explore the insulin-sensitizing and anti-diabetic effects of ginsenoside Rb1 as well as the underlying mechanisms.

MATERIALS AND METHODS

The T2DM model were established by high fat diet (HFD)-induced Kkay mice. The anti-diabetic effect of ginsenoside Rb1 (200 mg/kg/day) was evaluated by random blood glucose (RBG), fasting blood glucose (FBG), glucose tolerance test (OGTT), serum insulin level, insulin resistance index (HOMA-IR), pancreatic histology analysis, liver indexes, total triglyceride (TG) and total cholesterol (TC). Subsequently, 16S rRNA sequencing and LC-MS-based untargeted metabolomics were applied to characterize the microbiome and metabolites profile in HFD-induced Kkay mice, respectively. Finally, antibiotic treatment was used to validate the potential mechanism of ginsenoside Rb1 by modulating gut microbiota.

RESULTS

Our results showed that ginsenoside Rb1 reduced blood glucose, OGTT, serum insulin level, HOMA-IR, liver indexes as well as pancreatic injury. In addition, the ginsenoside Rb1 reversed the gut microbiota dysbiosis in diabetic Kkay mice, as indicated by the elevated abundance of Parasutterella, decreased population of Alistipes, f_Prevotellaceae_unclassified, Odoribacter, Anaeroplasma. Moreover, ginsenoside Rb1 altered free fatty acid (FFA) levels in fecal metabolites, such as decreased the level of α-linolenic acid, 13-OxoODE, oleic acid, 13-HODE, arachidonic acid, palmitic acid, stearic acid, while increased the level of PC (14:0/22:1(13Z)) and PC (16:0/16:0). Notably, ginsenoside Rb1 failed to improve HFD-induced diabetes in Kkay mice with antibiotics intervention.

CONCLUSION

These findings suggested that ginsenoside Rb1 may serve as a potential prebiotic agent to modulate specific gut microbes and related metabolites, which play essential roles in diabetes-associated metabolic disorders and insulin resistance.

Combined Gamma Conglutin and Lupanine Treatment Exhibits In Vivo an Enhanced Antidiabetic Effect by Modulating the Liver Gene Expression Profile

Previous studies have individually shown the antidiabetic potential of gamma conglutin (Cγ) and lupanine from lupins. Until now, the influence of combining both compounds and the effective dose of the combination have not been assessed. Moreover, the resulting gene expression profile from this novel combination remains to be explored. Therefore, we aimed to evaluate different dose combinations of Cγ and lupanine by the oral glucose tolerance test (OGTT) to identify the higher antidiabetic effect on a T2D rat model. Later, we administered the selected dose combination during a week. Lastly, we evaluated biochemical parameters and liver gene expression profile using DNA microarrays and bioinformatic analysis. We found that the combination of 28 mg/kg BW Cγ + 20 mg/kg BW lupanine significantly reduced glycemia and lipid levels. Moreover, this treatment positively influenced the expression of Pdk4, G6pc, Foxo1, Foxo3, Ppargc1a, Serpine1, Myc, Slc37a4, Irs2, and Igfbp1 genes. The biological processes associated with these genes are oxidative stress, apoptosis regulation, and glucose and fatty-acid homeostasis. For the first time, we report the beneficial in vivo effect of the combination of two functional lupin compounds. Nevertheless, further studies are needed to investigate the pharmacokinetics and pharmacodynamics of the Cγ + lupanine combined treatment.

Benefits of Huang Lian mediated by gut microbiota on HFD/STZ-induced type 2 diabetes mellitus in mice

BACKGROUND

Huang Lian (HL), one of the traditional Chinese medicines (TCMs) that contains multiple active components including berberine (BBR), has been used to treat symptoms associated with diabetes for thousands of years. Compared to the monomer of BBR, HL exerts a better glucose-lowering activity and plays different roles in regulating gut microbiota. However, it remains unclear what role the gut microbiota plays in the anti-diabetic activity of HL.

METHODS

In this study, a type 2 diabetes mellitus (T2DM) mouse model was induced with a six-week high-fat diet (HFD) and a one-time injection of streptozotocin (STZ, 75 mg/kg). One group of these mice was administrated HL (50 mg/kg) through oral gavage two weeks after HFD feeding commenced and continued for four weeks; the other mice were given distilled water as disease control. Comprehensive analyses of physiological indices related to glycolipid metabolism, gut microbiota, untargeted metabolome, and hepatic genes expression, function prediction by PICRUSt2 were performed to identify potential mechanism.

RESULTS

We found that HL, in addition to decreasing body fat accumulation, effectively improved insulin resistance by stimulating the hepatic insulin-mediated signaling pathway. In comparison with the control group, HL treatment constructed a distinct gut microbiota and bile acid (BA) profile. The HL-treated microbiota was dominated by bacteria belonging to Bacteroides and the Clostridium innocuum group, which were associated with BA metabolism. Based on the correlation analysis, the altered BAs were closely correlated with the improvement of T2DM-related markers.

CONCLUSION

These results indicated that the anti-diabetic activity of HL was achieved, at least partly, by regulating the structure of the gut microbiota and the composition of BAs.

Research Progress on Hypoglycemic Mechanisms of Resistant Starch: A Review

In recent years, the prevalence of diabetes is on the rise, globally. Resistant starch (RS) has been known as a kind of promising dietary fiber for the prevention or treatment of diabetes. Therefore, it has become a hot topic to explore the hypoglycemic mechanisms of RS. In this review, the mechanisms have been summarized, according to the relevant studies in the recent 15 years. In general, the blood glucose could be regulated by RS by regulating the intestinal microbiota disorder, resisting digestion, reducing inflammation, regulating the hypoglycemic related enzymes and some other mechanisms. Although the exact mechanisms of the beneficial effects of RS have not been fully verified, it is indicated that RS can be used as a daily dietary intervention to reduce the risk of diabetes in different ways. In addition, further research on hypoglycemic mechanisms of RS impacted by the RS categories, the different experimental animals and various dietary habits of human subjects, have also been discussed in this review.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

Amelioratory Effect of Resistant Starch on Non-alcoholic Fatty Liver Disease via the Gut-Liver Axis

Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome with a global prevalence. Impaired gut barrier function caused by an unhealthy diet plays a key role in disrupting the immune-metabolic homeostasis of the gut-liver axis (GLA), leading to NAFLD. Therefore, dietary interventions have been studied as feasible alternative therapeutic approaches to ameliorate NAFLD. Resistant starches (RSs) are prebiotics that reduce systemic inflammation in patients with metabolic syndrome. The present review aimed to elucidate the mechanisms of the GLA in alleviating NAFLD and provide insights into how dietary RSs counteract diet-induced inflammation in the GLA. Emerging evidence suggests that RS intake alters gut microbiota structure, enhances mucosal immune tolerance, and promotes the production of microbial metabolites such as short-chain fatty acids (SCFAs) and secondary bile acids. These metabolites directly stimulate the growth of intestinal epithelial cells and elicit GPR41/GPR43, FXR, and TGR5 signaling cascades to sustain immune-metabolic homeostasis in the GLA. The literature also revealed the dietary-immune-metabolic interplay by which RSs exert their regulatory effect on the immune-metabolic crosstalk of the GLA and the related molecular basis, suggesting that dietary intervention with RSs may be a promising alternative therapeutic strategy against diet-induced dysfunction of the GLA and, ultimately, the risk of developing NAFLD.

The crosstalk between gut microbiota, intestinal immunological niche and visceral adipose tissue as a new model for the pathogenesis of metabolic and inflammatory diseases: the paradigm of type 2 diabetes mellitus

Gut microbiota (GM) comprises more than one thousand microorganisms between bacterial species, viruses, fungi, and protozoa, and represents the main actor of a wide net of molecular interactions, involving, among others, the endocrine system, immune responses, and metabolism. GM influences many endocrine functions such as adrenal steroidogenesis, thyroid function, sexual hormones, IGF-1 pathway and peptides produced in gastrointestinal system. It is fundamental in glycaemic control and obesity, while also exerting an important function in modulating the immune system and associated inflammatory disease. The result of this crosstalk in gut mucosa is the formation of the intestinal immunological niche. Visceral adipose tissue (VAT) produces about 600 different peptides, it is involved in lipid and glucose metabolism and in some immune reactions through several adipokines. GM and VAT interact in a bidirectional fashion: while gut dysbiosis can modify VAT adipokines and hormone secretion, VAT hyperplasia modifies GM composition. Acquired or genetic factors leading to gut dysbiosis or increasing VAT (i.e., Western diet) induce a proinflammatory condition, which plays a pivotal role in the development of dysmetabolic and immunologic conditions, such as diabetes mellitus. Diabetes is clearly associated with specific patterns of GM alterations, with an abundance or reduction of GM species involved in controlling mucosal barrier status, glycaemic levels and exerting a pro- or anti-inflammatory activity. All these factors could explain the higher incidence of several inflammatory conditions in Western countries; furthermore, besides the specific alterations observed in diabetes, this paradigm could represent a common pathway acting in many metabolic conditions and could pave the way to a new, interesting therapeutic approach.

Effects of Alkaloid-Rich Extracts Obtained from Grifola frondosa on Gut Microbiota and Glucose Homeostasis in Rats

Grifola frondosa (GF), also known as maitake (a type of mushroom), has been widely used as a food item and it exhibits various health-beneficial hypoglycemic activities. Rats fed with a...

Type 3 resistant starch from Canna edulis modulates obesity and obesity-related low-grade systemic inflammation in mice by regulating gut microbiota composition and metabolism

Obesity is a most prevalent human health problem. Several studies showed that appropriate modulation of gut microbiota could help reshape the metabolic profile of obese individuals, thereby altering the development of obesity. A nutritional strategy for treating obesity includes prebiotics. Type 3 Resistant Starch from Canna edulis (Ce-RS3) is a dietary fiber that exerts potential effects on the intestinal microbial community; however, the metabolic landscape and anti-obesity mechanism remain unclear. In the present study, obese mice were treated with Ce-RS3, and 16S rRNA gene sequencing and metabolomics were used to measure changes in gut microbiota and fecal metabolic profiles, respectively. At the end of the treatment (13 weeks), we observed slow weight gain in the mice, and pathological damage and inflammation were substantially reduced. Ce-RS3 constructs a healthy gut microbiota structure and can enhance intestinal immunity and reduce metabolic inflammation. Ce-RS3 increased the diversity of gut microbiota with enrichment of Bifidobacterium and Roseburia. Ce-RS3 regulated the systemic metabolic dysbiosis in obese mice and adjusted 26 abnormal metabolites in amino acids and lipids metabolism, many of which are related to the microbiome. More importantly, we found that the anti-obesity effect of Ce-RS3 can be transferred by fecal transplantation. The beneficial effects of Ce-RS3 might derive from gut microbiota changes, which might improve obesity and metabolic inflammation by altering host-microbiota interactions with impacts on the metabolome. In conclusion, Ce-RS3 can be used as a prebiotic with potential value for the treatment of obesity.

Exposure to a mixture of cigarette smoke carcinogens disturbs gut microbiota and influences metabolic homeostasis in A/J mice

An increased risk of developing lung cancer has been associated with exposure to cigarette smoke carcinogens and alteration in the gut microbiota. However, there is limited understanding about the impact of exposure to NNK and BaP, the two important components of cigarette smoke carcinogens, on gut microbiota in lung cancer. The present study characterized the influence of exposure to a mixture of NNK plus BaP on lung cancer, feces metabolite composition, and gut microbiota in the A/J mice. The A/J mice were administered NNK plus BaP, and the changes in gut microbiota and feces metabolic profiles were characterized using 16S rRNA gene sequencing and metabolomics, respectively. Results presented here illustrated that a mixture of NNK plus BaP exposure triggered lung carcinogenesis as shown by light microscopy and histopathological evaluation. 16S rRNA sequencing of gut microbiota indicated that exposure to NNK plus BaP could modified fecal bacterial composition. Elevated levels of Actinobacteria, Bifidobacterium, and Intestinimonas and reduced levels of Alistipes, Odoribacter, and Acetatifactor are associated with NNK plus BaP triggered lung cancer. In addition, metabolomics profile revealed the regulation of metabolism including purine metabolism, phenylalanine metabolism, primary bile acid biosynthesis, steroid hormone biosynthesis, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and others. In conclusion, the results provide some guidance for using gut microbes as biomarkers to assess the progression of lung cancer, and lead to interventional targets to control the development of the disease in the future.

Preparation, structure characterization, and specific gut microbiota properties related to anti-hyperlipidemic action of type 3 resistant starch from Canna edulis

Type 3 resistant starch (RS3) was developed from Canna edulis (Ce) native starch (NS) through dual enzymatic hydrolysis and recrystallization. Thereafter, the processed Ce-RS3 was subjected to systematic characterizations for its structural properties, anti-hyperlipidemic effect, and in vivo gut microbiota modulatory function. The Ce-RS3 content was increased to 49.11% after processing under optimal conditions. Compared with NS, Ce-RS3 maintained its B-type crystallization without introducing new chemical groups. Meanwhile, it displayed coarse surfaces, higher crystallinity, more ordered structures, and a higher proportion of chains with degree of polymerization (DP) 37-100. Ce-RS3 intervention significantly alleviated dyslipidemia in hyperlipidemic mice, which was associated with increased gut microbial diversity and unique microbial enrichment, potentially mediated by its fine structure. These observations are valuable for developing RS3 from C. edulis for prebiotics applications and support the potential strategy that utilizes well-designed RS to modulate specific bacterial populations to improve health.

Efficacy of metformin and fermentable fiber combination therapy in adolescents with severe obesity and insulin resistance: study protocol for a double-blind randomized controlled trial

Background

Accumulating evidence suggests that the metabolic effects of metformin and fermentable fibers are mediated, in part, through diverging or overlapping effects on the composition and metabolic functions of the gut microbiome. Pre-clinical animal models have established that the addition of fiber to metformin monotherapy improves glucose tolerance. However, possible synergistic effects of combination therapy (metformin plus fiber) have not been investigated in humans. Moreover, the underlying mechanisms of synergy have yet to be elucidated. The aim of this study is to compare in adolescents with obesity the metabolic effects of metformin and fermentable fibers in combination with those of metformin or fiber alone. We will also determine if therapeutic responses correlate with compositional and functional features of the gut microbiome.

Methods

This is a parallel three-armed, double-blinded, randomized controlled trial. Adolescents (aged 12–18 years) with obesity, insulin resistance (IR), and a family history of type 2 diabetes mellitus (T2DM) will receive either metformin (850 mg p.o. twice/day), fermentable fibers (35 g/day), or a combination of metformin plus fiber for 12 months. Participants will be seen at baseline, 3, 6, and 12 months, with a phone follow-up at 1 and 9 months. Primary and secondary outcomes will be assessed at baseline, 6, and 12 months. The primary outcome is change in IR estimated by homeostatic model assessment of IR; key secondary outcomes include changes in the Matsuda index, oral disposition index, body mass index z-score, and fat mass to fat-free mass ratio. To gain mechanistic insight, endpoints that reflect host-microbiota interactions will also be assessed: obesity-related immune, metabolic, and satiety markers; humoral metabolites; and fecal microbiota composition, short-chain fatty acids, and bile acids.

Discussion

This study will compare the potential metabolic benefits of fiber with those of metformin in adolescents with obesity, determine if metformin and fiber act synergistically to improve IR, and elucidate whether the metabolic benefits of metformin and fiber associate with changes in fecal microbiota composition and the output of health-related metabolites. This study will provide insight into the potential role of the gut microbiome as a target for enhancing the therapeutic efficacy of emerging treatments for T2DM prevention.

Trial registration

ClinicalTrials.gov NCT04578652. Registered on 8 October 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05060-8.

Rubidium chloride modulated the fecal microbiota community in mice

Background

The microbiota plays an important role in host health. Although rubidium (Rb) has been used to study its effects on depression and cancers, the interaction between microbial commensals and Rb is still unexplored. To gain the knowledge of the relationship between Rb and microbes, 51 mice receiving RbCl-based treatment and 13 untreated mice were evaluated for their characteristics and bacterial microbiome changes.

Results

The 16S ribosomal RNA gene sequencing of fecal microbiota showed that RbCl generally maintained fecal microbial community diversity, while the shifts in fecal microbial composition were apparent after RbCl exposure. RbCl significantly enhanced the abundances of Rikenellaceae, Alistipes, Clostridium XlVa and sulfate-reducing bacteria including Deltaproteobacteria, Desulfovibrionales, Desulfovibrionaceae and Desulfovibrio, but significantly inhibited the abundances of Tenericutes, Mollicutes, Anaeroplasmatales, Anaeroplasmataceae and Anaeroplasma lineages. With regarding to the archaea, we only observed two less richness archaea Sulfolobus and Acidiplasma at the genus level.

Conclusions

Changes of fecal microbes may in part contribute to the anticancer or anti-depressant effects of RbCl. These findings further validate that the microbiome could be a target for therapeutic intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02095-4.