Effect of (D)-fagomine on excreted Enterobacteria and weight gain in rats fed a high-fat high-sucrose diet

Evaluation and development of a novel pre-treatment method for mulberry leaves to enhance their bioactivity via enzymatic degradation of GAL-DNJ to DNJ

Mulberry leaves are rich in 1-deoxynojirimycin (DNJ) and 2-O-α-D-galactopyranosyl-deoxynojirimycin (GAL-DNJ). Compared to DNJ, the bioactive potency of GAL-DNJ is low. We proposed that the conversion of GAL-DNJ into DNJ may improve its bioavailability. We evaluated this hypothesis and constructed a novel enzymatic-based method to induce the hydrolysis of GAL-DNJ to DNJ in order to improve the therapeutic potency of mulberry leaves.

A comprehensive review on the production, pharmacokinetics and health benefits of mulberry leaf iminosugars: Main focus on 1-deoxynojirimycin, d-fagomine, and 2-O-ɑ-d-galactopyranosyl-DNJ

Mulberry leaves are rich in biologically active compounds, including phenolics, polysaccharides, and alkaloids. Mulberry leaf iminosugars (MLIs; a type of polyhydroxylated alkaloids), in particular, have been gaining increasing attention due to their health-promoting effects, including anti-diabetic, anti-obesity, anti-hyperglycemic, anti-hypercholesterolemic, anti-inflammatory, and gut microbiota-modulatory activities. Knowledge regarding the in vivo bioavailability and bioactivity of MLIs are crucial to understand their role and function and human health. Therefore, this review is aimed to comprehensively summarize the existing studies on the oral pharmacokinetics and the physiological significance of selected MLIs (i.e.,1-deoxynojirimycin, d-fagomine, and 2-O-ɑ-d-galactopyranosyl-DNJ). Evidence have suggested that MLIs possess relatively good uptake and safety profiles, which support their prospective use for oral intake; the therapeutic potential of these compounds against metabolic and chronic disorders and the underlying mechanisms behind these effects have also been studied in in vitro and in vivo models. Also discussed are the biosynthetic pathways of MLIs in plants, as well as the agronomic and processing factors that affect their concentration in mulberry leaves-derived products.

Poria cocos could ameliorate cognitive dysfunction in APP/PS1 mice by restoring imbalance of Aβ production and clearance and gut microbiota dysbiosis

Alzheimer's disease (AD) is the most common neurodegenerative disorder. Amyloid beta-protein (Aβ) plaques, which are the hallmark of AD, are formed from the imbalance of Aβ production and clearance accompanied by neuroinflammation, gut dysbiosis, and metabolite dysfunction. All of these processes give rise to neurochemical deficiencies and synaptic dysfunction, which ultimately contribute to recognition dysfunction. Poria cocos (PC), which contains multiple active ingredients, plays a significant role in the treatment of multiple-pathogenesis senile diseases such as AD. Nevertheless, there are only very few investigations on the intricate action mechanism of PC for the treatment of AD. In this study, we evaluate the multi-target cure effect of PC on APP/PS1 mice by behavioral, immunohistochemical (IHC), targeted metabolomics, and 16S rRNA sequencing experiments. Mice treated with PC showed significant improvements in cognitive function as evaluated by the behavioral experiment. IHC revealed that PC treatment relieved Aβ deposition by reducing the formation of Aβ and increasing its clearance. Moreover, PC treatment improved gut dysbiosis, which reversed the metabolite dysfunction of bile acid. These findings reveal that PC is a promising therapeutic agent, which might ameliorate the cognitive function of AD by restoring the imbalance of Aβ production and clearance and gut microbiota dysbiosis.

In vitro colonic fermentation profiles and microbial responses of propionylated high-amylose maize starch by individual Bacteroides-dominated enterotype inocula

The concept of "enterotype" has been proposed to differentiate the gut microbiota between individual humans, and different dominant bacteria utilize fiber substrates with different fermentation properties and microbial changes. In this study, we made propionylated high-amylose maize starch and investigated both in vitro fecal fermentation properties and microbial responses by individual Bacteroides-dominated enterotype inocula. Propionyl group substitution of HAMS did not significantly change gas production profiles, suggesting that the gas production during fermentation is independent of propionylation. The final concentration of released propionate significantly increased (10.26-12.60 mM) as a function of propionylation degree, suggesting that the introduced propionyl groups can increase the concentration of short-chain fatty acids (SCFA) during colonic fermentation. At the genus level, Bacteroides was obviously promoted for all donors with the final abundance in the range of 0.1-0.24, indicating that propionylated high-amylose maize starch changed the structure and abundance of microbiota compared to unmodified starch. Besides, the non-metric dimensional scoring (NMDS) plots showed that those changes were related to the initial microbiota composition. The results may offer useful information for the design of personalized food products and relevant therapies at least within Bacteroides-dominated enterotype.

A cascade reaction for the synthesis of d-fagomine precursor revisited: Kinetic insight and understanding of the system

The synthesis of aldol adduct (3S,4R)-6-[(benzyloxycarbonyl)amino]-5,6-dideoxyhex-2-ulose, a precursor of the interesting dietary supplement, iminosugar d-fagomine, was studied in a cascade reaction with three enzymes starting from Cbz-N-3-aminopropanol. This system was studied previously using a statistical optimization method which enabled a 79 % yield of the aldol adduct with a 10 % yield of the undesired amino acid by-product. Here, a kinetic model of the cascade, including enzyme operational stability decay rate and the undesired overoxidation of the intermediate product, was developed. The validated model was instrumental in the optimization of the cascade reaction in the batch reactor. Simulations were carried out to determine the variables with the most significant impact on substrate conversion and product yield. As a result, process conditions were found that provided the aldol adduct in 92 % yield with only 0.7 % yield of the amino acid in a one-pot one-step reaction. Additionally, compared to previous work, this improved process outcome was achieved at lower concentrations of two enzymes used in the reaction. With this study the advantages are demonstrated of a modelling approach in developing complex biocatalytical processes. Mathematical models enable better understanding of the interactions of variables in the investigated system, reduce cost, experimental efforts in the lab and time necessary to obtain results since the simulations are carried out in silico.

Dietary Components, Microbial Metabolites and Human Health: Reading between the Lines

Trillions of bacteria reside in the human gut and they metabolize dietary substances to obtain nutrients and energy while producing metabolites. Therefore, different dietary components could affect human health in various ways through microbial metabolism. Many such metabolites have been shown to affect human physiological activities, including short-chain fatty acids metabolized from carbohydrates; indole, kynurenic acid and para-cresol, metabolized from amino acids; conjugated linoleic acid and linoleic acid, metabolized from lipids. Here, we review the features of these metabolites and summarize the possible molecular mechanisms of their metabolisms by gut microbiota. We discuss the potential roles of these metabolites in health and diseases, and the interactions between host metabolism and the gut microbiota. We also show some of the major dietary patterns around the world and hope this review can provide insights into our eating habits and improve consumers' health conditions.

Effects of combined D-fagomine and omega-3 PUFAs on gut microbiota subpopulations and diabetes risk factors in rats fed a high-fat diet

Food contains bioactive compounds that may prevent changes in gut microbiota associated with Westernized diets. The aim of this study is to explore the possible additive effects of D-fagomine and ω-3 PUFAs (EPA/DHA 1:1) on gut microbiota and related risk factors during early stages in the development of fat-induced pre-diabetes. Male Sprague Dawley (SD) rats were fed a standard diet, or a high-fat (HF) diet supplemented with D-fagomine, EPA/DHA 1:1, a combination of both, or neither, for 24 weeks. The variables measured were fasting glucose and glucose tolerance, plasma insulin, liver inflammation, fecal/cecal gut bacterial subgroups and short-chain fatty acids (SCFAs). The animals supplemented with D-fagomine alone and in combination with ω-3 PUFAs accumulated less fat than those in the non-supplemented HF group and those given only ω-3 PUFAs. The combined supplements attenuated the high-fat-induced incipient insulin resistance (IR), and liver inflammation, while increasing the cecal content, the Bacteroidetes:Firmicutes ratio and the populations of Bifidobacteriales. The functional effects of the combination of D-fagomine and EPA/DHA 1:1 against gut dysbiosis and the very early metabolic alterations induced by a high-fat diet are mainly those of D-fagomine complemented by the anti-inflammatory action of ω-3 PUFAs.

Combined Buckwheat d-Fagomine and Fish Omega-3 PUFAs Stabilize the Populations of Gut Prevotella and Bacteroides While Reducing Weight Gain in Rats

Some functional food components may help maintain homeostasis by promoting balanced gut microbiota. Here, we explore the possible complementary effects of d-fagomine and ω-3 polyunsaturated fatty acids (ω-3 PUFAs) eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA 1:1) on putatively beneficial gut bacterial strains. Male Sprague–Dawley rats were supplemented with d-fagomine, ω-3 PUFAs, or both, for 23 weeks. Bacterial subgroups were evaluated in fecal DNA by quantitative real-time polymerase chain reaction (qRT-PCR) and short-chain fatty acids were determined by gas chromatography. We found that the populations of the genus Prevotella remained stable over time in animals supplemented with d-fagomine, independently of ω-3 PUFA supplementation. Animals in these groups gained less weight than controls and rats given only ω-3 PUFAs. d-Fagomine supplementation together with ω-3 PUFAs maintained the relative populations of Bacteroides. ω-3 PUFAs alone or combined with d-fagomine reduced the amount of acetic acid and total short-chain fatty acids in feces. The plasma levels of pro-inflammatory arachidonic acid derived metabolites, triglycerides and cholesterol were lower in both groups supplemented with ω-3 PUFAs. The d-fagomine and ω-3 PUFAs combination provided the functional benefits of each supplement. Notably, it helped stabilize populations of Prevotella in the rat intestinal tract while reducing weight gain and providing the anti-inflammatory and cardiovascular benefits of ω-3 PUFAs.

A Systematic Review of the Medicinal Potential of Mulberry in Treating Diabetes Mellitus

Diabetes mellitus (DM) is a serious metabolic disorder which has reached epidemic proportions all over the world. Despite tremendous developments in medicinal chemistry, traditional medicine is still commonly used for the prevention and treatment of DM. Traditional herbal medicines have played a major role in the management of DM in Asian countries. In particular, mulberry has commonly been utilized in China for the treatment of DM for thousands of years. In the last decade, numerous preclinical findings have suggested that mulberry is a promising therapeutic agent for the treatment of DM, and the polyhydroxylated alkaloids, flavonoids and polysaccharides from mulberry may be the potential active components. The present review systematically summarizes the chemical composition of mulberry and the pharmacological effects of different medicinal parts on DM; these effects include influences on glucose absorption, insulin (INS) production/secretion, anti-oxidation and anti-inflammation processes. After summarizing our research findings, we will discuss the challenges and opportunities and explore the direction of future research and the potential for developing mulberry into pharmaceuticals for the widespread treatment of DM.

A combination of quercetin and resveratrol reduces obesity in high-fat diet-fed rats by modulation of gut microbiota

Resveratrol and quercetin, widely found in foods and vegetables, are plant polyphenols reported to have a wide range of biological activities. Despite their limited bioavailabilities, both resveratrol and quercetin are known to exhibit anti-inflammation and anti-obesity effects. We hypothesized that gut microbiota may be a potential target for resveratrol and quercetin to prevent the development of obesity. The aim of this research was to confirm whether a combination of quercetin and resveratrol (CQR) could restore the gut microbiota dysbiosis induced by a high-fat diet (HFD). In this study, Wistar rats were divided into three groups: a normal diet (ND) group, a HFD group and a CQR group. The CQR group was treated with a HFD and administered with a combination of quercetin [30 mg per kg body weight (BW) per day] and resveratrol [15 mg per kg body weight (BW) per day] by oral gavage. At the end of 10 weeks, CQR reduced the body weight gain and visceral (epididymal, perirenal) adipose tissue weight. Moreover, CQR also reduced serum lipids, attenuated serum inflammatory markers [interleukin (IL)-6, tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1] and reversed serum biochemical parameters (adiponectin, insulin, leptin, etc.). Importantly, our results demonstrated that CQR could modulate the gut microbiota composition. 16S rRNA gene sequencing revealed that CQR had an impact on gut microbiota, decreasing Firmicutes (P < 0.05) and the proportion of Firmicutes to Bacteroidetes (P = 0.052). CQR also significantly inhibited the relative abundance of Desulfovibrionaceae (P < 0.01), Acidaminococcaceae (P < 0.05), Coriobacteriaceae (P < 0.05), Bilophila (P < 0.05), Lachnospiraceae (P < 0.05) and its genus Lachnoclostridium (P < 0.001), which were reported to be potentially related to diet-induced obesity. Moreover, compared with the HFD group, the relative abundance of Bacteroidales_S24-7_group (P < 0.01), Christensenellaceae (P < 0.001), Akkermansia (P < 0.01), Ruminococcaceae (P < 0.01) and its genera Ruminococcaceae_UCG-014 (P < 0.01), and Ruminococcaceae_UCG-005 (P < 0.01), which were reported to have an effect of relieving HFD-induced obesity, was markedly increased in the CQR group. Overall, these results indicated that administration of CQR may have beneficial effects on ameliorating HFD-induced obesity and reducing HFD-induced gut microbiota dysbiosis.

Fate of d-Fagomine after Oral Administration to Rats

d-Fagomine is an iminosugar found in buckwheat that is capable of inhibiting the adhesion of potentially pathogenic bacteria to epithelial mucosa and reducing the postprandial blood glucose concentration. This paper evaluates the excretion and metabolism of orally administered d-fagomine in rats and compares outcomes with the fate of 1-deoxynojirimycin. d-Fagomine and 1-deoxynojirimycin show similar absorption and excretion kinetics. d-Fagomine is partly absorbed (41-84%, dose of 2 mg/kg of body weight) and excreted in urine within 8 h, while the non-absorbed fraction is cleared in feces within 24 h. d-Fagomine is partially methylated (about 10% in urine and 3% in feces). The concentration of d-fagomine in urine from 1 to 6 h after administration is higher than 10 mg/L, the concentration that inhibits adhesion of Escherichia coli. Orally administered d-fagomine is partially absorbed and then rapidly excreted in urine, where it reaches a concentration that may be protective against urinary tract infections.

d-Fagomine attenuates metabolic alterations induced by a high-energy-dense diet in rats

d-Fagomine attenuates the negative effects of a high-energy-dense diet on plasma glucose, triglycerides and metabolic hormones, as well as on weight gain in rats.