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.

Primary and secondary metabolites produced in Salvia miltiorrhiza hairy roots by an endophytic fungal elicitor from Mucor fragilis.

Salvia miltiorrhiza is one of the most commonly used medicinal materials in China. In recent years, the quality of S. miltiorrhiza has attracted much attention. Biotic and abiotic elicitors are widely used in cultivation to improve the quality of medicinal plants. We isolated an endophytic fungus, Mucor fragilis, from S. miltiorrhiza. We compared the effects of endophytic fungal elicitors with those of yeast extract together with silver ion, widely used together as effective elicitors, on S. miltiorrhiza hairy roots. Seventeen primary metabolites (amino acids and fatty acids) and five secondary metabolites (diterpenoids and phenolic acids) were analyzed after elicitor treatment. The mycelium extract promoted the accumulation of salvianolic acid B, rosmarinic acid, stearic acid, and oleic acid in S. miltiorrhiza hairy roots. Additionally, qPCR revealed that elicitors affect the accumulation of primary and secondary metabolites by regulating the expression of key genes (SmAACT, SmGGPPS, and SmPAL). This is the first detection of both the primary and secondary metabolites of S. miltiorrhiza hairy roots, and the results of this work should help guide the quality control of S. miltiorrhiza. In addition, the findings confirm that Mucor fragilis functions as an effective endophytic fungal elicitor with excellent application prospect for cultivation of medicinal plants.