Effect of whole-grain Tartary buckwheat fermentation with Monascus purpureus on the metabolic syndrome and intestinal flora in mice

Abstract

This study investigated changes in the composition of fermented whole-grain Tartary buckwheat (FTB) by Monascus purpureus and the therapeutic effects of FTB on metabolic diseases in mice fed high-fat and high-sugar (HFHS) diets. Compared to raw Tartary Buckwheat (RTB), the protein, total phenol, and total flavonoid contents of FTB were significantly increased by 67.88%, 24.97%, and 45.74%, respectively, especially the rutin content reached 2607.31 mg/100g DW (p < 0.05, p < 0.01, p < 0.0001). Meanwhile, it exhibits stronger antioxidant properties of DPPH, ABTS, and FRAP (p < 0.05, p < 0.01). Then, the treatment of low (3 g/kg), medium (6 g/kg), and high (12 g/kg) doses of FTB (FL, FM, FH) could positively regulate weight, blood lipids, pro-inflammatory factors, glucose tolerance, and liver damage in HFHS mice. Among all groups, the levels of weight (35.53 g), fat (0.93 g/100 g), TG (0.77 mmol/L), IL-1β (84.77 ng/L), IL-6 (127.62 pg/L) and insulin (7.06 mIU/L) of serum, IL-1β (74.89 ng/L) and TNF-α (840.32 pg/L) of liver were all the lowest in FH group. Furthermore, the intestinal flora compositions were positively regulated by FTB treatment, including reducing the relative abundance of harmful bacteria (Clostridia_UCG-014, Candidatus_Saccharimonas, and Enterorhabdus) and enhancing the relative abundance of beneficial bacteria (Akkermansia and Eubacterium coprostanoligenes). Particularly, the phyla Firmicutes/Bacteroidetes (F/B) ratio was markedly restored and the abundance of Akkermansia and Eubacterium coprostanoligenes was significantly increased in the FH group (p < 0.0001). In conclusion, FTB can be used as a dietary supplement for improving metabolic syndrome and intestinal flora disorders. This study provides new ideas for the use of whole-grain Tartary buckwheat, new product development, and industry chain enhancement.