Analysis of the alleviating effect of black bean peel anthocyanins on type 2 diabetes based on gut microbiota and serum metabolome

Black bean peel is rich in various nutrients and exerts therapeutic effects on type 2 diabetes mellitus (T2DM); however, its therapeutic mechanism is still unclear. This study investigated the therapeutic mechanism of black bean peel anthocyanin extract on T2DM from the perspective of gut microbiota and serum metabolome. The black bean peel anthocyanin extract improved blood glucose, oxidative stress and inflammatory responses, and alleviated lipid metabolism disorders in T2DM rats. The abundance of Akkermansia spp., Bacteroidetes spp., Phascolarctobacterium spp., and Turicibacterium spp. were increased in the gut, and the levels of bilirubin, glycocholic acid, lithocholic acid, and glycochenodeoxycholate were increased in serum. The qPCR and western blot results showed that the black bean peel anthocyanin extract improved T2DM and lipid metabolism by regulating the expression of LXR, LKB1, and SREBP-1c. These results provided a new therapeutic direction for T2DM treatment.