The objective of this study is to assess the potential anti-
obesity effects of black garlic
melanoidins (MLDs) and gut microbiota changes in an animal model, hypothesizing that the effects of
oral administration of MLDs can be partially mediated by the modulation of intestinal microbiota via inhibiting the formation of
lipopolysaccharides (LPS) and promoting the production of
short-chain fatty acids (SCFAs). The effects of MLDs in C57BL/6J mice with high-fat diet (HFD)-induced
obesity were investigated for 12 weeks with low (50 mg kg-1 day-1), medium (100 mg kg-1 day-1) and high (200 mg kg-1 day-1) doses. The results indicated that
oral administration of MLDs markedly reduced high fat diet-induced
weight gain and white adipose tissue weights and reversed
glucose tolerance, especially at high doses. Besides, MLDs could alleviate dyslipidaemia, significantly suppress hepatic
lipid accumulation and steatosis and effectively ameliorate lipid metabolism. The plasma LPS reduced significantly and the SCFAs increased in a dose-dependent manner. The MLDs could down-regulate the expression of
fatty acid synthase (FAS) and
interleukin-6 (IL-6) and up-regulate the expression of adipose triacylglyceride
lipase (ATGL) and
hormone sensitive lipase (HSL) in adipose tissues and livers at
mRNA levels. Moreover, after the
oral administration of MLDs, the intestinal microbial environment improved in the sense that bacterial diversity and richness increased. Intervention with MLDs modified the gut microbiota in mice with HFD-induced
obesity, increasing the number of SCFA-producing bacteria (Bacteroidaceae) and reducing opportunistic pathogens (Enterobacteriaceae and Desulfovibrionaceae). An increased abundance of other probiotics including Lactobacillaceae and Akkermansiaceae was also observed. In conclusion, MLDs could improve
glucose tolerance, induce the production of SCFAs and inhibit the production of
endotoxin LPS, most likely mediated by modulating the gut microbiota. Therefore, it seems that MLDs exhibit anti-
obesity effects and might be used as potential agents against
obesity.