Abstract: This study isolated and identified a probiotic strain with hypoglycemic activity from naturally fermented sugarcane residue. The inhibitory effects of the strain and its cell-free supernatant against key digestive enzymes were assessed along with hypoglycemic effects in a mouse model of type 2 diabetes mellitus induced by a high-fat diet and streptozotocin. The results showed that six strains of Lactiplantibacillus plantarum were obtained from naturally fermented sugarcane residue. Among them, the cell-free supernatant of L. plantarum P6 inhibited 96.49% of α-glucosidase activity. The in vivo experiment showed that L. plantarum P6 and its cell-free supernatant could effectively alleviate symptoms such as excessive drinking, eating, and urination, as well as body mass loss and organ enlargement in mice. It could also significantly rescue glucose tolerance and abnormal insulin secretion, effectively reduce the serum levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, and inflammatory factors (interleukin (IL)-6, IL-10, tumor necrosis factor-α, and lipopolysaccharide), and promote the secretion of high-density lipoprotein cholesterol and glucagon-like peptide-1. Therefore, L. plantarum P6 and its cell-free supernatant have the potential to significantly reduce blood sugar levels and mitigate diabetes-related symptoms.

Key words: Lactiplantibacillus plantarum; cell-free supernatant; α-glucosidase; hypoglycemic ability; type 2 diabetes mellitus