Limosilactobacillus reuteri fermentation enhances the anti-type 2 diabetic activity of Gastrodia elata polysaccharides.

Abstract

The development of effective and low-toxicity treatments for type 2 diabetes mellitus (T2DM) remains a critical objective in current research. Lactic acid bacteria (LAB) fermentation can biotransform plant polysaccharides and may enhance their bioactivity. Here, we investigated the fermentation with Limosilactobacillus reuteri DSM17938 fermentation affects the structure of Gastrodia elata polysaccharides and their potentail benefits in T2DM. Polysaccharides were extracted from non-fermented G. elata (GP) and from G. elata fermented with L. reuteri DSM 17,938 under controlled conditions to yield fermented polysaccharides (LGP). Fermentation reduced molecular weight and shifted monosaccharide composition, including increased content of galactose, arabinose, glucose, xylose, and galacturonic acid while decreased content of fructose. Fermentation reduced the molecular weight, altered the morphology, and shifted the monosaccharide composition, including increased content of arabinose and galacturonic acid while decreasing fructose. In a T2DM mouse model, LGP (10.9 ± 0.8 mmol/L) demonstrated a more significant hypoglycemic effect compared to GP (14.6 ± 1.4 mmol/L, p < 0.001). Furthermore, LGP more effectively improved antioxidant and inflammatory profiles markers (p < 0.001), and attenuated intestine and kidney injury. Mechanistic investigations revealed that LGP modulates gut microbiota composition by reducing the Firmicutes/Bacteroidetes ratio and promoting the proliferation of beneficial bacteria such as Kineothrix and Akkermansia, while concurrently increasing short-chain fatty acid levels and regulating serum metabolic pathways related to carbohydrate and protein digestion and absorption. This study demonstrates that LAB fermentation is an effective bioprocessing strategy for enhancing the hypoglycemic activity of GPs, offering novel insights for the production of functional foods.