Transformation of mulberry polyphenols by Lactobacillus plantarum SC-5: Increasing phenolic acids and enhancement of anti-aging effect.

Fermentation can transform bioactive compounds in food and improve their biological activity. This study aims to explore the transformation of polyphenols in mulberry juice and the improvement of its anti-aging effect. The results demonstrated that Lactobacillus plantarum SC-5 transformed anthocyanin in mulberry juice into more phenolic acids, especially improved 2-hydroxy-3-(4-hydroxyphenyl) propanoic acid from 4.16 ± 0.06 to 10.07 ± 0.03. In the D-gal-induced mouse model, fermented mulberry juice significantly raised the abundance of Bifidobacteriaceae (303.7 %) and Lactobacillaceae (237.2 %) and Short-chain fatty acids (SCFAs) in intestine, further reducing the level of oxidative stress (12.3 %). Meanwhile, the expression of Sirtuin 1 (SIRT1) and Brain-derived neurotrophic factor (BDNF) increased, which protected the integrity of hippocampal tissue. Morris water maze results approved that fermented mulberry juice improved cognitive ability in aging mice (30.3 %). This study provides theoretical support for the view that fermentation is an effective means of developing functional foods.