Protection Impacts of Coix lachryma-jobi L. Seed Lactobacillus reuteri Fermentation Broth on Hydrogen Peroxide-Induced Oxidative Stress in Human Skin Fibroblasts

This study researches the active ingredients in the fermented and aqueous extracts of three types of Coix seed. The results show that the active contents of total sugars, total phenols and total proteins of Coix seed fermented with Lactobacillus reuteri, Saccharomyces cerevisiae and Lactobacillus bulgaricus are significantly higher compared to unfermented Coix seed aqueous extract (CW), and the free radical scavenging ability of Coix seed Lactobacillus reuteri fermented extract (CLRF) is significant. The protective effects of CLRF on hydrogen peroxide (H2O2)-induced oxidative stress in human skin fibroblasts (HSF) are investigated. The results show that cell viability, total antioxidant capacity, superoxide dismutase (SOD) activity, catalase (CAT) activity, collagen type I (COL-I) content and synthesis of hyaluronic acid (HA) significantly increased, and reactive oxygen species (ROS), matrix metalloproteinase-1 (MMP-1) content are decreased in CLRF-treated HSF compared to CW and damage model groups, providing effective protection to skin structure. The results show that CLRF can stimulate the PI3K/AKT signaling pathway, inhibiting intracellular ROS levels, positively regulating COL-I genes and significantly reducing MMP-1 expression, with anti-oxidative damage effects. As such, this study provides a theoretical basis for applying CLRF as a novel anti-oxidative agent in the cosmetics industry.