Enhancing the Anti-Aging Potential of Green Tea Extracts Through Liquid-State Fermentation with Aspergillus niger RAF106.

Microbial fermentation diversely modulates the bioactivity of green tea extracts (GTE), but its effects on anti-aging potential remain under-explored. This study investigated the effects of liquid-state fermentation by Aspergillus niger RAF106 on the anti-aging properties of GTE from Biluochun and identified its longevity-promoting metabolites. The unfermented GTE used herein showed no or limited effects, but the four-day fermented tea extracts (GTE-A4) significantly extended the mean lifespan in Caenorhabditis elegans, enhanced motility and stress resistance, and improved mitochondrial function and antioxidant properties, while reducing lipid accumulation and oxidative damage. The pro-longevity effect depended on insulin/IGF-1, MAPK, and p53 pathways and required transcription factors DAF-16 and HSF-1. Fermentation periods shorter or longer than 4 days led to reduced efficacy. Fermentation with RAF106 dynamically altered chemical composition and induced the enrichment of various longevity-promoting metabolites in GTE-A4, including proanthocyanidin A2, aromadendrin, and dalbergioidin-all newly identified as anti-aging agents. These findings demonstrate that RAF106 fermentation improves the anti-aging potential of green tea and provides a scientific basis for using precision fermentation to develop advanced anti-aging functional ingredients from tea extracts.