Thermal treatment enhances the resisting exercise fatigue effect of Phyllanthus emblica L.: Novel evidence from tannin conversion, metabolomics, and gut microbiota community analysis

Abstract Polyphenols are the main anti-fatigue component of Phyllanthus emblica (PE). However, polyphenols are so easy to transform that it is unknown that how drying and extraction methods driven by heating affect the anti-fatigue effect of PE. This manuscript investigated the effects of five drying methods on the chemical composition transformation and anti-fatigue of PE, and discussed the action mechanism. The results suggested that the anti-fatigue effect of PE with hot-air-dried at 100 ℃ was the best, which was as 1.63 times as that with freeze-drying. Ellagic acid (EA) may be a key component of PE in anti-fatigue, and its mechanism of action may be related to regulating intestinal microbiota, promoting the conversion of EA to urolithin A in vivo, protecting mitochondria, and regulating energy metabolism. This study first revealed the thermal transformation of polyphenols in PE, found the most effective strategy for enhancing the anti-fatigue function, and explores its action mechanism.