Study on the differences of metabolites and their bioactivities of Lithocarpus under different processing methods

Lithocarpus litseifolius (Hance) Chun is a plant with great exploitation value rich in trilobatin and phlorizin with hypoglycemic effects, but its processing and storage methods have not been developed. In this study, it was processed by exploring three processing methods, sun-dried Lithocarpus tea (SLT), non-fermented green Lithocarpus tea (GLT), and fermented black Lithocarpus tea (BLT), to analysis of volatile substance differences using GC-MS, chemical composition differences by non-targeted metabolomics using LC-MS and evaluate of biological activity by antioxidant and α-amylase and α-glucosidase inhibition activities. The results showed that GLT had the highest phenolic, flavonoid, trilobatin and phlorizin content; BLT had decreased catechin-like substances and improved sensory quality. In addition, the metabolic pathway analysis by comparing the differential metabolites showed that the secondary metabolite metabolic pathway, amino acid metabolism and ABC transport pathway were the main differential enrichment metabolic pathways. Both GLT and BLT have good hypoglycemic ability. The specific compounds and biochemical properties exhibited by Lithocarpus under different processing methods can provide a reference for its development of healthful teas.