Temporal dynamics of bioactive compounds in sweet tea (Lithocarpus litseifolius (Hance) Chun): Linking harvest stages to flavor and health benefits.

Sweet tea, the leaves of Lithocarpus litseifolius (Hance) Chun, received widespread attention for its edible and healthy values. This study employed non-targeted (UPLC-Q-Orbitrap-MS/MS) and quantitative (UPLC-QqQ-MS/MS) analyses to investigate the influence of harvest timing and geographic origin on its metabolite profile, flavor, and bioactivity. Among 505 identified metabolites, flavonoids and dihydrochalcones exhibited significant variation across developmental stages and regions. Electronic tongue analysis revealed that young leaves harvested in March, containing over 23 % trilobatin, displayed the highest sweetness and antioxidant activity, making them ideal for use as natural sweeteners. In contrast, mature leaves harvested in June, with over 13 % phlorizin, showed the strongest α-glucosidase inhibitory activity, suitable for developing functional foods aimed at reducing postprandial blood glucose. Statistical analysis confirmed strong correlations between trilobatin and sweetness (P < 0.01) and between phlorizin and α-glucosidase inhibition (P < 0.01). These findings highlight the critical role of harvest timing and regional factors in optimizing the quality of sweet tea for specific food and health applications, providing a scientific foundation for its standardized cultivation and utilization.