Identification, anti-Alzheimer's disease and antiaging activities of cinnamoylated flavoalkaloids from green tea

Tea catechins are important functional and taste ingredients. The limit content of new tea catechins restricts their identification and utilization. This study proposed a new strategy including construction of tea component transformation networks (TCTN), speculation of new molecules by LC-ESI-HRMS/MS detection, and synthetic verification to address this problem. The new precursor ion 546.1749 [M-H]- detected in Yingde green tea proposed the presence of a new cinnamoylated flavoalkaloid possibly derived from theanine, p-hydroxycinnamic acid, and epicatechin through nucleophilic reaction. We thus synthesized the molecule and purified three isomers (1–3) with the same molecular weight at 547. Compounds 1–3 are widely present in 18 different cultivars of green tea by targeted LC-ESI-HRMS/MS detection. Meanwhile, 1 and 2 (50 μM) showed anti-Alzheimer's disease (anti-AD) potentials using the transgenic CL4176 strain of Caenorhabditis elegans (C. elegans). Notably, 2 (200 μM) strikingly prolonged the lifespan of wild type C. elegans by 66%. This study demonstrates that the TCTN strategy can guide us to find new molecules from tea and the potential anti-AD and antiaging values of cinnamoylated flavoalkaloids.