Associations of Bioactive Constituents of <i>Aster yomena</i> with Environmental Variables

Aster yomena (Kitam.) Honda, a perennial herb belonging to the family Asteraceae, is widely used in traditional Japanese cuisine and folk medicine. However, the bioactive constituents of A. yomena have not been sufficiently characterized, limiting its practical applications. In this study, the phytochemicals and bioactivities of A. yomena and related Aster species collected from multiple locations across Kyushu, Japan were analyzed. Total phenolic, flavonoid, and saponin contents, antioxidant capacity, and antiproliferative activity against gastric cancer cells (AGS) were evaluated. Among the different plant parts, the leaves of A. yomena exhibited the highest phytochemical content and bioactivity. Regional comparisons revealed that leaf samples from coastal regions showed significantly higher flavonoid and saponin accumulation, as well as stronger antioxidant and antiproliferative activities, than those from inland populations. HPLC and LC/MS analyses identified chlorogenic acid, rutin, isoquercetin, nicotiflorin, and triterpenoid saponins as the major bioactive constituents. Regression analyses demonstrated that available phosphorus, exchangeable magnesium, and certain climatic factors (e.g., temperature range) were positively correlated with metabolite levels and bioactivities. These findings are expected to provide essential foundational data for future applications of the bioactive constituents of A. yomena in functional foods and pharmaceuticals.