Four new chemical constituents from the stems of Syringa oblata Lindl.

This study investigated the chemical constituents and biological activities of the stems of the Mongolian medicinal plant Syringa oblata Lindl. Through chromatographic separation and spectroscopic analysis, 30 compounds were isolated from the aqueous fraction, including four new and ten first-reported in Syringa species. Using human breast cancer MCF-7 cells as the research subject, the in vitro anti-tumor activity of the isolated compounds was evaluated by the CCK-8 method. In addition, among the 30 compounds detected by the DPPH method, nine showed strong antioxidant activity, with half maximal inhibitory concentration (IC₅₀) values lower than that of vitamin C. These results provide a scientific basis for the medicinal use of the stems of Syringa oblata Lindl.