Two new phenylpropanoids, named stytonkinol A (1) and stytonkinol B (2), have been isolated from the resin of Styrax tonkinensis (Pierre) Craib ex Hartw. Their structures were determined by spectroscopic analysis, including 1D and 2D NMR, and HR-ESI-MS. Two isolated compounds were assayed for cytotoxic activities against five tumor cell lines (HepG-2, A549, Hela, MCF-7, and PC-3) by Cell Counting Kit-8 (CCK-8) test in vitro. The cytotoxic effectiveness observed against Hela, and MCF-7 cell lines of compound 1 were superior or similar to the positive control cisplatin (IC50 values of 40.95 and 47.36 μM), with IC50 values of 26.75 and 45.16 μM, respectively, while it showed moderate cytotoxic activities against the HepG-2 and PC-3 cell lines. Compound 2 showed moderate cytotoxic activities on cells MCF-7 with IC50 values of 57.1 μM.
Keywords: Cytotoxic activities; Phenylpropanoids; Resin; Styrax tonkinensis.