Novel anticancer agents, kayeassamins C−I from the flower of Kayea assamica of Myanmar Original Research Article

A CHCl3-soluble fraction of 70% EtOH extract of the flower of Kayea assamica from Myanmar exhibited 100% preferential cytotoxicity (PC100) against human pancreatic cancer PANC-1 cells under nutrient-deprived conditions at 1 μg/mL. Bioassay-guided fractionation and isolation afforded nine new coumarins, kayeassamins A (8), B (9), and C−I (1−7), together with nine known coumarins (10−18). The structures of these compounds were identified by extensive spectroscopic techniques as well as by comparison with published data. Absolute configuration at C-1′ of 1 was established as S-configuration by the modified Mosher method. All the isolates were evaluated for their in vitro preferential cytotoxicity using novel anti-austerity strategy. Among them, the novel coumarins, kayeassamins A (8), B (9), D (2), E (3), and G (5) exhibited the most potent preferential cytotoxicity (PC100 1 μM) in a concentration- and time- dependent manner and induced apoptosis-like morphological changes of PANC-1 cells within 24 h of treatment. Based on the observed cytotoxicity, structure-activity relationships have been established.