Cytotoxic arylalkenyl α,β-unsaturated δ-lactones from Cryptocarya brachythyrsa

Abstract Three new arylalkenyl α , β -unsaturated δ -lactones, cryptobrachytones A – C ( 1 – 3 ), together with one known analogue kurzilactone ( 4 ), were isolated from the leaves and twigs of Cryptocarya brachythyrsa . Their structures were elucidated based on extensive spectroscopic data and electronic circular dichroism (ECD) analysis. All the isolates were evaluated in vitro for anti-proliferative activity against a panel of five human cancer cell lines and one human normal cell, respectively, and the results showed 1 , 2 and 4 possessing significant selective cytotoxicity toward the human cancer cell lines with IC 50 values from 5.41 to 15.43 μM. This is the first study for C. brachythyrsa .