Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, and Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, PR China. Electronic address: [Email]
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 IC50 values from 5.41 to 15.43 μM. This is the first study for C. brachythyrsa.