RESUMO
BACKGROUND/AIM: Aurelianolide A and B were identified and isolated from Aureliana fasciculata var. fasciculata leaves. Withanolides are naturally occurring C-28 steroidal lactone triterpenoids with cytotoxic and anticancer properties, among other relevant pharmacological activities. Herein we have described, for the first time, the cytotoxic effects of aurelianolides on human cancer cells. MATERIALS AND METHODS: Aurelianolide A and B were tested on human leukemia cell lines: THP-1, MOLT-4, Jurkat, K562 and K562-Lucena 1. RESULTS: For aurelianolide A, MOLT-4 had the lower IC50 (1.17 µM) and for aurelianolide B, Jurkat was the most susceptible cell line (IC50 2.25 µM). On the other hand, the multidrug resistant (MDR) cell line K562-Lucena 1 showed higher IC50 for both aurelianolides. Using 293T, a non-tumor embryonic kidney cell line, we observed an excellent selectivity index for both aurelianolides, from 2.24 (aurelianolide B in K562-Lucena 1) to 45.5 (aurelianolide A in MOLT-4). Aurelianolide A and B activated caspase 3/7 with consequent induction of apoptosis on Jurkat and K562-Lucena 1 cell lines. We have not observed induction of necrosis. CONCLUSION: Aurelianolides A and B have important cytotoxic effects on human leukemia cell lines by the activation of the caspase pathway.