New isomalabaricane analogues from the sponge Rhabdastrella providentiae and their cytotoxic activities

Publication date: August 2018 Source:Phytochemistry Letters, Volume 26 Author(s): Phan Van Kiem, Duong Thi Dung, Pham Hai Yen, Nguyen Xuan Nhiem, Tran Hong Quang, Bui Huu Tai, Chau Van Minh Five new isomalabaricane analogues, named rhabdastrellins G - K (1–5), and three known compounds including jaspolide C (6), globostelletin C (7), and globostelletin D (8) were isolated from the sponge Rhabdastrella providentiae collected in the Eastern Sea of Vietnam. Their chemical structures were determined by HR-ESI-MS, NMR spectroscopy, experimental and calculated circular dichroism spectra. The isolated secondary metabolites were evaluated for their cytotoxicity toward HepG2, LU-1, MCF-7, HL-60, and SK-Mel2 human cancer cell lines. New isomalabaricane analogues 1-3 exhibited significant cytotoxicity with IC50 values ranging from 11.2 ± 1.4 to 84.8 ± 6.7 μM. Interestingly, the 20(22)Z stereoisomer (2) exhibited dramatic increase of cytotoxic activity in comparison with 20(22)E isomer (1). Graphical abstract
Source: Phytochemistry Letters - Category: Chemistry Source Type: research