Antiplasmodial and cytotoxic activity of phloroglucinol derivatives from Hypericum erectum Thunb.

The chloroform extracts of whole plants of Hypericum erectum were investigated for antiplasmodial activity against chloroquine-sensitive strains of Plasmodium falciparum. Five phloroglucinol derivatives, otogirin (1), otogirone (2), erectquione A (3), erectquione B (4), and erectquione C (5) were isolated from the whole plants of H. erectum. Also, five compounds were evaluated for in vitro antiplasmodial activities as well as their cytotoxic potential on SK-OV-3 cancer cell line cells. Compounds 2, 4 showed notable growth inhibitory activity against chloroquine-sensitive strains of Plasmodium falciparum with IC(50) values from 5.6 and 7.2 microM. This compound showed no significant cytotoxicity (IC(50) > 150 microM) evaluated using SK-OV-3 cancer cell line cells.