Cytotoxic and anticarcinogenic activity of the ent-kaurene diterpenoid, melissoidesin, from Isodon wightii (Bentham) H. Hara.

Isodon wightii is a common plant found in the Western Ghats of South India. The ent-kaurene diterpenoid melissoidesin, isolated from the leaves of I. wightii, showed significant cytotoxicity against lung cancer and neuroblastoma cell lines with IC(50) values of 6 and 4.2 microg mL(-1), respectively. The prevention of deoxyribose degradation activity of melissoidesin was significant and the IC(50) value was calculated to be 163.1 microg mL(-1). The anticarcinogenic activity of melissoidesin by comet assay showed significant DNA damage protecting activity in a dose-dependent manner.