Cytotoxicity evaluation and isolation of a chroman derivative from Phyllanthus amarus aerial part extract

Chemical and cytotoxicity examinations of the crude methanol extract of the aerial parts of Phyllanthus amarus Schum. et Thonn. (Euphorbiaceae) were investigated. The cytotoxicity property of the P. amarus was evaluated in vitro, using the human ovarian A2780 cancer cell. Bioassay-guided fraction of the crude extract (IC50 value of 31.2 mu g/mL) showed that the dichloromethane fraction was most toxic with an IC50 value of 22.7 mu g/mL, whereas the polar methanol fraction was least cytotoxic with an IC50 value of 31.2 mu g/mL. This led to the isolation of a new chroman derivative from the dichloromethane fraction. On the basis of nuclear magnetic resonance and mass spectral data, the structure of the chroman was established as 4,4,8-trimethoxy chroman. The compound exhibited very little or no in vitro cytotoxicity with an IC50 of 16.2 mu g/mL, relative to actinomycin, the reference compound, with an IC50 of 2.0 ng/mL. It can therefore be concluded that the aerial parts of P. amarus, an extensively used plant remedy in various African and Asian Pacific ethnomedicines, is relatively nontoxic.