Cytotoxic constituents from Domohinea perrieri and Adenia gummifera

As part of our continuing search for novel anticancer agents from plants, an ethyl acetate extract of the stem bark of Domohinea perrieri Leandri (Euphorbiaceae) was found to exhibit cytotoxicity against several human cancer cell lines. Bioassay-guided fractionation of this extract, monitored by growth inhibition of the Lu1 (lung cancer) cell line, led to the isolation and characterization of six novel natural products, represented by four phenanthrene derivatives, one hexahydrophenanthrene derivative, and an alkyl glycoside. These compounds are 3,6-dihydroxy-1,7-dimethyl-9-methoxyphenanthrene (48), 3,6-dihydroxy-1-hydroxymethyl-9-methoxy-7-methylphenanthrene (50), 3,6-dihydroxy-7-hydroxymethyl-9-methoxy-1-methylphenanthrene (51), 3,6-dihydroxy-1,7-dihydroxymethyl-9-methoxyphenanthrene (54), domohinone (K062, 55), and ethyl-;The structure elucidation and identification of these compounds were carried out using spectroscopic techniques, including ;Adenia gummifera (Harv.) Harms (Passifloraceae) is a species that grows in various regions of Africa. Chloroform and hexane extracts of the leaves of this plant were found to possess significant cytotoxic activity when tested against a panel of human cancer cell lines. Bioassay-directed chromatographic fractionation of these active extracts using a human epidermoid carcinoma (KB) cell line assay, afforded three novel cytotoxic polyacetylenic compounds, namely, 1-acetoxy-6,7(E)-epoxy-2(E)-tetradecene-8,10,12-triyne-4...