Antitumor agents, 138. Rotenoids and isoflavones as cytotoxic constitutents from Amorpha fruticosa.

Eight cytotoxic compounds have been isolated from the CHCl3 extract of Amorpha fruticosa. One compound, 6'-O-D-beta-glucopyranosyldalpanol [10], is a new cytotoxic rotenoid. Another known rotenoid, 12 alpha beta-hydroxyamorphigenin [6], was first shown to exhibit extremely potent cytotoxicity (ED50 < 0.001 microgram/ml) in six neoplastic cell lines. In addition to these compounds, three isoflavones (afrormosin [1], 7,2',4', 5'-tetramethoxyisoflavone [2], 8-methylretusin [3]) and five rotenoids (amorphispironone [4], amorphigenin [5], dalpanol [7], 12a beta-hydroxydalpanol [8], and tephrosin [9]) were isolated. Compound 8 was isolated for the first time as a natural product from this plant. The structures of these compounds were established on the basis of spectral data; some were further confirmed by X-ray crystallographic analysis.