Antitumor agents, 82. Cytotoxic sapogenols from Aesculus hippocastanum

Two cytotoxic sapogenols, the new hippocaesculin (1) and the known barringtogenol-C 21-angelate (2), were isolated from the acid hydrolysis product of a crude saponin fraction that was obtained from the fruits of Aesculus hippocastanum. The structures of 1 and 2 were determined from their chemical transformations and spectral data. Compound 1 is either 21-O-angeloyl, 22-O-tigloyl R1-barrigenol, or 21-O-tigloyl, 22-O-angeloyl R1-barrigenol.