Oleanene glycosides of the aerial parts and seeds of Bupleurum falcatum and the aerial parts of Bupleurum rotundifolium, and their evaluation as anti-hepatitis agents

To facilitate effective resource utilization, we have investigated triterpene saponins such as saikosaponin from the aerial parts of Bupleurum (B.) falcatum L., which are commonly discarded. Seven oleanene saponins were isolated from this plant; they were classified as the 13,28-epoxy type, 12-ene type, 9(11),12-diene type, and 28-acid type on the basis of their structural characteristics. For comparison, we also examined the oleanene saponins of the seeds of B. falcatum and the aerial parts of B. rotundifolium L. to obtain seven saponins and one sapogenol from the former and thirteen oleanene saponins from the latter. Several compounds obtained from them were investigated for their hepatoprotective activity and hepatotoxicity. The 13,28-epoxy type saponins had hepatoprotectivity. Ursane type showed hepatotoxicity from middle concentration. The 11,13(18)-diene type saponins did not express hepatoprotective activity. The 28-acid type saponin which has a glucosyl carboxy group showed hepatoprotective action.