• Natural Product Sciences
• /
• v.3 no.1
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• pp.14-18
• /
• 1997

Two new diterpenoids, orientalin A (1), and B (2), have been isolated together with six known compounds, kirenol (3), $ent-16{\beta},17-dihydroxykauran-19-oic$ acid (4), $ent-16{\beta},17-dihydroxykauran-19-oic$ $acid-16{\beta},l7-acetonide$ (5), $3,7-dimethylquercetin$ (6), ${\beta}-sitosterol$ (7), and daucosterol (8) from the ethanol extract of Siegesbeckia orientalis (Compositae). Their chemical structures have been elucidated as $ent-15-acetoxy-2{\alpha},16,19-trihydroxypimar-8(14)-ene$ (1), $ent-16-acetoxy-2{\alpha},15,19-trihydroxypimar-8(14)-ene$ (2), respectively, on the basis of chemical and spectral evidence.