Taibaijaponicains C and D: Two New Diterpenoids from Isodon japonica

Abstract

Two new C-20-oxygenated ent-kaurene diterpenoids, taibaijaponicains C and D, together with five known compounds, were isolated from the ethanol extract of the leaves and branches of Isodon japonica (Burm. f.) Hara. The structures of new compounds were elucidated as 1α-aectoxy-7β,12β,15α-trihydroxy-16α-hydroxymethyl-7,20-epoxy-ent-kaurane and 1α-acetoxy-2β,3α,6β,7β,12β-pentahydroxy-7,20;19,20-diepoxy-ent-kaur-16-en-15-one, respectively, on the basis of detailed spectroscopic analysis.

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