Minor Constituents from Coleus forskohlii

Abstract

Two new labdanoids, forskolin E and F, with forskolin A, B, C and D, have been isolated from the chloroform extract of the whole plants of Coleus forskohlii . The chemical structures of the two minor constituents have been established as 1α,7β-diacetoxy-8,13 epoxy-6β-hydroxylabd-14-en-11-one(1) and 7β-acetoxy-8,13-epoxy-6β,9α-dihydroxylabd-14-en-11-one(2), respectively, on the basis of detailed spectroscopic analysis and all assignments were supported by 1H- 1H COSY, HMBC and HMQC spectrum (see table 1).