The isolation, purification and complete characterization of the diterpene forskolin from nutritional supplements.

Forskolin (1) is a diterpene found in the Coleus forskohlii plant that has been examined for its medical properties resulting from adenylyl cyclase activation. This article describes a straightforward purification method of 1 from commercially available weight loss capsules. In addition, there has been some ambiguity with respect to the use of the name 'forskolin' to describe 1 and related diterpenes, which this report serves to eliminate. Herein we detail the complete spectroscopic characterization of purified 1 as well as its single crystal X-ray structure.