Structure of a novel phytoecdysteroid, vitexirone, and efficient isolation of phytoecdysteroids fromVitex fisherii.

A novel phytoecdysteroid, vitexirone, has been isolated from a MeOH extract of the root bark of the East African medicinal plantVitex fisherii by recycling high-performance liquid chromatography on a semipreparative scale. In addition, three known phytoecdysteroids, 20-hydroxyecdysone, ajugasterone C, and turkesterone, also were isolated. The structure of vitexirone has been established spectroscopically. The position and stereochemistry of the 11-α-hydroxy group of ajugasterone C and vitexirone were confirmed by the(1)H-(1)H homonuclear COSY NMR data. These phytoecdysteroids disrupt the molting process of the pink bollwormPectinophora gossypiella.