[Isolation and analysis of a new phytoecdysteroid from Cyanotis arachnoidea C. B. Clarke].

Cyanotis arachnoidea is a plant with plenty of phytoecdysteroid. To study the active compound in it, a new phytoecdysteroid with 5alpha-cholesta skeleton, was isolated from the whole plant of Cyanotis arachnoidea C. B. Clarke by using various chromatographic methods (alumina column chromatography, silica gel column chromatography, octadecyl silane (ODS) column chromatography, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC)). Its structure was analyzed on the basis of 1D and 2D nuclear magnetic resonances (NMR), electrospray ionization mass spectrometry (ESI-MS) methods. It is a compound with structure of 3beta,14alpha, 14alpha,20R,22R,25-hexahydroxy-5alpha-cholest-7-en-6-one, which is a rare phytoecdysteroid with 5alpha-H.