Sterols of some Clerodendrum species (Verbenaceae): occurrence of the 24 alpha- and 24 beta-epimers of 24-ethylsterols lacking a delta 25-bond.
The configurations at C-24 of 24-alkylsterols of six samples of Clerodendrum species (Verbenaceae) - the aerial parts of C. fragrans, C. inerme, C. infortunatum, C. scandens, and C. siphonanthus, and the seeds of C. infortunatum - were examined by NMR. All samples contained 24 beta-ethylsterols possessing a delta 25-bond, clerosterol and 22-dehydroclerosterol, as the dominant sterol components. The other 24-ethylsterols lacking a delta 25-bond, 24-ethyl-22-dehydrocholestanol, 24-ethylcholesterol, and 24-ethyl-22-dehydrocholesterol, which were present as minor components, were shown to be mixtures of the 24 alpha- and 24 beta-epimers, with the 24 alpha-epimers predominating in all cases. Four minor 24-methyl-sterols, 24-methylcholestanol, 24-methylcholesterol, 24-methyl-22-dehydrocholesterol, and 24-methyllathosterol, were shown to be C-24 epimeric mixtures, whereas two others, 24-methyl-22,25-bisdehydrocholesterol and 24-methyl-22-dehydrolathosterol, were found to be present only as the 24 beta-epimers. This is the first report of the occurrence of 24 beta-ethyl-22-dehydrocholestanol in higher plants.
Akihisa
T
T
College of Science and Technology, Nihon University, Tokyo.
Matsubara
Y
Y
Ghosh
P
P
Thakur
S
S
Tamura
T
T
Matsumoto
T
T
D055598:Chemical Phenomena; D002621:Chemistry; D002775:Cholestadienols / Q000032:analysis; D002784:Cholesterol / Q000031:analogs & derivatives / Q000032:analysis; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D009682:Magnetic Resonance Spectroscopy; D010944:Plants / Q000032:analysis*; D012639:Seeds / Q000032:analysis; D012855:Sitosterols / Q000032:analysis; D013261:Sterols / Q000032:analysis*; D013265:Stigmasterol / Q000031:analogs & derivatives / Q000032:analysis
D002775:Cholestadienols; D012855:Sitosterols; D013261:Sterols; D002784:Cholesterol; D013265:Stigmasterol