Selective reactivity of 2-mercaptoethanol with 5beta,6beta-epoxide in steroids from Withania somnifera.
2-Mercaptoethanol reacts selectively with the 5beta,6beta-epoxy steroids isolated from Withania somnifera substituting the epoxide by a six-membered oxyethylene-2'-thio ring whereas it failed to show such reactivity on 6alpha,7alpha-epoxy withasteroids. The structure of the product has been elucidated by spectroscopic methods, especially applying extensive 2D NMR methods. The anticancer activity of withaferin A was lost in the reaction product indicating that its activity is also linked to the free 5beta,6beta-epoxide functional group.
Central Institute of Medicinal and Aromatic Plants, PO CIMAP, Lucknow, India. laxmisra@hotmail.com
Laxminarain
L
Misra
Payare
P
Lal
Narayan D
ND
Chaurasia
Rajender S
RS
Sangwan
Sudhir
S
Sinha
Rakesh
R
Tuli
D004852:Epoxy Compounds / Q000737:chemistry*; D004875:Ergosterol / Q000031:analogs & derivatives / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008515:Medicine, Ayurvedic; D008623:Mercaptoethanol / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry; D013256:Steroids / Q000737:chemistry; D032341:Withania / Q000737:chemistry*; D054358:Withanolides
D004852:Epoxy Compounds; D013256:Steroids; D054358:Withanolides; D008623:Mercaptoethanol; C009684:withaferin A; D004875:Ergosterol