(7R,8S) and (7S,8R) 8-5' Linked Neolignans from Egyptian Herbal Medicine Anastatica hierochuntica and Inhibitory Activities of Lignans on Nitric Oxide Production

Abstract

Three new (7R,8S) and (7S,8R) 8-5' linked neolignans named hierochins A (1), B (2), and C (3) were isolated from an Egyptian herbal medicine, the whole plants of Anastatica hierochuntica.The absolute stereostructures of new compounds were elucidated on the basis of chemical and physicochemical evidence.Both enantiomers, (7R,8S) and (7S,8R)-type neolignans, were found to coexist in a state of a little differing functional structure.The effects of isolated lignans on nitric oxide production in lipopolysaccharide-activated macrophages were examined and three known neolignan constituents were found to show inhibitory effects on nitric oxide production and induction of inducible nitric oxide synthase.The Cruciferae plant, Anastatica hierochuntica, is widely distributed in the Sahara-Arabian desert areas and the whole plants of A. hierochuntica are prescribed for the treatment of fatigue and uterine haemorrhage in Egyptian folk medicine and are used by women as a charm for child birth. 1,2During the course of our studies on bioactive constituents of Egyptian herbal medicines, [3][4][5][6] we reported the structure elucidation of then new skeletal benzofuranoflavanones, anastains A and B, with hepatoprotective activities from this herbal medicine. 7As a continuation of the characterization studies on this natural medicine, we additionally isolated optically pure (7R,8S) and (7S,8R) 8-5' linked neolignans including three new neolignans termed hierochins A (1), B (2), and C (3) from the whole plants of A. hierochuntica.In addition, we examined the inhibitory effect of isolated lignans from the whole plants of A. hierochuntica on nitric oxide (NO) production in lipopolysaccharide