Bioactivity guided phytochemical study of Clematis hirsuta growing in Saudi Arabia

Bioactivity guided phytochemical study of the petroleum ether and butanol extracts of Clematis hirsuta resulted in the isolation of 12 compounds. Rat paw edema as a model of acute inflammation was used to evaluate the anti-inflammatory activity of the extracts and the chromatographic fractions. Five known sterols and triterpenes namely: β-amyrin (1), lupeol (2), β-sitosterol (3), oleanolic acid (4) and stigmasterol glycoside (5) were isolated from the petroleum ether extract. The n-butanol extract afforded two compounds reported for the first time from natural source: (S)-(+)-dihydro-5- (hydroxymethyl)-2(3H)-furanone (7) and (S)-(-)-5-hydroxymethyl-2(5H)-furanone (8). In addition, anemonin (6), dinydro-4-hydroxy-5-(hydroxymethyl)-2(3H)- furanone (2-deoxy-D-ribono-1,4-lactone) (9), biophenol (cimidahurin) (10), glucose (11) and sucrose (12) were also identified. The structures were determined from spectroscopic data including 1D- and 2D-NMR experiments.