Polyphenolic constituents of the methanolic extract of Callistemon viridiflorous leaves and its antimicrobial activity

Introduction: The genus Callistemon (family: Myrtaceae) contains 34 species which are widely distributed in the temperate regions and used in folk medicine. Methods: Chromatographic separation of 80% MeOH extract of the leaves of Callistemon viridiflorus (sims) Sweet (Cv) was performed. Results: Seven known polyphenolic compounds were isolated for the first time from this species: gallic acid, ellagic acid, isoquercetin, hyperin, 1,2:3,4-(bis(s)-hexahydroxy diphenoyl-β-D-glucopyranose, nilocitin and quercetin-3-O-α-L-glucuronopyranoside. The methanolic extract of Cv leaves exhibited a significant anti-microbial activity against the tested microorganisms.