Luteolin derivatives and antimicrobial activity of Achillea tenuifolia Lam. methanol extract

Abstract

Flavonoids are a large class of polyphenols, with more than 4000 combinations and have some very important medicinal and biological activity, especially antiradical, antioxidant, and to prevent cancer effects. In this study, two luteolin derivatives have been isolated from the aerial parts of Achillea tenuifolia and purified by column chromatography, TLC, and preparative TLC techniques to yield compounds. The chemical structures were determined by 1H NMR, 13C NMR, HMBC and IR spectroscopy techniques and were established as 5-hydroxy-3′,4′-dimethoxyflavone-7-O-(rhamnoside) (1) and 5-hydroxy-3′-methoxyflavone-4′-O-(penthenyl-4-one)-7-O-(2″-(rhamnosyl) rhamnoside) (2). The structure of the compounds was determined by spectroscopic techniques and by comparison with published data. The antimicrobial activity of the methanol extract was tested against three different bacteria by disc diffusion method and showed maximum inhibitory activity against Gram-positive bacteria, especially Bacillus subtilis.