Bioassay-guided isolation of antimicrobial benzopyrans and phloroglucinol derivatives from Hypericum species.

Recently the crude methanol extracts of six Hypericum species were analysed against a panel of microorganisms and it was found that H. caprifoliatum Cham. & Schlecht., H. myrianthum Cham. & Schlecht. and H. polyanthemum Klotzsch ex Reichardt were the most active. This paper reports the activity of the hexane, chloroform and methanol fractions of these plants as well as the activity of some isolated compounds against Staphylococcus aureus determined by bioautographic procedures. (c) 2005 John Wiley & Sons, Ltd.