Protonophoric and uncoupling activity of royleanones from Salvia officinalis and euvimals from Eucalyptus viminalis.

The mechanism of action of quinones from the roots of Salvia officinalis L. (royleanones) and terpenoid phenolaldehydes from the leaves of Eucalyptus viminalis Labill. (euvimals) was studied. Royleanones and euvimals displayed marked protonophoric activity on artificial bilayer lipid membranes in vitro, and exerted an uncoupling action on oxidative phosphorylation in isolated rat liver mitochondria. The results suggest that biological membranes are the primary targets of royleanones and euvimals, and the protonophoric activity may contribute to the cytotoxicity and antimicrobial properties of these compounds. Copyright 2003 John Wiley & Sons, Ltd.