Antimicrobial effect of white sage (Sphacele salviae (lindl.) briq.) leaf extract on gram-positive and gram-negative bacteria

Abstract

White sage, a Chilean endemic medicinal herb, has a similar chemical composition similar to other Labiatae species, which have reported inhibitory effects on Gram-positive and Gram negative bacteria. In order to identify inhibitory and/or lethal effect of white sage leaf extract on two Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), an in vitro laboratory test was performed. Leaves were collected from wild populations located in Los Vilos, Coquimbo Region, and Cuesta El Melón, Valparaíso Region, Chile. The extract was obtained by steam stripping with dichloromethane. The biological activity of the extract was determined by agar susceptibility diffusion tests, using three concentrations (120, 200 y 300 mg mL^-1). The most sensitive microorganisms were Gram-positive bacteria, most inhibited at the concentration of 300 mg mL^-1, but inhibited from 120 mg mL^-1. Gram negative bacteria were only repressed at 300 mg mL^-1. There is a possibility that the inclusion of a White sage extract could be feasible to counteract the permanent and progressive appereance of multi-resistant bacteria.