Antimicrobial Activity and Chemical Composition of Pilosella sandrasica, an Endemic Species to Turkey

Abstract

The antimicrobial activity of the n-hexane, chloroform, ethyl acetate and ethyl alcohol extracts of the aerial parts of P. sandrasica, endemic to Turkey collected from Mugla area, was evaluated against microorganisms including multi-antibiotic resistant bacteria. These activities were determined using the disc diffusion method, with 25 mu l of each extract containing 25 mg/ml crude extract per disc. For this study, 3 Gram-negative standart test bacteria (Enterobacter aerogenes RSKK 720, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922), 4 Gram-positive standart test bacteria (Micrococcus luteus NRRL B-4375, Bacillus subtilis ATCC 6633, Streptococcus mutans CNCTC 8/77 and Staphylococcus aureus ATCC 25923), 2 yeasts (Candida albicans ATCC 10239 and Candida tropicalis RSKK 665) and multi-antibiotic resistant strains of Stenotrophomonas maltophilia and various species of Staphylococcus were used. The chemical composition of the chloroform extract of this plant was determined by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Its ethyl alcohol extract produced 10-17 mm inhibition zones for Gram-negative bacteria, 11-21 mm inhibition zones for Gram-positive bacteria. The hexane and ethyl acetate extracts had no effect on microorganisms tested. The chloroform extract inhibited the growth of E. aerogenes, P. aeruginosa and E. coli. All the extracts had no effect on yeasts. But the ethyl alcohol extract showed anticandidal activity on C. tropicalis. Total 11 compounds were determined in the chloroform extract. The major compounds of the chloroform extract of the plant were carvacrol (24.8%), caryophyllene oxide (22.5%), cedrane-8,13-diol (15.5%), hexahydro farnesylacetone (11.3%), aromadendrene epoxide (8.3%), respectively.