شناسايى و بررسى فعاليت ضد باكتريايى پنج گلسنگ بومى جمع آورى شده از حومه شهرمشهد در شرايط in vitro

In vitro antibacterial activity of five native lichens gathered from Mashhad suburbs

Lichens have been traditionally used for medical purposes in the pasts. Identification of lichens and study of their antibiotic effects seems to be essential. In this study, five types of lichens were collected from Mashhad suburbs and were identified from macroscopic and microscopic properties and biochemical experiments points of view. Methanol and acetone extracts of them were prepared by percolation and then 2mg/disc of every extracts were prepared. Then, their antibacterial activities were tested using Disc Diffusion Method (DDM) on Bacillus cereus, Bacillus subtilis, Seratia marces-ence, Staphylococcus aureus and Escherichia coli. Psora desipiens and Xanthoria el-egans had no activity against tested bacteria by 2mg/disc of extracts. The growth of tested gram positive bacteria was inhibited by extracts of Rhizoplaca chrysoleuca and R. melanophthalma, but in this concentration, these lichens had no effects on tested gram negative bacteria. Methanol extract of lichens preserved their antibacterial effects in 100°C for 30 minutes. L. muralis had the maximum antibacterial effect and its MIC (Minimum inhibition of concentration) was 100, 200, and 750Mg/ml against B. cereus, B. subtilis and S. aureus, respectively.