摘要：Antimicrobial activity of the acetone, methanol and ethanol extracts of some common lichen species such as Usnea longissima Ach., Everniastrum cirrhatum (Fr.) Hale, Peltigera polydactylon (Neck.) Hoffm. and Sulcaria sulcata (Lév.) Bystr. ex Brodo & D. Hawksw., were screened in vitro against six clinically important pathogenic bacteria, Staphylococcus aureus, Streptococcus faecalis, Bacillus cereus, Pseudomonas aeruginosa, Salmonella typhimurium and Escherichia coli by Kirby-Bauer technique of disc diffusion method. Minimum inhibitory concentration was taken out by Broth micro dilution method according to the NCCLS guidelines. Acetone, methanol and ethanol extracts of the investigated lichens showed relatively strong antimicrobial activity against all the gram positive bacteria and two gram negative bacteria.It was found that the inhibition zone of tested bacteria against lichen extracts varied between 7.6 – 30.7 mm diameters. The lowest MIC value was observed to be as low as 6.25 µg/ml against B. cereus of U. longissima. Generally the lichen extracts tested demonstrated antimicrobial effect which suggests a possibility of their use in treatment of various diseases caused by these and similar microorganisms.
关键词：Kirby-Bauer method – Lichenized fungi – MIC – pathogenic bacteria
