Abstract:
Urinary tract infections are the common infections in community and hospital settings and infect millions of people worldwide every year. The present study was undertaken to determine antibacterial efficacy of extracts of three Parmotrema species viz., P. tinctorum, P. grayanum and P. praesorediosum, macrolichens from Western Ghats of Karnataka, India. The powdered lichen materials were extracted using methanol in soxhlet assembly. Antibacterial activity of lichen extracts was determined against five clinical isolates viz., Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli of urinary tract infection by agar well diffusion assay. The lichen extracts showed dose dependent inhibition of test bacteria. Inhibitory efficacy was highest against Gram positive bacteria than Gram negative bacteria. Overall, high and least inhibitory activity was observed against E. faecalis and K. pneumoniae respectively. The MIC of extracts was found to be least for Gram positive bacteria (0.3 to 0.6mg/ml) than Gram negative bacteria (0.6 to 2.5mg/ml). Thin layer chromatogram revealed the presence of Lecanoric acid, Atranorin, Orsellinic acid, Protolichesterinic acid, Chloroatranorin, Protopraesorediosic acid and Praesorediosic acid in lichen materials. The antibacterial potential of lichen extracts could be ascribed to the presence of secondary metabolites. The Parmotrema species appears to be promising source of agents with inhibitory activity against antibiotic resistant urinary tract pathogens.

Keywords: Western Ghats, Parmotrema, Antibacterial Activity, Urinary Tract Infections.