(631t) Evaluation of the Biopharmaceutical Potential of the Lichen Isolate Xanthoparmelia Somloensis

The Black Hills of South Dakota offer a biodiversity in lichen species with a great potential for biopharmaceutical applications. The present study was carried out to evaluate the antibacterial and antioxidant activities of the lichen isolate Xanthoparmelia somloensis, native to the Black Hills. The antibacterial activity was assayed against four clinical strains using an agar well diffusion method. Except for Escherichia coli, the antibacterial and antioxidant extracts were found inhibitory to Streptomyces aureus, Streptococcus pyogenes and Steptococcus agalactiae with minimum inhibitory concentration values in the range 0.7-0.9 mg/ml. The antioxidant activity of the lichen extracts was assessed using the 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging assay. The lipid peroxidation reaction of acetone and methanol extracts was inhibited 85% and 81%, respectively A free radical scavenging activity of 77% (acetone extract) and 65% (methanol extract) was determined. It was demonstrated that both the antibacterial and antioxidant activities correlated well with the protein to polysaccharide ratio rather than the polyphenol content of the lichen extracts. The results reported here warrant further investigations to establish the usefulness of X. somloensis in biomedical applications such as treatment of respiratory and urinary tract infections.