Antimicrobial, Antinociceptive and Anti-inflammatory Activity Studies on Pseudevernia furfuracea

Abstract

Lichens are a large group of organisms which are represented by approximately 18 000 species worldwide. Lichens form an interesting group of lower plants featuring algae and fungi symbiotically combined. Aliphatic, cycloaliphatic, aromatic and terpenic compounds were reported as their secondary metabolites. Lichens and their metabolits have some biological activities such as antimicrobial, antitumor, antioxidant, anti-inflammatory, analgesic and antipyretic, enzyme inhibiting and cytotoxic. Pseudevernia furfuracea (L.) Zopf (Parmeliaceae) is a common epiphytic lichen in the conifer-hardwood forest of Anatolia. This lichen is used in traditional medicine as a treatment for wound, eczema and hemorrhoids in Turkey. In the present study, methanolic extract from thallus of P. furfuracea and its fractions were investigated for its in vitro antimicrobial, and in vivo anti-inflammatory and antinociceptive activities. Significant antimicrobial activities were observed against Gram (+) microorganisms and Candida krusei. For the anti-inflammatory activity assessment, carrageenan-induced hind paw edema, 12-O-tetradecanoyl-13-acetate (TPA)-induced mouse ear edema and for the antinociceptive activity, p-benzoquinone-induced abdominal constriction tests were used. Methanolic extract of the plant was found to possess significant inhibitory activity on the carrageenan-induced hind paw edema model in mice whereas the other fractions did not show any activity. While CH2Cl2 and EtOAc fractions showed notable anti-inflammatory activity on carrageenan-induced hind paw edema model without inducing any apparent acute toxicity or gastric damage, these fractions did not show against 12-O-tetradecanoyl-13-acetate (TPA)-induced mouse ear edema model and antinociceptive activity. 2,4-dihydroxy-3,6-dimethyl-benzoic acid methyl ester (=atraric acid) [1], methyl hematommate [2], and methyl chlorohematommate [3] were isolated from the active fractions as the main compounds. The structures of 1–3 were elucidated by spectroscopical (NMR, MS) means.