Ethnoveterinary medicine in the search for antimicrobial agents: antifungal activity of some species of Pterocaulon (Asteraceae).

Based on informal interview, ethnoveterinary information about plants used in the treatment of skin diseases were obtained. Plants from the genus Pterocaulon (Asteraceae) known as "quitoco" are used to treat problems popularly diagnosed as "mycoses", which can have both fungic and bacterial etiology. In order to validate this traditional practice, the crude methanolic extracts and fractions from the aerial parts of three species of Pterocaulon (Pterocaulon alopecuroides (Lam.) D.C., Pterocaulon balansae Chodat. and Pterocaulon polystachyum D.C.) grown in southern Brazil were analyzed for the in vitro antifungal activity against a panel of standardized and clinical opportunistic pathogenic yeasts and filamentous fungi including dermatophytes by the agar dilution method. The crude methanolic extract of Pterocaulon alopecuroides was the most active followed by the extract of Pterocaulon polystachyum. Pterocaulon balansae crude methanolic extract was the less active but its lipophilic fractions showed remarkable activity mainly against the dermatophytes.