Evaluating the antibacterial, hemolytic and cytotoxic activities of the Iranian Rana ridibunda skin extract as a new source of antimicrobial compound

Amphibian skins possess various antibacterial compounds that are effective against some microbial pathogens and are mostly released in response to environmental stress. In fact, the skin of Rana ridibunda, a large green frog, is a rich source of antimicrobial compounds that can be developed for therapeutic use. In the present study, the skin extract of Iranian Rana ridibunda was evaluated for its antimicrobial, hemolytic and cytototoxic activities. The frog specimens were collected from Minoodasht located in Golesten province in Iran, during 2009. Subsequently, their skins were removed and the intended compounds were extracted. The crude extract was partially purified by gel filtration chromatography. The antimicrobial effects of skin extract were assessed against various microorganisms such as Escherchia coli, methicillin-resistant and -sensitive Staphyloccus aureus, vancomycin-resistant and -susceptible Enteroccus fecalis, Pseudomonas aeroginosa and Candida albicans. In addition, its minimum inhibition concentration, cytotoxic and hemolytic activities were determined. The crude extract of Rana ridibunda skin had valuable antimicrobial effects against methicillin-resistant and -susceptible S. aureus in comparison with E.coli and vancomycin-resistant and -susceptible E. fecalis. Besides, no antimicrobial activities were seen against P. aeroginosa or C. albicans. Moreover, the hemolytic and cytotoxic activities of the skin extract were minimal. The antimicrobial activity of Iranian Rana ridibunda was comparable to those isolated from other Rana species. In conclusion, the skin extract of Rana ridibunda had the potential for a new therapeutic agent against the emerging drug-resistant bacteria, particularly methicillin-resistant and -sensitive S. aureus.