Evaluation of antifungal and cytotoxic activity of trans-Chalcone and α-Solanine

Abstract

Background: Dermatophytes are adapted to grow in keratinized tissues such as skin, nail and hair. Trichophyton rubrum is the most frequent cause of dermatophytosis in Brazil and in the world [1]. Despite its incidence there are only a limited number of antifungal drugs available for clinical use and some drugs are highly toxic to humans. In this regard, chalcones and alkaloids are phytochemical products which provide a rich source of chemical diversity for the development of new antifungals. Chalcones inhibit the biosynthesis of the cell wall and activity of fatty acid synthase in yeast [2,3]. The glycoalkaloid α-Solanine purified from potate sprout presents antifungal activity by altering cell membrane integrity and inhibition of sporulation [4]. The aim of the present study was to evaluate the minimum inhibitory concentration (MIC) and cytotoxicity (by MTT) of trans-Chalcone and α-Solanine toward strain MYA3108 of T.rubrum and the keratinocyte cell line HaCat, in order to evaluate the potential use of these phytochemicals against fungal skin infection. Materials and methods: The antifungal activity of the compounds was determinated by using the M38-A microdilution technique according to the Clinical and Laboratory Standards Institute [5] toward strain T.rubrum for 7 days at 28°C. Keratinocytes were cultures in RPPMI supplemented with 10% fetal calf serum and incubated at 37°C and 5% CO2. Cells were plated (2.5x105 cells/mL) in a 96-well tray 24 h prior to the beginning of the experiment. After addition of several concentrations of natural compounds or the vehicle, cells were analyzed after a period of 24 h using the MTT assay. Results: The MICs of α-Solanine and trans-Chalcone were 7.8 μg/mL, showing effectiveness against T. rubrum, while the inhibition of the HaCat cell line by trans-Chalcone (7.8 μg/ml) and α-Solanine (50 μg/ml) were 45.78% and 68.86% respectively. Conclusions: Finally, the α-Solanine is a potential candidate for the development of new antifungal drugs against T. rubrum, due to its significant antifungal activity and lower citotoxicity for human keratinocytes.