Antimycotic activity of some amino acids against dermatophytes

20 amino acids were assayed at 1% concentration for their toxicity against the mycelial growth of two dermatophytes viz., Microsporum gypseum and Trichophyton mentagrophytes. L-Cysteine hydrochloride exhibited absolute toxicity against both the test pathogens while DL-aspartic acid was found active against Microsporum gypseum only. The minimum inhibitory concentrations of L-cysteine hydrochloride was found to be 0.5 and 0.4% against M. gypseum and T. mentagrophytes, respectively, at which it showed mycostatic nature. However, the amino acid exhibited mycocidal activity at 0.9 and 0.8% against M. gypseum T. mentagrophytes, respectively. The spectrum of L-cysteine hydrochloride was studied at 1 and 0.5% concentrations against 24 human and animal pathogenic fungi and it was found to possess broad range of activity. The mycotoxicity of amino acid remained unaltered at high temperature, on autoclaving and against high inoculum density. Besides, it showed stronger activity in comparison to four antimycotic drugs viz., griseofulvin, 5-bromosalicyl-4-chloranilidine, acidum undecylenicum and nystatin.