Validamycin A, a fungicidal, is an agricultural antibiotic. Validamycin A is originally isolated from Streptomyces hygroscopicus var. limoneus. Validamycin A inhibits the growth of A. flavus, with a MIC of 1?μg/mL. Validamycin A shows potent inhibitory activity against trehalase of Rhizoctonia solani, with an IC50 of 72 μM[2]. Validamycin A is a reversible tyrosinase inhibitor, with a Ki of 5.893 mM.IC50 & Target:Antibiotic, IC50: 72 μM (trehalase)[2], Ki: 5.893 mM (tyrosinase)In Vitro: Validamycin A (0.5-1 μg/mL; 18 hours) inhibits the growth of A. flavus and delayed conidial germination.
Validamycin A shows no cytotoxicity to human bronchial epithelial cells.
Validamycin A directly binds to several residues in the active site of tyrosinase, including HIS85, HIS244, GLU256, HIS259 and ASN260.