Effects of Microbial Transformation on the Biological Activities of Prenylated Chalcones from .

Microbial transformation is an alternative method for structural modification. The current study aimed at application of microbial transformation for discovering new derivatives and investigating the structure-activity relationship of isobavachalcone (), 4-hydroxyderricin (), and xanthoangelol () isolated from the herb . In the initial screening process, - were incubated with microbes using a two-stage fermentation method and analyzed through TLC monitoring. The screening results showed that and were able to transform and , respectively. Additionally, and var. were able to transform . Following scale-up fermentation, four new (, , , and ) and five known (, , , , and ) metabolites were produced. Cytotoxicity of all the compounds (-) was investigated using three human cancer cell lines including A375P, HT-29, and MCF-7 by MTT method. Meanwhile, the tyrosinase inhibitory activity of - was evaluated using l-tyrosine as a substrate. Overall, and displayed the highest cytotoxicity, and and exhibited the most potent tyrosinase inhibitory activity with relatively low cytotoxicity. This allowed us to postulate that the introduction of 4'--glucopyranosyl group led to the reduction in cytotoxicity and improvement in tyrosinase inhibitory activity.