Biotransformation of newly synthesized coumarin derivatives by Candida albicans as potential antibacterial, antioxidant and cytotoxic agents

In this study, one bioactive coumarin analog was obtained as a result of biotransformation of three inactive coumarin derivatives by free cells of Candida albicans. The bioactive analog was purified by Column chromatography and HPLC. The presence of coumarin moiety in the biotrasformed product was confirmed by λ_max at 350–400 nm and FT-IR spectrum. The structure of the purified compound established by LC–MS and ¹H NMR suggests the chances of biotransformation of 7-(3-(Cyclopropylamino)-2-hydroxypropoxy)-4-methyl-2H-chromen-2-one (MW 289 Da) into 7-(3-Cyclopropylamino-2-hydroxy-propoxy)-4-methoxymethyl-chromen-2-one or 7-(3-Cyclopropylamino-2-methoxy-propoxy)-4-hydroxymethyl-chromen-2-one as a main product (MW 318 Da). The extra peak of 332 Da in LC–MS further confirms the presence of small proportion of 7-(3-Cyclopropylamino-2-methoxy-propoxy)-4-methoxymethyl-chromen-2-one apart from the main product. Oxidation followed by methylation reaction might be responsible for this conversion. The biotransformed product showed antimicrobial activity against Bacillus pumilus, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae and Salmonella typhi followed by decent antioxidant activity (6.756 μg IC₅₀). The efficacy of coumarin-analog on cellular proliferation was found at 40 μM concentration against human breast cancer MDA-MB-231 cells in MTT assay, which is insignificant against normal breast tissue MCF-10A cells at the same concentration. These findings suggest the potential use of C. albicans for achieving pharmacologically active coumarin analogs showing antibacterial, antioxidant and cytotoxic activity.