Microbial transformations of 4′-methylchalcones as an efficient method of obtaining novel alcohol and dihydrochalcone derivatives with antimicrobial activity

Abstract

Biotransformations are an alternative method of receiving dihydrochalcones as a result of the reduction of α,β-unsaturated ketones - chalcones. In presented research, two strains of bacteria - <i>Gordonia</i> sp. DSM44456 and <i>Rhodococcus</i> sp. DSM364 - were selected as effective biocatalysts that are able to transform chalcones in a short period of time. As a result of our investigation 3 new dihydrochalcones and one novel alcohol were obtained with high isolated yields. All 4'-methylchalcone derivatives and biotransformations products were tested for antimicrobial activity against <i>Escherichia coli</i> ATCC10536, <i>Staphylococcus aureus</i> DSM799, <i>Candida albicans</i> DSM1386, <i>Alternaria alternata</i> CBS1526, <i>Fusarium linii</i> KB-F1, and <i>Aspergillus niger</i> DSM1957. The best inhibitory effect was observed for all chalcones against <i>E. coli</i> ATCC10536 - compounds 1-6 and 8 prevented thorough growth of this strain (ΔOD = 0). Moreover, dihydrochalcones showed about 2-3 times stronger inhibitory effect against <i>S. aureus</i> DSM799 in comparison to their chalcones. Excluding the <i>E. coli</i> ATCC10536 strain, 3-(4-carboxyphenyl)-1-(4-methylphenyl)propan-1-ol (8b) had weaker biological activity than 4-carboxy-4'-methyl-α,β-dihydrochalcone (8a).