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

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 – Gordonia sp. DSM44456 and Rhodococcus 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 Escherichia coli ATCC10536, Staphylococcus aureus DSM799, Candida albicans DSM1386, Alternaria alternata CBS1526, Fusarium linii KB-F1, and Aspergillus niger DSM1957. The best inhibitory effect was observed for all chalcones against E. coli 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 S. aureus DSM799 in comparison to their chalcones. Excluding the E. coli 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).