Potential antioxidants and tyrosinase inhibitors from synthetic polyphenolic deoxybenzoins

Abstract

Deoxybenzoins (DOBs) are one-pot synthetic precursors of isoflavones with feature analogous to those beneficial polyphenols such as resveratrol (stilbene) and phloretin (dihydrochalcone). In this study, seventeen polyphenolic DOBs were synthesized and evaluated by various antioxidant assays and tyrosinase inhibitory effect in vitro. Results displayed that these DOBs are powerful antioxidants; for example, 2,3,4-trihydroxy-3′,4′-dimethoxydeoxybenzoin possesses an excellent anti-lipid peroxidation activity (IC 50 = 0.72 ± 0.16 μM), whilst 2,4,4′,5-tetrahydroxydeoxybenzoin showed good DPPH radical scavenging activity (IC 50 = 0.69 ± 0.04 μM), which were better than Trolox and vitamin C. Besides exhibiting a weak metal chelating effect, these DOBs were effective in scavenging ABTS + and superoxide anion ( O 2 - ) radicals. DOBs also exhibited potent mushroom tyrosinase inhibitory activity; for example 2,3,4′-trihydroxy-4-methoxydeoxybenzoin displayed stable and significant inhibitory effect on tyrosinase activity, with IC 50 values 43.37, 43.10 and 46.10 μM at incubation intervals of 0.5, 1.5, and 2.5 h, respectively. These results suggest that, with the advantage of being readily synthesizable small molecules, DOBs can be potentially developed into clinical and industrial antioxidants.