Synthesis of promising brominated flavonoids as antidiabetic and anti-glycation agents.

Twelve selected natural flavonoids (F1-F12) and their brominated derivatives (F1a-F12a) were investigated for their antidiabetic effects on α-glucosidase and α-amylase, as well as anti-glycation activity. The semisynthetic brominated flavonoids (F1a-F12a) were synthesized using brominating agents. Among the semisynthesized compounds, two semisynthetic compounds including 6,8-dibromoluteolin (F3a) and 6,8-dibromoalpinetin (F10a) were reported as new compounds. 8-Bromobaicalein (F4a, IC(50) = 0.52 ± 0.05 µM) and 6,8-dibromoluteolin (F3a, IC(50) = 0.99 ± 0.12 µM) were found as mixed-type potent agents on α-glucosidase and α-amylase inhibitory activities, respectively. In addition, 6,8-dibromochrysin (F1a, IC(50) = 50.90 ± 0.98 µM) was found to be the most potent compound for inhibiting Bovine Serum Albumin - glycation (BSA-glycation) mediated methylglyoxal. The results of this study indicated that the introduction of bromine into flavonoids could benefit antidiabetic and anti-glycation due to the influence of the electronic effect and hydrophobic properties of bromine atoms.