Synthesis of Mono-Ketone Curcumin Analogs from 3-Benzyloxybenzaldehyde and their Activity Assay as Inhibitor of α-Amylase

Abstract

Synthesis, characterization, and biological evaluation of mono-ketone curcumin analogs as an inhibitor of α-amylase enzyme have been conducted. This research was initiated by synthesizing 3-benzyloxybenzaldehyde from 3-hydroxybenzaldehyde using benzyl chloride, potassium iodide, and potassium carbonate in dimethylformamide under reflux condition for an hour. Synthesis of monoketone curcumin analogs was performed through Claisen-Schmidt reaction by refluxing 3-benzyloxybenzaldehyde with acetone (analog A), cyclopentanone (analog B), and cyclohexanone (analog C) using potassium hydroxide 5% as a catalyst for an hour. The structures of the products were elucidated by FTIR, MS/MS, 1H-NMR, and 13C-NMR. Mono-ketone curcumin analogs were evaluated for their activity assay towards inhibition of α-amylase enzyme. The inhibition type of mono-ketone curcumin analogs was also investigated. The inhibition results of monoketone curcumin analogs were compared to acarbose as a positive control. The results showed that 3-benzyloxybenzaldehyde and mono-ketone curcumin analogs (A, B, and C) yielded in 90.2, 89.7, 97.4, and 94.6%, respectively. The inhibitory activity of curcumin analog C was higher than the acarbose and other curcumin analogs (A and B). The inhibition types of mono-ketone curcumin analogs (A, B, and C) and acarbose were considered as uncompetitive inhibitors.