A Study on Synthesis and Antioxidant Activity Comparison of Novel Stilbenebenzamide Compounds

Background: Stilbene phytalexis (1,2-diphenyloethylen) and benzamide are beneficial for human health. To increase the stilbene ring activity, a new series of its derivatives containing benzamide structure was synthesized and evaluated for their in vitro antioxidant power. Methods: Methods: 1 H nuclear magnetic resonance, mass spectroscopy, and chromatographic analyses were used to confirm the successful synthesis. The antioxidant properties were determined by the elimination of O 2 ˙-, HO˙ , DPPH˙ , ABTS+˙ radicals, total antioxidant status (TAS) and the ferric reducing antioxidant activities (TAC) measurements. Results: Stilbenebenzamide compounds showed a wide spectrum of antioxidant ability; however, their total antioxidant power was weaker than those of butylated hydroxytoluene (BHT), ascorbic acid, and resveratrol. The highest antiradical activity towards O 2 ˙ and HO˙ was shown by the compounds with structures containing amine group (SBEBA, SBA) (O 2 ˙: 37.7 – 38.0% and 40.8 – 43.5%, HO˙ : 29.8%, 28.7% inhibition, respectively) at1.25 mM concentration. The antiradical power of SBEBA (0.29) in DPPH˙ assay was lower than those of resveratrol (1.83), ascorbic acid (3.63) and BHT (4.09). The TAS values of the synthesized compounds ranged from 152.9±5.3 to 240.2±6.7μM trolox equivalent/gram (TE/g) and were much lower than those of BHT (1304±43.0), reservatrol (1360±29.0) and ascorbic acid (2782±39.7) μM TE/g. Similarly, the TAC values ranging from 29.7±0.9 to 41.5±1.6 μM TE were weaker than that of resveratrol (239.2 ±6.7 μM TE/g). Conclusion: The results suggest that the presence of the hydroxyl group in the stilbene ring should be considered in the further design of stilbenebenzamide compounds to enhance their antioxidant activity.