A comparative study of caffeic acid and a novel caffeic acid conjugate SMND-309 on antioxidant properties in vitro

► SMND-309, a new compound, is a conjugate of caffeic acid. ► Caffeic acid is an effective antioxidant. ► We compared in vitro antioxidant properties of SMND-309 with caffeic acid. ► In some assay systems, SMND-309 was more powerful than caffeic acid. ► The antioxidant properties of SMND-309 were concentration dependent.