Synthesis, FT-IR Spectroscopic Studies and in vitro FRAP Assay of some Chalcone Derivatives and their Metal Complexes

Abstract

A variety of substituted chalcones, namely, 3”-aminochalcone, 2”,4”- dichlorochalcone, 2”-methoxychalcone, 4”-methoxychalcone and 2”- hydroxychalcone have been synthesized by Claisen-Schmidt condensation and characterised by melting point and FT-IR spectroscopic technique. The tin(II), cadmium(II) and copper(II)) complexes of the 2”-hydroxychalcone (4E2HC) with the formula [M(L)2] were subsequently prepared. The 2”- hydroxychalcone and its metal complexes were evaluated for in vitro radical scavenging activity by carrying out ferric reducing antioxidant power (FRAP) assay. In almost all cases, the metal complexes exhibited higher activities than the ligand (chalcone). Notable activity (11.63 µM) was observed for the cadmium complex of the 4-ethoxy-2”-hydroxychalcone at 10 µg/mL. Limited structure–activity relationship (SAR) was established by considering the effect of different groups attached to the aryl rings and the metal centers on varying antioxidant activity. The enhanced activity may be due to the presence of electron-rich metals and electron-releasing ethoxy (- OC2H5) and hydroxy (–OH) groups. The confirmed bioactive compounds from this study can be used as effective template in medicinal chemistry for drug discovery.