Synthesis, characterization, in vitro antimicrobial and anticancer evaluation of random copolyesters bearing biscoumarin units in the main chains

Abstract

A series of aliphatic–aromatic random copolyesters bearing a biscoumarin group were synthesized by phase-transfer-catalyzed interfacial polycondensation of 3,3′-methylene-bis(4-hydroxycoumarin)1 and aromatic diols such as hydroquinone, resorcinol, ethyl resorcinol, bisphenol-A, and curcumin with sebacoyl chloride. These copolyesters were obtained with yields in the range between 76 and 85 % and the inherent viscosity between 0.22 and 0.33 dl/g. All the copolyesters were found to be soluble in chlorinated and polar aprotic solvents. The chemical structures of the copolyesters were analyzed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The physical properties of copolyesters obtained by altering the aromatic diols 3, were characterized by thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, and X-ray diffraction (XRD) technique. Copolyesters exhibited good thermal stability having a decomposition temperature above 223 °C. Copolyesters with the bisphenol group as backbone exhibited higher thermal stability than others. Results revealed that the copolyesters exhibit a glass transition temperature in the range of −11 to 54 °C. It was found that copolyester with ethyl resorcinol and curcumin shown low and high Tg values, respectively. XRD measurement revealed the amorphous nature of copolyester with a low degree of crystallinity. Agar disc diffusion method was employed to study the antimicrobial activity of these random copolyesters. The synthesized copolyester was subjected to in vitro anticancer activity against lung cancer (Hep-2) cell line.