Synthesis and biological evaluation of novel hybrid compounds derived from gallic acid and the 2-aminothiophene derivatives

Abstract

Gallic acid (GA) and its benzamide derivatives have a wide variety of biological activities, such as antimicrobial, antioxidant, anticancer. In this study, we have reported the synthesis of some new hybrid compounds comprised of the 2-aminothiophene and GA moieties and evaluation of their cytotoxic activities against HeLa (cervical cancer), HCT116 (human colon cancer), and FT (fibroblast) cell lines as well as antimicrobial activities against some Gram-positive and Gram-negative bacteria. The reaction of some 2-aminothiophene derivatives (previously prepared from the Gewald reaction) with galloyl chloride having the acetylated hydroxyl groups and the subsequent deprotection of the hydroxyl groups gave the desired hybrid compounds. Then, the antimicrobial activity of the compounds was evaluated using disc diffusion and minimum inhibitory concentration assays. Finally, the MTT assay was carried out to evaluate the cytotoxicity of the synthesized compounds on the mentioned cell lines. The structure of the synthesized compounds was elucidated by conventional spectroscopic methods such as NMR, FT-IR, and UV–Vis spectroscopy. All compounds prevented the growth of Staphylococcus coagulase more than the positive control of chloramphenicol, and one compound was more sensitive to the growth of Klebsiella pneumonia compared to the standard antibiotic. All compounds showed acceptable activity against cancer cells. The highest activity was observed against HeLa with an IC₅₀ value of 3.2 μg/mL for compound 3d and against HCT116 with IC₅₀ of 59.4 μg/mL for 3b. The high anticancer activity of compound 3d against HeLa allows us to consider it as a good lead compound for the development of new potent anticancer agents for the treatment of cervical cancer.

Graphic abstract