Synthesis and Biological Activities of 3,5-Disubstituted-4-Hydroxycinnamic Acids Linked to a Functionalized Coumarin

Abstract

As part of our interest in the coumarin chemical nucleus, a series of 3,5-disubstituted-4-hydroxycinnamic acids to which 6-hydroxy-7-methoxy-4-methyl-3-isopropylcoumarin is grafted was synthesized via a straightforward synthetic method. Chemical identities of the synthesized conjugates were specified by analyzing their FTIR, 1H-NMR, and 13C-NMR spectra. Three biological activities were investigated for the final products along with that of the functionalized coumarin itself, which are: antioxidant, exploratory antitumor, and antimicrobial activities. The first activity was screened via DPPH test, while the second one was tested by a well-documented MTT assay against the following cell lines: SKG, AMN3, MCF-7, and HeLa. Third activity was assessed by an agar disk diffusion method versus four standard bacterial strains and two standard fungal strains. The test pathogens included Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Haemophilus influenzae, Aspergillus niger, and Candida albicans. The outcomes assumed from the antioxidant activity assay indicated that M2 has a better activity and M5 has less activity than the other synthesized conjugates, the same outcome is documented from studying the exploratory antitumor activity. Concerning the antimicrobial activity, the prepared conjugates, as well as the functionalized coumarin, showed an acceptable activity with an ascendant effect attributed to M1. Based on these findings, it is concluded that the synthesized conjugates M1 and M2may be good candidates as antimicrobial and antitumor agents, respectively. Also, these conjugates may provide new scaffolds for the development of modern therapeutic agents.