Coumaric acid from M. polymorphum extracts reverses the activated state of hepatic stellate cells (GRX) and inhibits their proliferation by decreasing the p53/p21 pathway.

Coumaric acid is a phenolic compound found in medicinal plants. Its use has been reported in the treatment of inflammatory diseases, prevention of alterations induced by oxidative stress, as well as acetaminophen-induced hepatotoxicity. Thus, this study evaluated coumaric acid as a potential treatment for liver fibrosis. Cell proliferation was assessed by the trypan blue exclusion technique and the cytotoxicity of coumaric acid was performed using an LDH assay. Mechanisms of cell apoptosis were evaluated by flow cytometry. The expression of genes associated with apoptosis, cell cycle control, and fibrosis was assessed by qPCR. The production of lipid droplets was quantified by oil red staining. The experiments performed showed that the treatment with coumaric acid was able to reduce cell proliferation without causing cell cytotoxicity or apoptosis. Coumaric acid was able to inhibit the expression of cyclin D1 and CDK's (CDK2, CDK4, and CDK6), increasing p53 and p21, which could lead to cell cycle arrest. Treatment with coumaric acid was also able to revert the activated phenotype of GRX cells to their quiescent state. Thus, our results suggest that coumaric acid has a potential therapeutic effect against liver fibrosis.