Caffeic Acid, One of the Major Phenolic Acids of the Medicinal Plant , Reduces Renal Tubulointerstitial Fibrosis.

The renal fibrotic process is characterized by a chronic inflammatory state and oxidative stress. () is a French medicinal plant found in Reunion Island and known for its antioxidant and anti-inflammatory activities mostly related to its high polyphenols content. We investigated whether oral administration of polyphenol-rich extract from could exert in vivo a curative anti-renal fibrosis effect. To this aim, three days after unilateral ureteral obstruction (UUO), mice were daily orally treated either with a non-toxic dose of polyphenol-rich extract from or with caffeic acid (CA) for 5 days. The polyphenol-rich extract from , as well as CA, the predominant phenolic acid of this medicinal plant, exerted a nephroprotective effect through the reduction in the three phases of the fibrotic process: (i) macrophage infiltration, (ii) myofibroblast appearance and (iii) extracellular matrix accumulation. These effects were associated with the mRNA down-regulation of , , and , as well as the upregulation of . Importantly, we observed an increased antioxidant enzyme activity for GPX and Cu/ZnSOD. Last but not least, desorption electrospray ionization-high resolution/mass spectrometry (DESI-HR/MS) imaging allowed us to visualize, for the first time, CA in the kidney tissue. The present study demonstrates that polyphenol-rich extract from significantly improves, in a curative way, renal tubulointerstitial fibrosis progression in the UUO mouse model.