Immunomodulatory and Anti-inflammatory Effect of p-Coumaric Acid, a Common Dietary Polyphenol on Experimental Inflammation in Rats

ABSTRACT In this study, p -coumaric acid was evaluated for its immunomodulatory and anti-inflammatory properties in vivo . The immunomodulatory effect of p -coumaric acid (100 mg/kg body weight) was assessed by evaluating its effect on cell-mediated immune responses (delayed type hypersensitivity reaction), serum immunoglobulin levels, and macrophage phagocytic index in rats. The anti-inflammatory effects of p -coumaric acid (100 mg/kg body weight) were investigated by examining its effect on expression of tumor necrosis factor (TNF-α) in synovial tissue by immunofluorescence confocal microscopy and circulating immune complexes in serum of adjuvant-induced arthritic rats. The increased cell-mediated immune responses and macrophage phagocytic index observed in control rats were significantly reduced ( p