Anti-inflammatory effect of auraptene extracted from trifoliate orange (Poncirus trifoliate) on LPS-stimulated RAW 264.7 cells.

Poncirus trifoliate is a traditional Chinese medicinal plant used for treating inflammation-related diseases for a long time and trifoliate orange contains abundant auraptene. The present study was to evaluate auraptene as a potential anti-inflammatory agent and investigate the mechanism of auraptene against prostaglandins E2 (PGE2) and cyclooxygenase-2 (COX-2) on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells by comparing it with aspirin as a positive control group. The methods of enzyme-linked immunosorbent assay, reverse transcriptive polymerase chain reaction, real-time PCR, and western-blotting were used in the study. The results showed that auraptene exhibited better biocompatibility and lower cytotoxicity. At the same time, it significantly inhibited the production of PGE2 on LPS-stimulated macrophage cells. The auraptene-treated group had a higher COX-2 mRNA expression but relatively lower COX-2 protein level which implied that auraptene suppressed the post-transcriptional expression of COX-2 protein but not the transcriptional process. Compared with aspirin, the lower cytotoxicity of auraptene can make it a potential source for medicine that can benefit patients who are suffering from chronic inflammatory diseases and need long-term medication.