Evaluation of anti-inflammatory potential of extract, fractions and major compounds of Ponciri Fructus in LPS-induced RAW 264.7 cells

Dried immature fruit of Poncirus trifoliata (L.) Raf., known as Ponciri Fructus, is a well-known traditional Korean medicine for treatment of allergy and gastrointestinal disorders. In previous study, we reported the anti-obesity effects of the extracts, fractions and major compounds of Ponciri Fructus on 3 T3-L1 preadipocytes. In continuation, in this research, we evaluated their anti-inflammatory potential using lipopolysaccharide (LPS) induced RAW 264.7 cells. Results showed that the ethanol extract of fruits and hexane and ethyl acetate soluble fractions of the extract inhibited nitrous oxide (NO) production in LPS stimulated macrophage in all doses. Whereas, butanol fraction of extract showed significant inhibition in production of NO only at higher dose of 80 & mu;g/mL. Some of the isolated compounds such as poncirin, naringin, imperatorin and phellopterin, significantly inhibited NO production in LPS-stimulated macrophages. Poncirin and imperatorin showed anti-inflammatory potential by inhibiting cyclooxygenase (COX)-2 protein as evidenced by downregulation of that protein in western blot assay. Imperatorin also inhibited inducible nitric oxide synthase (iNOS) responsible for production of NO in macrophages. In conclusion, Ponciri Fructus has strong anti-inflammatory potential and possesses many active flavonoids and coumarins contributing to this activity.