In Vivo and In Vitro Anti-inflammatory Effects of Ethanol Fraction from Periploca forrestii Schltr.

Objective: To determine the anti-inflammatory effects of an ethanol fraction of Periploca forrestii Schltr. (EFPF) and to investigate the potential mechanisms underlying in vivo and in vitro models. Methods: The anti-inflammatory effects of EFPF were evaluated using the xylene-induced mouse ear edema and carrageenan-induced rat paw edema models in vivo. In vitro, RAW264.7 cells were exposed to 0-800 mu g/mL EFPF and the cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Then cells were treated with different concentrations of EFPF (100-400 mu g/mL) and stimulated with lipopolysaccharide (LPS, 1 mu g/mL) for 24 h. The supernatant was analyzed for nitric oxide (NO) using the Griess reagent, and the levels of inflammatory mediators and cytokines were determined using enzyme-linked immunosorbent assays for prostaglandin E-2 (PGE(2)), tumor necrosis factor alpha (TNF-alpha), interleukin (IL) 6, and IL-10. The protein expressions of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-kappa B), and mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK were examined by Western blot. Results: Compared with the control group, EFPF significantly reduced mouse ear edema and rat paw edema rate (P<0.05 or P<0.01). Compared with the LPS group, EFPF significantly inhibited the LPS-stimulated production of NO, PGE(2), TNF-alpha and IL-6 (P<0.05 or P< 0.01), and increased the IL-10 production (P< 0.05). EFPF also significantly inhibited LPS-induced protein expressions of iNOS and COX-2, suppressed the phosphorylation and degradation of inhibitor of NF-kappa B-alpha, decreased p65 level, and inhibited the phosphorylation of p38, ERK1/2 and JNK (P< 0.05 or P< 0.01). Conclusion: EFPF exerted anti-inflammatory effect by reducing protein expressions of iNOS and COX-2 and the production of the inflammation factors, including TNF-alpha, IL-6, NO and PGE(2), mainly through inhibition of LPS-mediated stimulation of NF-kappa B and MAPK signaling pathways.