RESUMO
Nitric oxide (NO) is synthesized in large quantities by activated inflammatory cells and has been demonstrated to be involved in the pathogenesis of acute and chronic inflammatory conditions. Seabuckthorn (SBT) has been used in traditional medicine systems for the treatment of various diseases like cardiovascular, pain relief, oral inflammation and promotion of tissue regeneration. The present study focuses on the effects of SBT leaf extract on NO production induced by lipopolysaccharide (LPS) in the murine macrophage cell line RAW 264.7. In addition, cell viability, free radical-scavenging activity and inducible nitric oxide synthase (iNOS) expression were also evaluated. Seabuckthorn leaf extract significantly inhibited the enhanced production of NO induced by LPS in a dose dependent manner. Treatment with SBT did not reduce cell viability at any dose used. The extract showed significant scavenging of NO radicals released by the NO donor. Treatment of macrophages with SBT leaf extract also caused a significant inhibition of iNOS activation. These observations suggest that the inhibition of net NO production by SBT leaf extract may be due to its scavenging activity and/or its inhibitory effects on iNOS activation. The study suggests that SBT leaf extract has significant anti-inflammatory activity and has potential for the treatment of inflammatory diseases.