Inhibitory effect of Sorbus commixta extract on lipopolysaccharide-induced pro-inflammatory events in macrophages

Sorbus commixta has been known as enthopharmacologically valuable plant in Korea, China and Japan. This plant has been reported to display numerous pharmacological activities such as anti-oxidative, anti-ice nucleation, anti-vascular inflammation, anti-lipid peroxidation, anti-atherogenic, and vasorelaxant effects. Although numerous pharmacological potentials have been demonstrated, immunomodulatory effect of this plant has not been fully elucidated yet. To evaluate its antiinflammatory activity, macrophages activated by lipopolysaccharide (LPS) were employed and the production of inflammatory mediators was explored in terms of understanding its molecular inhibitory mechanism. 70% ethanol extract (Sc-EE) from S. commixta strongly suppressed the production of nitric oxide (NO) and prostaglandin (PG) E2 but not tumor necrosis factor (TNF)-α. The extract also clearly diminished the mRNA levels of inducible NO synthase (iNOS) and cyclo-oxygenase (COX)-2, implying that the inhibition occurs at the transcriptional level. Indeed, Western blot analysis and luciferase activity assay revealed that Sc-EE remarkably suppressed AP-1 translocation and its activity, respectively. In agreement, this extract strongly suppressed the phosphorylation of JNK, a prime enzyme responsible for AP-1 translocation. Therefore, our results suggest that Sc-EE can be applied as an anti-inflammatory herbal medicine. To prove this possibility, in vivo efficacy test will be further continued in the following project.