Inhibition of LPS-induced expression of iNOS and COX-2 on extracts of Acanthopanax leucorrhizus (Oliv.) Harms stems

Abstract

Acanthopanax leucorrhizus is an endemic medicinal plant growing abundantly in the northwest region of China. The roots and stem barks have been widely used to treat rheumatism, numbness, contracture, quadriplegia, hemiplegia, traumatic injury, edema, and itchy skin, although the anti-inflammatory effects of the extracts of A. leucorrhizus have not been assessed until now. To investigate the anti-inflammatory effects on macrophages of various extracts from A. leucorrhizus stems, alterations in the inducible nitric oxide synthase (iNOS)-mediated cyclooxygenase-2 (COX-2) expression and inflammatory cytokine production were measured in lipopolysaccharide (LPS)-activated RAW264.7 cells. Briefly, the dichloromethane extract prepared from stems of A. leucorrhizus (ALSDC) effectively inhibited NO production in LPS-stimulated cells and significantly reduced the production of pro-inflammatory cytokines IL-6 and TNF-α at a dose of 40 µg/mL. We also confirmed a dose-dependent and significant inhibition of iNOS and COX-2 protein expression. In conclusion, ALSDC exerted strong inhibitory effect on the expression of iNOS and COX-2 protein in LPS-induced RAW 264.7 macrophages and these results provide strong evidence to suggest that ALSDC may be considered as an important candidate for the treatment of inflammatory-related diseases in the future.