Inhibitory effects of a spinasterol glycoside on lipopolysaccharide-induced production of nitric oxide and proinflammatory cytokines via down-regulating MAP kinase pathways and NF-κB activation in RAW264.7 macrophage cells

Extracts from the leaves of Stewartia koreana are known to exhibit strong anti-inflammatory activity. Investigation of bioactive compounds from S. koreana has led to the isolation of 3-O-beta-D-glucopyanosylspinasterol (spinasterol-Glc), a spinasterol glycoside. In the present study, we examined the effects of spinasterol-Glc on production of nitric oxide (NO) and proinflammatory cytokines in LPS-treated RAW264.7 macrophage cells and in mouse models. Our results showed that spinasterol-Glc inhibited the production of NO and proinflammatory cytokines such as TNF-alpha, IL-6 and IL-1 beta in dose-dependent manners in LPS-treated RAW264.7 cells. Spinasterol-Glc inhibited the expression of iNOS and the proinflammatory cytokine genes. Spinasterol-Glc also inhibited phosphorylation of I kappa B-alpha and IKK alpha/beta as well as translocation of NF-kappa B to the nucleus. We demonstrated that spinasterol-Glc reduced transcription of the NF-kappa B minimal promoter and NF-kappa B DNA binding activity. Administration of the spinasterol-Glc significantly decreased the plasma levels of these inflammatory mediators including TNF-alpha, IL-6 and IL-1 beta in LPS-injected mice and improved survival of septic mice with lethal endotoxemia. These results suggest that spinasterol-Glc has effective inhibitory effects on production of inflammatory mediators via inhibition of MAP kinases/NF-kappa B activities, and can be used as a potential anti-inflammatory agent for the prevention and treatment of inflammatory diseases. (C) 2012 Elsevier B.V. All rights reserved.