Honokiol: an effective inhibitor of high-glucose-induced upregulation of inflammatory cytokine production in human renal mesangial cells

To evaluate the regulatory effects of honokiol on high-glucose (HG)-induced inflammatory responses of human renal mesangial cells (HRMCs). We performed MTS assays to determine the non-cytotoxic concentration of honokiol for HRMCs. Enzyme-linked immunosorbent assays were performed to analyze the expressions of the proteins interleukin (IL)-1 beta, IL-18, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta 1, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1 alpha, RANTES, and prostaglandin (PG) E2. The total nitric oxide (NO) concentration was determined using the Griess reaction. Treatment with 50 mmol/L glucose markedly increased the level of IL-1 beta, IL-18, TNF-alpha, PGE2, NO, TGF-beta 1, MCP-1, MIP-1 alpha, and RANTES. Honokiol (similar to 20 mu mol/L) treatment inhibited the HG-induced expression of inflammatory cytokines such as IL-1 beta, IL-18, TNF-alpha, PGE2, NO, and TGF-beta 1 in a dose-dependent manner. Moreover, it markedly inhibited the expression of chemokines such as MCP-1, MIP-1 alpha, and RANTES, which are upregulated under HG conditions. Honokiol inhibits the HG-induced expression of inflammatory factors in HRMCs. Honokiol may be considered a promising drug with potent anti-inflammatory activities in addition to its strong anti-cancer, anti-angiogenesis, and anti-neurodegenerative effects.