Antiallergic effects of Scutellaria baicalensis on inflammation in vivo and in vitro

Ethnopharmacological relevanceScutellaria baicalensis (SB) is one of the most widely used medicinal herbs for the treatment of inflammation. In this study, we investigated the antiallergic effect of SB in vivo and in vitro.Materials and methodsSprague-Dawley (SD) rats received intradermal injections of anti-DNP IgE at each of three dorsal skin sites. Forty-eight hours later, each rat received an injection of DNP-HSA in saline containing 4% Evans blue through the dorsal vein of the penis. One hour before injection, SB extract was administered orally. The dorsal skin of the rats was removed and the pigment area measured. In addition, rat peritoneal mast cells (RPMCs) were cultured and purified to investigate histamine release. In vitro, human mast cells (HMC-1) were pretreated with SB extract for 30 min before stimulation with phorbol 12-myristate 13-acetate (PMA) plus A23187. The effects on pro-inflammatory cytokine expression and mitogen activated protein (MAP) kinase expression were investigated using TNF-α and IL-8 assays, and Western blotting analysis of HMC-1 cells.Results and conclusionsSB treatment inhibited the passive cutaneous anaphylaxis reaction compared to the control group, and histamine release decreased significantly following treatment of RPMCs with SB. In HMC-1 cells, SB restored IL-8 and TNF-α expression and inhibited MAP kinase expression in compound 48/80-induced HMC-1 cells. These data suggest that SB may prove to be a useful anti-inflammatory agent through its downregulation of the expression of various inflammatory mediators.

Graphical abstractScutellaria baicalensis (SB) treatment restored PCA reaction histamine release in DNP IgE-induced rats. In addition, SB restored the production of interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha expression as well as the MAP kinases expression in compound 48/80-induced human mast cell (HMC)-1 cells.Download high-res image (143KB)Download full-size image