OBJECTIVETo study the flavanoids extracted from onion on the blood-brain barrier (BBB) permeation, and their effects on primary cultured neuron cell proliferation and apoptosis of SD rats using ethanol reflux method.

METHODSThe brain microvascular endothelial cells (BMVECs) were first successfully primary cultured. Then rats BMVECs and astrocytes (ACs) were co-cultured to establish the in vitro BBB model. The flavanoids were extracted from onion using ethanol reflux method. The model was verified by transmission electron microscopy (TEM) and trans-epithelial electric resistance (TEER). The flavanoids permeability was tested using high performance liquid chromatography (HPLC). Meanwhile, rat neuron cells were cultured and exposed to H2O2 and flavanoids. Their effects on the cell proliferation and apoptosis were observed using MTT assay. The injury of neuron DNA was analyzed using single-cell gel electrophoresis (SCGE) and immunofluorescent assay.

RESULTSThe in vitro BBB model was successfully established by TEM and TEER. Results of HPLC proved flavanoids extracts could effectively permeate the BBB with the permeability of 60.58%. The extractive at 10 - 20 microg/mL showed obvious inhibition on the apoptosis of neuron cells induced by H2O2, and attenuated the injury of neuron DNA.

CONCLUSIONSThe flavanoids extracted from onion ethanol reflux method could effectively penetrate the BBB. They also showed obvious inhibition on the H2O2 induced neuron cell apoptosis and DNA injury.