Nicotiflorin reduces cerebral ischemic damage and upregulates endothelial nitric oxide synthase in primarily cultured rat cerebral blood vessel endothelial cells

Nicotiflorin is a flavonoid glycoside extracted from a traditional Chinese medicine Flos Carthami. In the current study, we investigated the neuroprotective effect of nicotiflorin on a transient focal cerebral ischemia–reperfusion model in rats. Nicotiflorin (2.5–10 mg/kg) administered after onset of ischemia markedly reduced brain infarct volume by 24.5–63.2% and neurological deficits. Also the effect of nicotiflorin on endothelial nitric oxide synthase (eNOS) activity, mRNA and protein expression after hypoxia–reoxygenation (H–R) treatment was investigated in an in vitro model mimic cerebrum ischemia–reperfusion in vivo. After total 4 h hypoxia and 12 h reoxygenation, eNOS activity, mRNA and protein levels in the primarily cultured rat cerebral blood vessel endothelial cells treated with nicotiflorin (25–100 μg/ml) 2 h after onset of hypoxia were significantly higher than eNOS activity, mRNA and protein levels in the pure H–R cells and also higher than eNOS activity, mRNA and protein levels in cells cultured under normoxic conditions. The results demonstrated that nicotiflorin had a protective effect against cerebral ischemic damage. The results also gave an important elucidation for the mechanism underlying the protective effect at the cellular level.