Tibetan Medicine Tanguticus Green Gu Lan Extract Neuroprotective In The Rat Middle Cerebral Artery Occlusion (mcao) / Repair

Dracocephalum tanguticum Maxim (D. tangutium), also named Tangguteqinglan or Ganqingqinglan in Chinese, is a Tibetan herbal medicine which is used in the treatment of many diseases while is proved to be effective in anti-hypoxia in mice. Phytochemical analysis of D. tangutium showed that main chemical components are triterpene and flavonoids and notably D. tangutium contains more flavonoids than that of many traditional Chinese herbs. Total flavonoid assay showed that whole herb, crude extracts and BuOH-soluble fraction (DME) contained 8%, 15% and 52% flavonoids, respectively, whereas there were only 6% flavonoids in both CHCl3- and H2O- soluble fractions.In the present study, the potential antioxidant activities and neuroprotective or neurorestorative action of D. tangutium extract (DME), which contained 52% of total flavonoids, on cerebral ischemia injury in rats were assessed by in vivo experiments. RT-PCR and Western blot analysis showed that the extract (30 mg/kg/day for seven days) by intragastric administration modulated the mRNA expression and protein synthesis of two neurotrophic factors: brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3). DME was effective to stimulate BDNF mRNA expression and protein synthesis in the ipsilateral frontal cortex (IFC) of both sham-operated and permanent middle cerebral artery occlusion (pMCAO) rats and this effect was also observed in the hippocampus of pMCAO rats. Although DME had no effect on NT-3 expression in sham-operated groups, it significantly increased NT-3 mRNA expression and protein synthesis in IFC and hippocampus of pMCAO rats. Meanwhile, the extract also induced a moderate decrease in malondialdehyde contents in hippocampus in both sham-operated and pMCAO groups, and significantly attenuated the decreased activities of endogenous antioxidants (superoxide dismutase, glutathione peroxidase and catalase) in both IFC and hippocampus of rats after ischemia insult. These findings suggested that DME may be of value in the treatment of ischemia-induced brain damage through stimulation of antioxidant activity and neurotrophic factor synthesis.