The Calycosin Extraction Process Optimization And On Cerebral Ischemia Injury In Rats

Astragali Radix, the dry root of Astragalus membranceus (Fisch) Bge, known as Huangqi in China, as a primary Chinese tonic herb has been used for centuries. Calycosin, an isoflavonoid, is the major active component in Astragali Radix. Calycosin displayed beneficial effects such as antioxidation, antitumor, anti-ischemia, inhibition of hyperpermeability induced by low osmolarity, neuroprotective activity and scavenging free radicals.The present study was to optimize the extraction technology of total calycosin from Huangqi by response surface analysis methodology (RSM), and to investigate the neuroprotective effect and mechanisms of calycosin in focal cerebral ischemia.1. Response surface analysis methodology (RSM) was used to increase the extraction technology of total calycosin from Huangqi. Methods:On the basis of single-factor experiments, the Box-Behnken center-united experimental design principles were used to design the experiments and the response surfaces analysis of 4 factors, including extracting time (XI), extracting temperature (X2), ethanol concentration (X3) and water to material ration (X4), and 3 levels were adopted respectively. The optimal extraction conditions were as following:X1 is 2.5h,X2 is 69℃,X3 is 90%, X4 is 22ml/g.2. Calycosin had a significant neuroprotective effect against cerebral ischemia-reperfusion injury. Methods:To investigate the neuroprotective effects of different doses of calycosin, sprague-dawley (SD) rats were subjected to transient middle cerebral artery occlusion for 120min, and they were treated with calycosin or vehicle before the ischemia and at the onset of reperfusion. Neurologic deficit scores and infarct volume were assessed. Results:Calycosin had protective effects on focal cerebral ischemia damage, as the optimum dose to 1.0mg/kg.3. To explore the neuroprotective mechanism of calycosin on cerebral ischemia-reperfusion damage in rats. Preoperation and postoperation 6h,24h,48h, brain tissue homogenate were collected in order to measure the contents of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) and maleic dialdehyde (MDA). Results:The vitality of SOD, CAT, GSH-PX were increased significantly but the content of MDA was decrease in ischemia brain tissue in the calycosin group, compared with those in MCAO group, and its mechanism may be related to the increase of antioxidase vitality and reduce of oxygen free radicals.