ABSTRACT
AIM To study the extraction process,enzymatic properties and practical application of glucuronic hydrolase in Scutellaria baicalensis stems and leaves(sbsl GUS).METHODS With granularity,water consumption,extraction time and extraction frequency as influencing factors,enzymatic activity as an evaluation index,the extraction process was optimized by orthogonal test on the basis of single factor test.The relationship between substrate(baicalin)concentration and enzymolysis rate,after which Vmax and Km were calculated,the effects of pH value,temperature and metal ion on enzymatic activity were investigated,pH stability and heat stability were evaluated.sbsl GUS was adotped in the enzymolysis of baicalin to prepare baicalein,then the effects of pH value,temperature,reaction time,initial substrate concentration and enzyme addition on transfer rate were investigated.RESULTS The optimal extraction process was determined to be 40 mesh for granularity,10 times for water consumption,15 min for extraction time,and 3 times for extraction frequency.The enzymolysis accorded with the kinetics of enzymatic reaction,Km was 0.006 3 mol/L,Vmax was 70.42 μmol/h,the strongest enzymatic activity was found at the pH value of 6.0,temperature of 45℃and metal ion of 100 mmol/L Cu2+,sbsl GUS demonstrated good stability at the ranges of 4.0-7.0 for pH value and 4-30℃for temperature.The optimal preparation process was determined to be 6.0 for pH value,45℃for temperature,more than 12 h for reaction time,67.2 mmol/L for initial substrate concentration,and 1 mL/0.269 mmol baicalin for enzyme addition,the transfer rate was 97.83%.CONCLUSION sbsl GUS enzymolysis exhibits high efficiency and mild condition,which can provide a simple preparation method for obtaining baicalein,and expand the application path of Scutellaria baicalensis stems and leaves.
ABSTRACT
Aim To explore the protective mechanism of tanshinone B on cognitive dysfunction in mice with vascular dementia.Methods C57BL/6 male mice were divided into control group, vascular dementia model group(VD group), tanshinone B group(TSB 2,4,8 mg·kg-1), donepezil hydrochloride group(1 mg·kg-1), according to the random number table method.The VD model was constructed by the coarctation of bilateral common carotid arteries in mice.Ten days after the successful modeling, the low, medium, and high-dose tanshinone B groups were intraperitoneally injected with tanshinone B, the positive control medicine group was intraperitoneally injected with donepezil hydrochloride, once a day, and the mice in control group and VD group were injected intraperitoneally with the same amount of normal saline for 20 d.Morris water maze test was used to detect the learning and memory ability of mice in each group; the cortex and hippocampus of each group were separated, and MDA, SOD and GSH-Px were determined by spectrophotometry; the pathological changes in the hippocampus of each group were observed by HE staining.The expression of p-LRP6, LRP6, Wnt1 and β-catenin protein in the hippocampus of each group of mice were detected by Western blot.Results Compared with control group, the ability of memory was reduced, the content MDA increased(P<0.01), SOD and GSH-Px activities decreased(P<0.01), and significant pathological damage in hippocampus, the expression of p-LRP6, Wnt1, and β-catenin protein was significantly reduced in VD group(P<0.01).Compared with VD group, the learning and memory abilities of the mice were improved, the content of MDA decreased(P<0.01), the activities of SOD and GSH-Px increased(P<0.01), and the pathological damage in hippocampus was significantly improved.The expression of Wnt1 and β-catenin protein increased significantly in TSB treatment group(P<0.01).Conclusions TSB can improve the cognitive dysfunction of VD mice, and its mechanism may be related to the activation of the LRP6/Wnt1/β-catenin pathway in hippocampus.