| Cornus officinalis Sieb.et Zucc.is the perennial woody plant in Cornaceae family and Cornus genus,the officinal parts are the dry pericarp of fruit.Cornus officinalis has the efficiency of reinforcing liver,benefiting kidney,astringency and stypsis,which is widely used in the traditional formula of traditional Chinese medicine(TCM)and clinical.It is mainly distributed in Henan,Shaanxi,Anhui,Zhejiang and so on,gives priority to with artificial cultivation.Present studies showed that saponins is one of the important biological active ingredients of Cornus officinalis,which had the effect of regulating immune function,protecting livers,anti-arrhythmia and treating the diabetes complications.However,the lack of systematic research in the hypoglycemic mechanism limited its development and utilization in the treatment of diabetes.In this study,firstly,ultrasonic-microwave synergistic extraction on total saponins from Cornus officinalis has been optimized using the method of response surface.The HPD-300 macroporous resin was used to remove the polysaccharides,pigments and other impurities in alcohol extractive,which increased the purification and yield of total saponins.Secondly,the total saponins contents of Cornus officinalis has been determined from different habitats,to explore the effects of geographical factors on total saponins contents and the correlation between them.The results showed that the differences of total saponins contents among 15 habitats were significant.Finally,the type 2 diabetes mice induced by high fat and high sugar diet with streptozotocin(STZ)were used to investigate the effect of different doses of total saponins on glucose metabolism.In addition,this study focus on Cornus officinalis total saponins potential mechanism of lipid metabolism,liver inflammation,and oxidative stress,key gene mRNA expression on skeletal muscle metabolism,seeking theoretical evidence and database for clinical practice.The main results of this experiment were as follows:(1)The ultrasonic-microwave synergistic extraction process of the total saponins from Cornus officinalis was studied in this paper.The optimum combination of extraction parameters were as follows:solvent to sample ratio 1:21;microwave power 417 W;ultrasonic power 369 W and extraction time 5 min.The result increased 28.43%and 24.98%respectively relatived to ultrasonic extracting method and microwave extracting method.(2)The best conditions of HPD-300 macroporous resin enriched and purified the total saponins of Cornus officinalis were as follows:adsorption conditions were 3.5 mg/mL and pH 7.0 total saponins extractive,the flow velocity was 2 BV/h,the maximum injection volume was 6 BV.Desorption conditions were 3.5 BV 50%ethanol after 3 BV distilled water elution to remove impurities at the flow velocity of 1.5 mL/min.Total saponins purification dramatically increased from 6.23%to 37.36%,raised six times compared with the original purity.(3)The total saponins contents of Cornus officinalis has been determined from different habitats,the results showed that the differences of total saponins contents among 15 habitats were significant.Among 15 different habitats,the highest total saponins contents were Xixia county of Henan province(26.65 mg/g)and Foping county of Shaanxi province(25.80 mg/g),whereas the lowest was Shitai county of Anhui province(13.55 mg/g).The total saponins contents were positively correlated with altitude and negatively with longitude.Furthermore,the cluster analysis revealed the total saponins contents were significant between eastern and western habitats.In general,the western habitats had higher total saponins contents.(4)The pharmacology experiment of total saponins from Cornus officinalis were as follows.In terms of glucose metabolism and pancreatic pathology in type 2 diabetes mice,total saponins significantly reduced fasting blood glucose(FBG)and insulin resistance index(IRI),improved the glucose tolerance,increased insulin secretion and sensitivity,protected islet cells from damaging,the mechanism maybe referred to improving insulin resistance,protection of islet function.The effect on lipid metabolism and liver pathology and morphology in experimental diabetes mice,total saponins dramaticlly improved blood fat index(TGS TC,HDL-C,LDL-C),protected the liver function and its mechanism related to relieving insulin resistance via improving lipid toxicity.In the field of liver inflammation and oxidative stress,total saponins significantly reduced the diabetes mice liver tissue inflammation factor(IL-6,TNF-?,CRP)levels,increased SOD activity,its function was to resist inflammation and reduce oxidative stress to improve the hepatic insulin resistance.In terms of the key target gene expression,total saponins significantly increased diabetes mice skeletal muscle GLUT-4,INSR,PI-3K,AKT gene mRNA expression in comparison to model group,improved glucose utilization in skeletal muscle,which is related to the mechanism of insulin resistance in diabetes mice.The above effects to a certain extent were dose dependent. |
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