Optimization of Extraction Technology of Total Flavonoids Psidium guajava Leaves by Box-Behnken Design-Response Surface Method and the Effects of Total Flavonoids on Glucose Tolerance in Diabetic Model Mice / 中国药房

ABSTRACT

OBJECTIVE:To optimize the extraction technology of total flavonoids from Psidium guajava leaves and investigate the effects of total flavonoids from P guajava leaves on glucose tolerance in diabetic model mice.METHODS:Based on single factor test,using extraction time,solid-liquid ratio and the amount of ethanol as independent variables,comprehensive scores of the yield of hyperin,quercetin-3-O-β-D-arabinopyranoside,quercetin-3-O-α-L-furanarabino side ethyl acetate and extract as dependent variable,Box-Behnken design-response surface method was used to optimize the reflux extraction process of total flavonoids from P guajava leaves,and validation test was also conducted.Sixty mice were randomly divided into blank group,model group,metformin group (170 mg/kg),P.guajava leaves total flavonoids low-dose,medium-dose and high-dose groups (23.41,46.81,93.62 mg/kg,by the content of total flavonoids),with 10 mice in each group.Except for blank group,diabetic model was induced in those groups,and then model mice were given relevant medicine intragastrically once a day for consecutive 21 d,6 h after last medication given glucose 2.0 g/kg intragastrically.The levels of blood glucose were determined 0,0.5,1.0,2.0 h after intragastric administration of glucose,and the area under the curve (AUC) of blood glucose was calculated.RESULTS:The optimal technology of P guajava leaves total flavonoids was as follows as extracting twice,lasting for 1.0 h each time,solid-liquid ratio of 1 ∶ 17,ethanol volume fraction of 56％.In validation test,the contents of hyperin,quercetin-3-O-β-D-arabinopyranoside and quercetin-3-O-α-L-furanarabino side ethyl acetate were 2.57,3.38,2.26 mg/g(RSD＜2％,n=3);the yield of extract was 25.71％ (RSD=1.19％,n=3);average comprehensive score was 96.41 (RSD=l.34％,n=3);relative error was 3.57％ with the predicted value of 99.98.Compared with blank group,AUC of mice were increased significantly in each group;compared with model group,AUC of metformin group,P.guajava leaves total flavonoids medium-dose and high-dose groups were all decreased significantly,with statistical significance (P＜0.05 or P＜0.01).CONCLUSIONS:The optimal extraction technology is stable,feasible and controllable in quality.Total flavonoids from P.guajava leaves can promote the recovery to normal level of blood glucose.