| Pharmacopoeia recorded that propolis has the efficacy of anti diabetes, according to this feature we found that the catechol structure of active ingredient CAPE (caffeic acid phenethyl ester) has the effect of antioxidation. Because of the low level of antioxidant enzymes secreted by pancreatic islets B cells, high concentration of ROS can cause dysfunction of islet B cells and weaken the effect of insμLin. Researches have shown that Nuclear factor erythriod 2-related factor 2 can protect islet B cells, also can induce antioxidase expression and maximize the secretory function of islet B cells in patients with type two diabetes. Enough evidence has shown that antioxidant has become a new target of diabetes, and CAPE is an agonist of the Nrf2 pathway. Therefore, CAPE is a potential therapeutic drug for type Ⅱ diabetes. In this study, we initially extract the CAPE from the active components of propolis. Additionally, the type Ⅱ diabetes rat model was established with streptozotocin as well as the self-made high fat plus high sugar diet. Finally, the role of anti type Ⅱ diabetes was verified through detection of enzymes inhibitions.In the specific experiment, the combination of crushing technology and extraction of traditional Chinese medicine was applied for the first time. The crude propolis utilized in experiments were purchased from the South of Shaanxi and crushed before use. The extraction process of CAPE from propolis can be concluded as follows, taking a certain amount of propolis to across No.20 smash, adding 10 times the amount of chloroform-methanol (20:1) mixed solvent, after applying ultrasonic extraction at 60℃ and 70Hz, the extracts was centrifuged at 5000r/min for 10min, the supernatant was separated and added 2mol/L hydrochloric acid to adjust the solution to pH=3. Then the supernatant was subjected to vacuum concentration, continuously, distilled water were added to the concentrated extract before equal volume of petroleum ether were added to the extract for 4 times, the mixture were centrifuged for 10min under 5000r/min, the supernatant was concentrated under reduced pressure to afford the semi-finished product. After we got the semi-finished products,200-400 silica gel column chromatograph were used to further separate them, the raw products were purified by preparative liquid chromatograph to obtain pure is 80.6% product.To verify anti-diabete activity of CAPE, type Ⅱ diabetes rat model was established by feeding with high fat and high sugar diet (self-made, the main ingredients are lard, eggs, etc.), then streptozotocin (50mg/kg and 30 mg/kg) were injected continuously to damage islet B cells which resulting the anticipated model. Based on the detection of biochemical indexes in serum, we can restrainedly draw the preliminary conclusion that CAPE is effective for type Ⅱ diabetes. Further through the change of oxidation index and antioxidase, we found that the oxidation index of diabetic rats was higher than normal rats but conversely antioxidase was decreased. Therefore, under the present experimental conditions, caffeic acid phenethyl ester by scavenging free radicals and antioxidant effect, may have utility in the treatment of type Ⅱ diabetes. |
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