Study On Extraction And Cholesterol Removal From The Ovum Oil Of Rana Chensinensis And Its Hypolipidemic Activity

The current research was financially supported by the Project of Technology Transformation in Jilin Province(20130727074YY).Ovum oil of Rana chensinensis(OORC)is a traditional Chinese food,which has nutritional and medicinal values.OORC has a broad market prospect for its ability of improving blood lipids,resisting anxiety,enhancing endocrine system,protecting fromovarian and liver damage,tranquilizing the central nervous system and counteracting convulsion.In the current study,OORC was extracted by ultrasonic method and microwave method,with two methods compared.Cholesterol was removed by silica gel adsorption,activated carbon adsorption,beta-cyclodextrin(?-CD)encapsulation,co-precipitation with ?-CD and crosslinked ?-CD.Unsaturated fatty acid profiles of OORC prepared with different methods of cholesterol removal were determined and compared using gas chromatography-mass spectrometry.OORC effect on lipoid metabolism was further evaluated in a rat model.The main findings are as follows:(1)Microwave assisted extraction of OORC was better than ultrasonic method in extraction yield and cost.The optimized microwave extraction conditions were: soak time was 3.33 h,material/liquid ratio was 1:9.82(g/m L),the microwave power was 600 W and the microwave time was 30 min.Under the above condition,the ovum oil of Rana chensinensis extraction efficiency reached(20±0.67)%.OORC obtained thereby was yellow,clear and impure.(2)We evaluated the effect of silica gel adsorption,activated carbon adsorption,?-CD encapsulation,co-precipitation with ?-CD and crosslinked ?-CD on cholesterol removal of the OORC.Co-precipitation with ?-CD showed the highest cholesterol reduction rate.Cholesterol removal rate with OORC increased after decreases with liquid content??-CD concentration and reaction temperature.Heating time to remove cholesterol had no significant effect(P>0.05).We further obtained the optimized processing conditions for cholesterol removal from OORC using co-precipitation with ?-CD(OORC to ethanol solution ratio was 1:3(g/m L),?-CD concentration was 30%,mixing time was 3 h and the temperature was 40?,under which cholesterol removal rate reached as high as 76%.Cholesterol removal had no change on unsaturated fatty acid content but increased the content of linolenic acid,arachidonic acid,DHA,docosapentenoic acid relative.The relative content of monounsaturated fatty acids increased from 4.96% to 29.12%,while the saturated fatty acids decreased from 36.49% to 19.48%.(3)The hyperlipidemic rats was fed OORC and phytosterol.The results showed that the phytosterol group?OORC group,and OORC-phytosterol group significantly reduced the total triglycerides(P < 0.05)and low density cholesterol but increased high density cholesterol level in rats.The higher dose of OORC-phytosterol,the lower the low density cholesterol level.The effect of OORC was the closest to high dose OORC-phytosterol group.Therefore,OORC and OORC-phytosterol combination has good effect to prevent hyperglycemia.The OORC was shown to be better than OORC-phytosterol combination in blood lipid lowering.