Extraction And Separation Of Pomegranate Seeds Polysaccharide And The Preliminary Development Of Hypoglycemic Beverage

The Punica granatum L,a species belonging to the family Punicaceae, deciduous shrubs or small trees, is mainly distributed in the temperate and subtropical regions. Pomegranate not only can be eaten directly, but its all parts including the pericarp, root-bark, pomegranate seed, leaves and flowers are widely used in Chinese herbal formula for many physiological functions of them. Pomegranate seed accounts for about 12% of the total weight, but most pomegranate seed resource can not give full play to its potential because of people’s failing to recognize the use value of them.Thus it’s necessary to promote our research work on the active ingredients and pharmacological effects of pomegranate seeds.In view of the past many kinds of plant polysaccharides having been founded with good effect on decreasing blood glucose and the previous research achievements, this subject used water to extract pomegranate seed polysaccharide and researched its hypoglycemic effect in vitro with its inhibition on the activity of a-glucosidase. Ultrafiltration and DEAE-52 cellulose column chromatography was used to isolate active components from pomegranate seeds polysaccharides which had an effect on decreasing blood glucose.At last, a hypoglycemic beverage was preliminarily developed using the water extract of pomegranate seed, then the influence on diabetic mice’s body weight and blood glucose level of this beverage was researched. The main results are as follows:(1)To determine the best extraction process of pomegranate seed polysaccharide. The best conditions of two methods including traditional hot water extraction and ultrasonic assisted extraction were determined through orthogonal experiment.For the traditional method, the polysaccharide yield was 26.51 mg/g under the best conditions: solid-liquid ratio of 1:30, temperature of 70℃ and time of 100 min. And for the ultrasonic assisted extraction, the yield was 26.58 mg/g under the conditions: solid-liquid ratio of 1:40, temperature of 50℃, time of 30 min and power of 250 W.(2)To separate and purify the crude polysaccharide. Proteins and pigments got removed by Sevage method and activated carbon. After Ultrafiltration, three components with different molecular level were separated, respectively named PSP-A、 PSP-B and PSP-C. Among them, PSP-C showed the best hypoglycemic effect in vitro with the a-glucosidase-inhibitory rate of 51.41%.Two components of PSP-C-1 and PSP-C-2 whose a-glucosidase-inhibitory rate were respectively 13.07% and 59.5% were purified by DEAE-52 cellulose column chromatography. UV scanningwithin 190 to 600 nm indicated that PSP-C-2 had a high purity without proteins and nucleic acids, because it didn’t have apparent absorption peak near the wavelength of 280nm and 260 nm.(3)To study the technical formula of hypoglycemic beverage.Water extract content of pomegranate seed was determiner by sensory score and a-glucosidase-inhibitory rate.Orthogonal experimental results showed the optimal formula of adding 0.05% citric acid,7% xylitol and 0.2% beta-cyclodextrin. The addition of 0.2% agar could optimize the stability of the beverage.In addition, the beverage coule not achieve a good hypoglycemic effect with a low pH value, so citric acid content should be controlled. The best way for beverage sterilization was determined at 100℃ for 10 minutes through the study of the influence of different conditions on hypoglycemic effect.(4)To verify the hypoglycemic effect of beverage in the body. The research indicated that hypoglycemic beverage could obviously reduce the weight and blood glucose level of diabetic mice and ease "three pliys and one little" symptom. But, it showed no obvious effect on the blood glucose in normal mice.