Study On Extraction Techniques,Structure And Biological Activity Of Bitter Melon Polysaccharides In Different Varieties (Lines)

Bitter melon (Momordica charantia) is one of the major vegetable crops which has remarkable medicinal value. In recent years, it was found that the fruit of Bitter melon contains large amounts of active ingredients, such as bitter melon polysaccharide,bitter melon saponin,Momordicin and so on. These active substances have lower blood pressure,blood fat, anti-tumor,anti-oxidation and other physiological functions.In this paper, five kinds of bitter melon materials (four varieties of bitter melon inbred lines and one market"cui fei") were grown in the field in the same environmental conditions in the first place, Then harvested tender bitter melon which was between (15-20) days, and to do quality (hardness, soluble solids, vitamin C content) test. On this basis, Furtherly to study the optimal extraction conditions of polysaccharide of bitter melon and compare the monosaccharide composition and basic structure of water-soluble polysaccharide with neutral polysaccharide of bitter melon. Finally, the neutral polysaccharide of bitter melon antioxidant activity (scavenging capacity and superoxide radical scavenging capacity) were measured. The main results are as follows:First, The optimal conditions of extracting bitter melon polysaccharide were at the temperature of 90℃, extracting time 3 h, the ratio of material to solvent 1:25, the ethanol concentration 95% and the extracting times 2.Second, there was different in monosaccharide composition between five kinds of water-soluble polysaccharides material of bitter melon, The crude polysaccharide was mainly composed of arabinose (Ara), mannose (Man), glucose (Glu) and galactose (Gal) and No.3,No.7 also had a little rhamnose (Rha) and xylose (XYL). Additionally, five kinds of neutral polysaccharide materials of bitter melon were mainly composed of glucose(Glu), only 7 inbred lines also contained a small amount of rhamnose(Rha).Third, In the infrared spectroscopy, water-soluble polysaccharide and neutral polysaccharides of bitter melon all had characteristic absorption peak of polysaccharide in the functional group area (4000-1300) cm-1 and the fingerprint area (<1300cm-1). bitter melon polysaccharide had a type andβtype pyran ring.Fourth, the polysaccharide of Bitter melon had scacenging ability on hydroxyl radicals (·OH) and superoxide anion radical (O2·), it had dose effect and also showed a linear relationship, The same material in a certain range of concentration, the higher the concentration, the higher clearance capability; there was different in clearance capability between different materials in the same concentration. when the concentration of polysaccharide solution was 1800 ug/ml, descending order of Scavenging hydroxyl radicals (·OH) was No.7>No.23>CuiFei>No.5>No.3; At different concentrations, Scavenging superoxide anion radical was consistent, all showed that No.23>No.3>CuiFei>No.7>No.5.In addition, the same material, scavenging ability of superoxide anion radical were higher than Scavenging ability of hydroxyl radicals (·OH). The significance analysis showed that there was significant difference between the material and the concentration on scavenging capacity of Superoxide radical; In the scavenging ability of hydroxyl radicals (·OH), there was significant difference only in concentration, and no significant difference between materials.