Isolation And Structure Analysis Of The Active Polysaccharides From Barley Malt

Barley, also named Hordeum vulgare L, is the fruit of a graminaceous annual herb. Themalt is made from malted barley that has been dried. Barley malt has been used as healthyfood and herbal ingredients in traditional Chinese medicine. Modern medical research resultshave proved that it has multiple bioactivities, such as hypoglycemic effect, hypolipemic effect,antioxidation activity.This paper investigated the active polysaccharides from barley malt. The results were asfollows:1. Alloxan-induced diabetic mice model was built, in which the hypoglycemic effect ofbarley malt water extract,30%ethanol extract,70%ethanol extract and ethyl acetate extractwas determined. The water extract from barley malt can decrease fasting plasma glucose ofthe diabetes mice. Further isolation of the water extract and activity detection, thepolysaccharides from barley malt can decrease fasting plasma glucose of the diabetes mice.2. With the single factor experiment, the optimal extracting conditions were obtained asfollows: the extracting temperature40℃, the extracting time3h, the extracting number3times, the ratio of water to material8:1, and the polysaccharide yield was8.90‰.3. Neutral polysaccharides（NBP）and acidic polysaccharides was isolated byDEAE-cellulose. BP I and BP II were further isolated from NBP by HW-55F and SephacrylS-400. BP I and BP II were pure determined by HPGPC and Gel filtration chromatography.BP I, a white powder, not sweet, non-volatile, is soluble in water, but insoluble inabsolute alcohol, aether and acetone. And the test of phenol-sulfuric acid method provedpositive, the test of iod starch reaction and staining of coomassie brilliant blue G250provednegative.BP II, a white powder with brown, not sweet, non-volatile, is soluble in water, butinsoluble in absolute alcohol, aether and acetone. And the test of phenol-sulfuric acid methodproved positive, the test of iod starch reaction and staining of coomassie brilliant blue G250proved negative.4. From HPGPC analysis, the molecular weight of BP I and BP II were about1.33×10⁴and1.04×10⁴, respectively. From GC analysis, BP I and BP II were homopolysaccharide.Retention time of hydrolysis products of BP I was different to standard monosaccharides,. BPII was composed of galactose. The structure was investigated by¹H-NMR、¹³C-NMR、135DEPT-NMR analysis.BP I consists only of glucofuranose units joined by1�'3bond, and both of α and βconfigureation appear alternately. The main chain of BP II is galactoses linked by1�'4bond, and the galactose, forminglateral chain, is linked to C-6of the galactose in the main chain.