Study On Isolation, Purification, Physicochemical Properties And Anti-Fatigue Function Of Polysaccharides From Auriculria Auricula

Auricularia auricular (L.ex Hook.) Underw. is known to a kind of nutritious and officinal edible fungi in China. Polysaccharides, as one of main active components of A. auricular, have various functions such as modulating human immune system, reducing blood pressure and blood-fat, antitumor, improving the function of stomach, protecting liver, and so on.This paper used the fruit of A. auricular as rough material, studied on the extraction process, purification, physicochemical properties and anti-fatigue function of the polysaccharides from A. auricular by modern analysis technique. The main results are as follows.1. This paper optimized the extraction process of polysaccharides, which concluded the methods of traditional water extraction, microwave and ultrasound assisted extraction, and studied the effects of microwave and ultrasound wave on molecular weight distribution of the extracted polysaccharides. The yields of one time extraction are 18%-19%,28%-29% and 24%-25%, and those of two times are 22%-23%, 33%-34% and 30%-31%, respectively. The methods of microwave and ultrasound assisted extraction can increase the yields of polysaccharides remarkably, and accelerate the extraction of large molecular weight components, but had certain effects on the extraction of small molecular weight components of polysaccharides.2. Three main components were isolated and purified from the refined polysaccharides(AAP, processed by removing protein, removing pigment and dialysing) by DEAE Sephadex A-25 ion-exchange chromatography and Sephadex G-200 gel-filtration chromatography. They were named AAPⅠ-a, AAPⅡ-a and AAPⅢ-a respetively. The three components were shown to contain no protein and nucleic acid by UV-scanner and be homogeneous by gel-filtration chromatography and high performance liquid chromatography.3. AAPⅠ-a, AAPⅡ-a and AAPⅢ-a were primrose flocs. Analysed by gel permeation chromatography, the mean molecular weight (?) of them were 1.37×10~4Dal, 1.55×10~4Dal and 8.68×10~5Dal, and (?) were 1.26×10~4Dal, 1.27×10~4Dal and 4.12×10~4Dal, respectively. Analysed by high performance liquid chromatography, AAPⅠ-a was consisted of glucose. The monosaccharides of AAPⅡ-a and AAPⅢ-a were identified as xylose and glucose with rates of 1.33:1 and 1:2.28, respectively. The structrue of components were analysed by infra-red spectrometry, the results showd that AAPⅠ-a and AAPⅡ-a wereβ-pyranose and AAPⅢ-a was furanose.4. AAP and AAPⅢ-a could remarkably prolong the forced-swimming time of mice, increase the reservation and recovering rate of liver glycogen and musle glycogen, decrease the rising amount and accelerate the clearance speed rate of blood lactic acid after exercise in mice. AAPⅢ-a could remarkably decrease the rising amount and accelerate the clearance speed rate of blood urea nitrogen after exercise in mice. The effects of AAPⅢ-a were better than AAP, and AAP-Ⅲ-a 100 mg/(kg·bw·d) was best.