Carboxymethylated Derivative And Their Antioxidant Activities Of Polysaccharides From Auricularia Auricula

Auricularia auricula is a famous traditional Chinese Medicine and food fungus, which has immunity, hypoglycemic effect, antihyperlipidemia, antitumoural and antioxidant activities.The chemical-modification of the polysaccharides can enhance solubility and bioactivity of the polysaccharides.The carboxymethylated derivative of polysaccharides from Auricularia auricula was not reported. Therefore preparation of the carboxymethylated derivative of Auricularia auricula polysaccharides, isolation, purification,structure analysis and antioxidant activity were systematically studied. The main contents and results are as follows:1.To study the three factors including temperature, time and solid-liquid ratio on the yield of the polysaccharides from Auricularia auricular(AAP).The results show that temperature was the most important factor for the extraction percentage of the polysaccharides, and solid-liquid ratio was second. The optimal extraction technology conditions were that the temperature was 100℃,the extraction time was 4h, the solid-liquid ratio was 1:70, the extraction times were 2 times and pH was 7.0. The yield and content of AAP were 32.24% and 64.23%,respectively.2. To study the preparative and purify the carboxymethylated derivative of Auricularia auricula polysaccharides (CMAAP).The yield and degrees of substitution (DS) of CMAAP were 61.36% and 0.857;the solubility of AAP and CMAAP were 0.1 mg/mL and 0.6mg/mL.Purify CMAAP with DEAE-52 cellulose and sephadex G-100 column chromatography,obtated the five kinds of pure polysaccharides.3.To determine the molecular and the compose of monosaccharides by HPLC and GC.The molecular of CMAAP11,CMAAP22,CMAAP33,CMAAP44 and CMAAP55 were 3400948,3460190,3549768,3675360 and 3743691.The monosaccharides compose of CMAAP11,CMAAP44 and CMAAP55 are glucose; The monosaccharides compose of CMAAP22 and CMAAP33are mannose and glucose,molar ratio is1.06:1 and 2.95:1.4. To study the characteristics of each component by IR,NMR,periodate oxidation, Smith degration and so on. IR results showed that characteristic absorption peaks of the carboxymethyl be possessed with1600 cm-1 and 1420 cm-1,NMR showed that not only α-glucosidic bond configuration but alsoβ-glucosidic bond configuration were existed in each component; the type and proportion of he glucosidic bond configuration of each component were determined by by periodic acid oxidation and smith degradation; CMAAP11,CMAAP22,CMAAP33,CMAAP44 and CMAAP55 were be not proofed with triple helix stereo-configuration by he experiment of Congo red.5.To study the antioxidant activity of AAP,CMAAP,CMAAP22 and CMAAP33. Auricularia auricula polysaccharides and the carboxymethylated derivative of Auricularia auricula polysaccharides have of·OH、DPPH-and ABTS+.The sacvening capacity on·OH,the carboxymethylated derivative of Auricularia auricula polysaccharides are stronger than AAP, The sacvening capacity of CMAAP33,CMAAP22 and CMAAP are 56%,52.13% and 38.42%(AAP is 27.75%) in 2mg/mL;The sacvening capacity on DPPH,the carboxymethylated derivative of Auricularia auricula polysaccharides are stronger than AAP,close to Vc, The sacvening capacity of CMAAP33,CMAAP22 and CMAAP are 79.34%,78.95% and 63.03%(AAP is 46.38%)in 1.5mg/mL; The sacvening capacity on ABTS+,the carboxymethylated derivative of Auricularia auricula polysaccharides are stronger than AAP, The sacvening capacity of CMAAP33,CMAAP22 and CMAAP are 69.55%,65.53% and 55.88%(AAP is 38.30%) in 2mg/mL.