| Bioconversion technology has been widely used in biological synthesis and structure modification, conversion of prodrug compounds, development of new drugs, drug metabolism studies, Many plant polysaccharides have been reported show strong biological activity by bioconversion, but the report about Trichoderma viride biotransform Auricularia auricular polysaccharides(AAP) is not yet reported. This experiment intended to use AAP as raw material, Trichoderma viride as the transformation of strains to investigate the structure and physiological activity that AAP derivative by bioconversion. In this article, we firstly screened the strains from four kinds of Trichoderma viride which is the strongest transforming strains, studied the optimal conversion process, then get different molecular weight fragments of AAP derivative through the membrane separation technology, and screened the best segments according to the vitro index, include regulating blood sugar level, blood lipid and antioxidant. After that we used infrared spectrum analysis, monosaccharide composition analysis method to study the composition and structure of the AAP derivative fragment. Finally we analyzed its possible mechanism. The main study contents are as follows:(1) Trichoderma viride TV2 strains was the strongest conversion strain as the transformed microorganism.The optimum process to prepare AAP derivative as follows: water content of 61.74%, inoculation amount of 12.36%, temperature of 31 ℃, time of 6 d, and under this condition the conversion rate was 26.89%.(2) The AAP derivative were classified to obtain fragments of different molecular sizes by membrane separation technology, the paper was studied in vitro hypoglycemic, Anti- hyperlipidemia and anti-oxidant activity. Comparison with AAP, the molecular weight of AAPD-6 has the highest of inhibitiving α- amylase activity, followed by the fragment of AAPD-5. The molecular weight of AAPD-3 has the highest of binding bili salt capability. The molecular weight of AAPD-6 has the highest of total reduction capability, followed by the fragment of AAPD-7 and AAPD-5. The molecular weight of AAPD-7 has the highest of hydroxyl radical scavenging capability, followed by the fragment of AAPD-6. The molecular weight of AAPD-6 and AAPD-7 has the highest of ABTS·+ radical scavenging activity, Comprehensive analysis of different molecular size of AAP derivative which is physiological activity, The molecular weight of AAPD-6 has the best activity which is hypoglycemic, Anti- hyperlipidemia, total reducing capab ility, ABTS·+ radical scavenging activity, in addition the hypoglycemic is best.(3) Using infrared spectrometry and gas chromatography- mass spectrometry analysis AAPD-6 which is biotransformed by Trichoderma viride. We have found that AAP is for pyran type, AAPD-6 is furan type. It is higher that the content of D-galactose, D- mannose, D- glucose in AAPD-6s monosaccharide composition, the contents of L-rhamnose,L-arabinose, D- xylose are low, and there were significant differences in the mole ratio of monosaccharides, the mole ratio of L- rhamnose, L-arabinose, D-xylose, D-fructose, D-galactose, D- mannose, D-glucose is 1.34:0.84: 0.90:2.52:4.99:2.17.(4)This study utilize the streptozotocin- induced diabetic mice fed AAPD-6s, analyzed the index of diet, antioxidant, blood sugar and lipid levels of diabetic mice, We found that AAPD-6 on diabetic mice had symptom-relieving effect, improved glucose tolerance, lowed fasting blood glucose level; AAPD-6 enhanced SOD and GSH-Px activities, antioxidant and lipid indexes have shown good effects in the experiment, it indicated that AAPD-6 may be improved antioxidant enzymes, reduced lipid peroxidation, lowed blood lipids to alleviate symptoms of diabetes in mice.In summary, compared with the AAP, AAPD-6 which was biotransformed by Trichoderma viride has better activitise, such as the higher hypoglycemic, lipid- lowering and antioxidant effect. It provided an experimental basis and technical reference for natural hypoglycemic development of new drugs and drug modified natural products. |
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