| Morchella esculenta, which belongs to Ascomycotina, Discomycetes, Pezizales,Morchellaceae, Morchella, is a nutritional and medicinal mushroom with refreshing fragrance. It contains many biological active materials, such as polysaccharides, protein, trace elements, dietary fiber and vitamins, etc. The polysaccharides from M. esculenta had the functions of antitumour, fatigue resistance, antivirus and immunoregulation.Selenium is an essential trace element of human being, and participates in synthesis of enzymes and protects the structure and function of biomembrane from overoxidation and damage. Se-deficiency can cause about 40 diseases animals. Selenium-polysaccharide (Se-polysaccharide) has the effects of selenium and polysaccharide. There are fewer reports about the organic combination of polysaccharide and selenium into seleno-polysaccharide.In this paper, the extraction conditions for M. esculenta exopolysaccharide (EPS) in submerged culture were optimized on the basis of the single-factor tests, Plackett–Burman (PB) design and response surface methodology (RSM). The in vitro and in vivo antioxiant activities of Se-polysaccharide and EPS were evaluated.1. Optimization EPS extractionThe optimum extraction conditions for EPS production were concentration temperature 84.07°C, precipitation time 22.19 h, and pH 8.44, while the production of EPS was predicted be 5.45 g/L. In view of the operating convenience, the optimal extraction parameters were determined to be concentration temperature 84°C, precipitation time 22 h and pH 8.4, and the predicted EPS production was 5.36 g/L, slightly lower than that of the maximum predicted value.2. Antioxidant activity of EPS in vitroResults showed that the EPS had significantly scavenging effects on superoxide anion, hydroxyl and DPPH radicals and reducing power. The EC50 values of EPS scavenging superoxide anion, hydroxyl and DPPH radicals were 111±4 mg/L, 103±4 mg/L, and 189±8 mg/L, respectively.3. Antioxidant activity of Se-MIP and Se-MIP-1 in vitroSe-MIP and Se-MIP-1 were two components of M. esculenta mycelia, and obtained by alcohol sedimenting and protein removing, respectively. The selenium contents of Se-MIP and Se-MIP-1 were 19.78μg/g and 12.11μg/g, repsectively. MIP and MIP-1 of M. esculenta mycelia were obtained according to the former method, using positive controls of antioxidant activity asssy in vitro.The Se-MIP and Se-MIP-1 had significantly scavenging effects on superoxide anion, hydroxyl, DPPH radical and reducing power. The EC50 values of Se-MIP scavenging superoxide anion, hydroxyl and DPPH radicals were 117±6 mg/L, 142±8 mg/L, and 131±4 mg/L, respectively, and the EC50 values of Se-MIP-1 were 132±7 mg/L, 201±8 mg/L, and 136±5 mg/L, respectively.4. Antioxidant activities of EPS in vivoThe effect of EPS on antioxidation capacity of mice was observed by measuring the superoxide dismutase activity, glutathione peroxidase activity, and the lipoperoxide content. The in vivo results showed that EPS could significantly elevate the activity of superoxide dismutase (SOD) and glutathione peroxidase activity (GSH-Px), and decrease the MDA content in mice blood.5. Antioxidant activities of Se-MIP and Se-MIP-1 in vivoThe in vivo antioxidant effects of Se-MIP and Se-MIP-1 on SOD and GSH-Px activity and MDA content in the blood, heart, liver, kidney, spleen of mice were investigate. Results showed that Se-MIP could remarkably increase the activity of SOD and GSH-Px, decrease the MDA content. Se-MIP-1could significantly decrease the MDA cntent, having no obvious influence on the activity of SOD and GSH-Px.The results suggest that the EPS and Se-polysaccharide of M. esculenta had significantly antioxidant activity in vivo and in vitro, which could be used as natural and potential antioxidants. |
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