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Pleurotus citrinopileatus Sing., also called golden oyster mushroom, belongs toEumycophyta, Basidiomycotina, Hymenomycetes, Agaricales, Pleurotaceae, Pleurotus. It notonly riches in nutrition and high economic values but also contains many biological activematerials, such as carbohydrates, protein, trace elements, enzymes, dietary fiber and vitamins,etc. Polysaccharides from fruiting bodies or culture broths of P. citrinopileatus have thefunction of antioxidation, antitumour, reducing blood press, immunoregulation, fatigueresistance and antimicrobe.In this paper, the extraction conditions of P. citrinopileatus SM-01exopolysaccharide(EPS) and intrecellular polysaccharide (IPS) in submerged culture were optimized on thebasis of Plackett-Burman (PB) design and response surface methodology (RSM). The in vitroand in vivo antioxidant activities of EPS and IPS were evaluated.（1） The optimal conditions of EPS extractionThe maximum EPS extraction reached4464.79mg/L, while the optimal conditions wereconcentration temperature70°C, concentration multiple3, precipitation time18, precipitationtemperature8°C, ethanol multiple3, ethanol concentration80%, pH7, extraction temperature70°C and extraction time2h. ANOVA results show that precipitation time, concentrationmultiple and pH had a highly significant influence on EPS extraction. RSM result shows thatthe optimal values of the variables affecting EPS extraction were precipitation time14.32h,concentration multiple2.13, pH7.44. Under these optimal conditions, the model gave themaximum predicted values of EPS extraction (5643.96mg/L). In view of the operatingconvenience, the optimal extraction parameters were determined to be precipitation time15h,pH8and concentration multiple2, while the predicted value of EPS extraction was5481.69mg/L, in accordance with the actual value (5479.75mg/L).（2） The optimal conditions of IPS extractionThe optimal conditions of IPS extraction were water multiple20, pH9, ultrasonic power400W, ultrasonic treatment time800s, extraction temperature90°C, extraction time1h,ethanol concentration90%, ethanol multiple4, precipitation time12h and precipitationtemperature-4°C, while the maximum yield of IPS reached11.71%. Precipitation time,ultrasonic treatment time and pH had a highly significant influence on IPS extraction. RSM result shows that the optimal values were precipitation time23.03h, ultrasonic treatmenttime664.09s and pH7.36. Under these optimal conditions, the maximum predicted values ofIPS extraction (16.13%). In view of the operating convenience, the optimal extractionparameters were determined to be precipitation time23h, ultrasonic treatment time660s andpH7.5, while the predicted value of IPS exrraction rate was16.11%, in accordance withactual the value (16.08%).（3） The in vitro antioxidant of EPSThe in vitro inhibition effects of EPS at a dosage of5g/L on superoxide anion, hydroxyl，and1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were53.10%,79.90%,69.07%,respectively, which were4.71%,44.64%,22.73%higher than that of butylatedhydroxytoluene (BHT), respectively. The reducing power of EPS was0.787, which was0.257higher than that of BHT. The in vitro results showed that EPS had strong scavenging effectson superoxide anion, hydroxyl and DPPH radicals and reducing power.（4） The in vitro antioxidant of IPSThe in vitro inhibition effects of IPS at a dosage of5g/L on superoxide anion, hydroxyland DPPH radicals were73.96%,69.2%, and50.75%, respectively, which were72.56%,22.83%and43.93%higher than that of BHT, respectively. The reducing power of IPS was0.9,69.81%higher than that of BHT. The in vitro results showed that EPS had strong scavengingeffects on superoxide anion, hydroxyl, DPPH radicals and reducing power.（5） The in vivo antioxidant of EPSThe activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), alanineaminotransferase (ALT), catalase (CAT), malondialdehyde (MDA) in blood, heart, liver,spleen and kidney of mice were investigated. The activities of GSH-Px, SOD, ALT and CATin mice blood were224.69U/mL,421.98U/mL,30.07U/mL,69.52U/mL, respectively, and theMDA level was8.47nmol/mL. The in vivo results showed that EPS had strong antioxidantactivity.（6） The in vivo antioxidant of IPSThe activities of GSH-Px, SOD, CAT and ALT in mice blood were241.38U/mL,454.95U/mL,60.32U/mL,32.39U/mL, respectively, and the MDA level was9.54nmol/mL. IPS cansignificantly improve GSH-Px, SOD, CAT, ALT activities, and reduce MDA content. IPS hadstrong in vivo antioxidant activity.
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