Study on extraction and purification of glycoprotein from Pinctada martensii' mucus and its antioxidant activity

In this study, we used direct alcohol precipitation, salt extraction and alcohol precipitation, water extraction and alcohol precipitation to extract the glycoprotein from Pinctada martensii' mucus, and the direct alcohol precipitation sample (DAS) was preferred. We obtained the direct alcohol precipitation and purification sample (DAPS) by Sephacryl S-200 and determined antioxidant activity of DAS and DAPS in vitro. The results show that DAS had the highest yields of sugar and protein, and there is no significant difference in the protein composition of the crude glycoproteins extracted by the three methods. The total sugar and protein contents of DAPS were (22.72±0.26)% and (71.18±0.62)%, respectively, and the molecular weight was mainly 245 kD. Both DAS and DAPS had certain antioxidant activity. The scavenging abilities of DAS and DAPS to hydroxyl radical were significant, and their scavenging rates to hydroxyl radical were higher than 90% at 0.8 mg·mL⁻¹. Both had scavenging activity to superoxide anion free radical and DPPH free radical. The results provide theoretical basis data for exploring the active components of P. martensii' mucus.