Study On The Antioxidant Activities Of Oyster Water Extracts

Oyster (Ostrea talienwhanensis Crosse) is a prosperous resource of natural antioxidantcontaining many active substances. Water extracts of full oyster (FO), visceral mass (VM) andmantle cavity (MC) were prepared at low-temperature and the compositions in FO, peptideand amino acid (PAA), superoxide dismutase (SOD) and metallothionein (MT) wereseparated. The antioxidant activities of these samples were studied in reducing power assay,DPPH assay, Feton assay, pyrogallol autoxidation assay and liposome oxidation assay. Theantioxidant activities of the extracts were synthetically evaluated.The results indicated that in reducing power assay, FO, VM and MC had similar power,which of FO was weaker than that of ascorbic acid. The power of compositions in FOincreased with the same diluted fold in following the order: FO＞PAA＞MT＞SOD. InDPPH assay, FO, VM and MC had similar scavenging capacity, which of FO was greater thanthat ofα-tocophenol. The scavenging capacity of compositions in FO increased with the samediluted fold in following the order: FO＞PAA＞MT and SOD, among them MT and SOD hadno scavenging effect on DPPH radical. In Feton assay, the scavenging capacity of oysterwater extracts increased in following the order: VM>FO>MC, and the capacity of FO wasweaker than that of thiourea. The scavenging capacity of compositions in FO increased withthe same diluted fold in following the order: FO＞PAA＞MT＞SOD, among them SOD hadno scavenging effect on hydroxyl radical. In pyrogallol autoxidation assay, the scavengingcapacity of oyster water extracts increased in following the order: MC＞FO＞VM, and thecapacity of FO was greatly weaker than that of standard Cu/Zn-SOD. The scavengingcapacity of compositions in FO increased with the same diluted fold in following the order:FO＞SOD＞PAA＞MT. In liposome oxidation assay, the antioxidant activity of oyster waterextracts increased in following the order: FO＞MC＞VM, and VM exhibited slightprooxidant effects. The antioxidant activity of compositions in FO increased with the samediluted fold in following the order: SOD＞MT＞PAA＞FO.The scavenging capacity of oyster water extracts on the different free radicals increased inthe following order O₂^-·＞·OH＞DPPH·. The remarkable scavenging activities on O₂^-·may be concerned with the reducing power. Oyster water extracts had weaker antioxidant activitiesin egg lecithin oxidation system than radical system. Oyster water extracts were goodantioxidants, and their antioxidant activities were attributed to the interaction ofmulticomponent. Furthermore, it was reconfirmed that the antioxidant activities wereconnected with the experiment system of evaluation.