摘要：

The total antioxidant activity in the muscle, liver and intestine of elevenspecies of Malaysian freshwater fish known as Pangasius polyuranodon,Anabas testudineus, Channa striatus, Clarias batrachus, Labeo rohita,Tilapia mossambica, Leptobarbus hoevenii, Trichogaster pectoralis,Hemibagrus nemurus, Cyprinus carpio carpio and Puntius gonionotus wereevaluated using the optimized thiobarbituric acid (TBA) method. Thesynthetic antioxidant, butylated hydroxytoluene (BHT) was used as positivecontrol. The peroxidation of linoleic acid in the thiobarbituric acid system wasmarkedly inhibited by all the sample extracts compared with the control assayand also showed very low chelating activity with the iron chelator test. Thisindicated that the tissue samples contained insignificant quantities of ironchelators which would otherwise interfere with the TBA method. All the fishextracts exhibited total antioxidant activity in the order of muscle (61-81%) >liver (51-83%) > intestine (40-70%).Three fish species identified to have high antioxidant activities in the muscletissue namely Anabas testudineus, Clarias batrachus and Labeo rohita and aiiispecies with the lowest antioxidant activity, Hemibagrus nemurus wereselected for determination of the lipophilic antioxidants using the HighPerformance Liquid Chromatography (HPLC) analysis. The high antioxidantactivities found in the muscle of Anabas testudineus and Labeo rohita wereinfluenced by the presence of relatively high amounts of lipophilicantioxidants namely a-, P-, y-, 6- tocopherols, retinol and coenzyme Qlo.Liver, which was found to have retinol at 0.71 1 + 0.09 to 6.05 + 0.16 pg/g wetweight probably influenced the antioxidant activities obtained. However, theintestine showed the lowest antioxidant activity compared to the other tissuesexamined. It was found that P-tocopherol (1.31 6 -3.861 pg/g wet weight) wasthe only lipophilic antioxidant present.The distributions of the various tocopherol homologues, retinol andcoenzyme Q homologues in different tissues of Malaysian freshwater fishindicated that these compounds might be independently regulated in eachtissue. The difference in the antioxidant activities in the muscle, liver andintestine of different samples in this study may be influenced by the presenceof different types of lipophilic antioxidants in each sample. The three potentialMalaysian freshwater fish species with high antioxidant activities identifiedwere Anabas testudineus, Clarias batrachus and Labeo rohita.In conclusion, the Malaysian freshwater fish species examined which werefound to have high antioxidant activities are recommended as part of the dietas they may be able to protect the human body from free radicals and retardthe progress of many chronic diseases. The fish extracts found to havelipophilic antioxidants in this study also can be used as accessible source of-&;MN WfAN A W Lm n p u 7 M~A UYSUnatural antioxidants to replace synthetic antioxidants, as possible foodsupplement as well as in pharmaceutical applications.

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