title: Capacity of reductants and chelators to prevent lipid oxidation catalyzed by fish hemoglobin.
abstract: The efficiency of different reductants (reduced glutathione, ascorbic acid, and catalase) and metal chelators [ethylenediaminetetraacetic acid (EDTA), citric acid, sodium tripolyphosphate (STPP), and adenosine-5'-triphosphate (ATP)] to inhibit lipid oxidation promoted by fish hemoglobin was investigated. The inhibitory activity on hemoglobin-catalyzed lipid oxidation was also evaluated for grape oligomeric catechins (proanthocyanidins), which have both reducing and chelating properties. The antioxidant activity was studied in two different lipid oxidation models, liposomes and washed minced fish muscle. Grape proanthocyanidins were found to be significantly more effective than other reductants to prevent hemoglobin-mediated lipid oxidation in both liposomes and washed fish muscle. Reduced glutathione was also efficient to retard lipid oxidation at the same molarity in washed fish muscle, whereas catalase and ascorbic acid showed a lower antioxidant activity. Metal chelators were less active than reductants, and consequently, the former were necessarily evaluated at much higher concentration than grape proanthocyanidins and reducing compounds. STPP was found to be the iron chelator with the strongest efficiency to delay hemoglobin-mediated lipid oxidation followed by EDTA. Citric acid and ATP were ineffective in retarding lipid oxidation in both systems. Grape proanthocyanidins provided the most extensive protection to preserve hemoglobin at ferrous state in washed fish muscle. Our results draw attention to the greater capacity of reducing compounds to prevent fish hemoglobin-mediated lipid oxidation in comparison with iron chelators, suggesting that the free radical scavenging and/or reduction of ferrylHb species are crucial actions to avoid the pro-oxidant capacity of fish hemoglobin.
authors.affiliation: Instituto de Investigaciones Marinas (CSIC), Eduardo Cabello 6, E-36208 Vigo, Spain.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Maestre
authors.forename: Manuel
authors.initials: M
authors.lastname: Pazos
authors.forename: Jacobo
authors.initials: J
authors.lastname: Iglesias
authors.forename: Isabel
authors.initials: I
authors.lastname: Medina
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology*; D005399:Fishes / Q000097:blood*; D005978:Glutathione / Q000494:pharmacology; D006454:Hemoglobins / Q000737:chemistry*; D015227:Lipid Peroxidation / Q000187:drug effects*; D009132:Muscles / Q000737:chemistry; D010084:Oxidation-Reduction; D044945:Proanthocyanidins / Q000494:pharmacology; D019163:Reducing Agents / Q000494:pharmacology*; D027843:Vitis / Q000737:chemistry
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D006454:Hemoglobins; D044945:Proanthocyanidins; D019163:Reducing Agents; D002374:Catalase; D005978:Glutathione; D001205:Ascorbic Acid