Antioxidant action of the antihypertensive drug, carvedilol, against lipid peroxidation.
The action of carvedilol, a vasodilating, beta-adrenoceptor blocking agent, against lipid peroxidation has been the subject of many studies, but the results reported thus far are contradictory. In an attempt to define the antioxidant mechanism of carvedilol against lipid peroxidation, the dynamics of the action of carvedilol were studied in several oxidation systems. We investigated the reactivity of carvedilol toward radicals and its inhibitory effect on lipid peroxidation induced by several kinds of initiating species such as azo compounds and metal ions in solution, micelles, membranes, and low-density lipoprotein. Carvedilol exerted poor reactivity toward phenoxyl, alkoxyl, and peroxyl radicals in acetonitrile solution nor did it show an appreciable antioxidant effect against either the peroxyl radical-induced oxidation of methyl linoleate in acetonitrile or against phosphatidylcholine liposomal membranes in aqueous suspension. Carvedilol completely inhibited the ferric ion-induced oxidation of methyl linoleate micelles by sequestering ferric ions, but not by reducing hydroperoxide. It was shown that carvedilol enhanced the oxidation of micelles induced by either methemoglobin or peroxyl radical. Carvedilol, which was added exogenously, did not suppress the oxidation of isolated low-density lipoprotein induced by peroxyl radical or cupric ion. These results show that carvedilol does not act as a radical-scavenging antioxidant, but that it does act most efficiently as an antioxidant against ferric ion-induced oxidation by sequestering ferric ion.
Noguchi
N
N
Research Center for Advanced Science and Technology, University of Tokyo, Meguro, Tokyo, Japan. nonoriko@oxygen.rcast.u-tokyo.ac.jp
Nishino
K
K
Niki
E
E
D000959:Antihypertensive Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D002227:Carbazoles / Q000494:pharmacology*; D000077261:Carvedilol; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008041:Linoleic Acids / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008077:Lipoproteins, LDL / Q000187:drug effects / Q000378:metabolism; D008081:Liposomes; D008823:Micelles; D010084:Oxidation-Reduction / Q000187:drug effects; D011412:Propanolamines / Q000494:pharmacology*; D012996:Solutions; D013025:Glycine max / Q000737:chemistry; D013997:Time Factors
D000959:Antihypertensive Agents; D000975:Antioxidants; D002227:Carbazoles; D005609:Free Radicals; D008041:Linoleic Acids; D008077:Lipoproteins, LDL; D008081:Liposomes; D008823:Micelles; D011412:Propanolamines; D012996:Solutions; D000077261:Carvedilol; C005575:methyl linoleate