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Titolo:
TAMOXIFEN AND HYDROXYTAMOXIFEN AS INTRAMEMBRANOUS INHIBITORS OF LIPID-PEROXIDATION - EVIDENCE FOR PEROXYL RADICAL SCAVENGING ACTIVITY
Autore:
CUSTODIO JBA; DINIS TCP; ALMEIDA LM; MADEIRA VMC;
Indirizzi:
UNIV COIMBRA,FAC FARM,BIOQUIM LAB,COURACA APOSTOLOS,51 R-C P-3000 COIMBRA PORTUGAL UNIV COIMBRA,CTR NEUROCIENCIAS P-3049 COIMBRA PORTUGAL
Titolo Testata:
Biochemical pharmacology
fascicolo: 11, volume: 47, anno: 1994,
pagine: 1989 - 1998
SICI:
0006-2952(1994)47:11<1989:TAHAII>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOW-DENSITY LIPOPROTEINS; CIS-PARINARIC ACID; BREAST-CANCER; VITAMIN-E; SARCOPLASMIC-RETICULUM; CHROMANOXYL RADICALS; OXIDATIVE STRESS; ANTIOXIDANT; MEMBRANE; RAT;
Keywords:
TAMOXIFEN; 4-HYDROXYTAMOXIFEN; ANTICANCER DRUGS; BREAST CANCER; SARCOPLASMIC RETICULUM; LIPID PREOXIDATION; ANTIOXIDANTS; SCAVENGERS; PEROXYL RADICALS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
50
Recensione:
Indirizzi per estratti:
Citazione:
J.B.A. Custodio et al., "TAMOXIFEN AND HYDROXYTAMOXIFEN AS INTRAMEMBRANOUS INHIBITORS OF LIPID-PEROXIDATION - EVIDENCE FOR PEROXYL RADICAL SCAVENGING ACTIVITY", Biochemical pharmacology, 47(11), 1994, pp. 1989-1998

Abstract

Tamoxifen (TAM) is the antiestrogen most widely used in the chemotherapy and chemoprevention of breast cancer. It has been reported that TAM and its more active metabolite 4-hydroxytamoxifen (OHTAM) induce multiple cellular effects, including antioxidant actions. Here sarcoplasmic reticulum membranes (SR) were used as a simple model of oxidation to clarify the antioxidant action type and mechanisms of these anticancer drugs on lipid peroxidation induced by Fe2+/ascorbate and peroxyl radicals generated by the water-soluble 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) and by the lipid-soluble 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). Peroxidation was monitored by different assay systems, namely cis-parinaric acid (PnA) fluorescence quenching, production of thiobarbituric acid-reactive substances, polyunsaturated fattyacids (PUFA) degradation and oxygen consumption. TAM and OHTAM are efficient inhibitors of lipid peroxidation induced by Fe2+/ascorbate andstrong intramembraneous scavengers of peroxyl radicals generated either in the water or lipid phases by AAPH and AMVN, respectively. However, these drugs are not typical chain-breaking antioxidant compounds ascompared with vitamin E. Additionally, their antioxidant effectiveness enhances the protective capacity of vitamin E against lipid peroxidation induced by AMVN. OHTAM is a more powerful intramembraneous inhibitor of lipid peroxidation as compared with TAM; this effectiveness notcorrelating with alterations on membrane fluidity may be due to the presence of a hydrogen-donating HO-group in the OHTAM molecule and its preferential location in the outer bilayer regions where it can donatethe hydrogen atom to quench free radicals capable of initiating the membrane oxidative degradation. The stronger OHTAM intramembraneous scavenger capacity over TAM also correlates with its higher partition in biomembranes. Therefore, the strong peroxyl radical scavenger activityof OHTAM in the hydrophobic membrane phase may putatively contribute to the mechanisms of cytostatic and chemopreventive action of its promoter TAM on development of breast cancer.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/07/20 alle ore 16:59:05