Effects of estrogens on the redox chemistry of iron: A possible mechanism of the antioxidant action of estrogens

Ruiz‐Larrea, M. Begoña; Leal, Ana M.; Martı́n, César; Martı́nez, Rosa; Lacort, Mercedes

doi:10.1016/0039-128x(95)00119-b

Cited by 68 publications

(36 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This trend occurs in spite of a study showing that antioxidant capacities of various estrogenic structures were found to be dependent upon the aqueous or lipophilic nature of the assay system [Ruiz-Larrea et al, 2000]. Ruiz-Larrea et al [1995] found that catechol estrogens and DES increased the rate of Fe(III) reduction in aqueous solutions, while bE2 and E1 did not affect this rate. If lipid peroxidation (LPO) is based on Fe (III), this corroborates with our findings in that DES was better able to decrease MDA formation compared to bE2 and E1: DES (6.7)obE2 (19.8)oE1 (80.8).…”

Section: Discussionmentioning

confidence: 67%

Neuroprotective effects of estratriene analogs: structure‐activity relationships and molecular optimization

Perez

Cai

Covey

et al. 2005

Drug Development Research

View full text Add to dashboard Cite

Estrogens are neuroprotectants against a variety of insults, both in vitro and in vivo. Many of these insults involve an oxidative stress component and estrogens are known antioxidants. We (Green et al. [1997b] J Steroid Biochem Mol Biol 63:229-235) and others (Behl et al. [1997] Mol Pharmacol 51:535-541; Moosmann and Behl [1999] Proc Natl Acad Sci USA 96:8867-8872) have determined that the phenolic nature of the A-ring of the estradiol molecule is essential for neuroprotection. We performed structure-activity relationship studies using a library of estratriene compounds in well-established in vitro models for neuroprotection. We tested over 70 compounds in HT-22 (murine hippocampal) cells for their ability to inhibit cell toxicity against glutamate and iodoacetic acid, at two doses for each insult, and determined EC 50 values to ascertain potency comparisons with 17b-estradiol (E2). We verified that a phenolic A ring was essential for neuroprotection in these models. We also observed that hydrophobicity and planarity affects the ability of estratrienes to protect cells from oxidative stress. This neuroprotection correlated with their ability to inhibit iron-induced lipid peroxidation in vitro. In contrast, the ability of these estratrienes to bind estrogen receptors was negatively correlated with their ability to protect cells from oxidative stress or inhibit lipid peroxidation. Drug Dev. Res. 66:78-92, 2006.

show abstract

Section: Discussionmentioning

confidence: 67%

Neuroprotective effects of estratriene analogs: structure‐activity relationships and molecular optimization

Perez

Cai

Covey

et al. 2005

Drug Development Research

View full text Add to dashboard Cite

show abstract

“…It was suggested that flavonoid compounds and phenolic acids with o-dihydroxyl groups might be exerting their protective effects through chelation of metal ions during the Fenton reaction, or by the altering iron redox chemistry. 40,41 A complex system of synergy effects and different symbiosis between certain substances (phenolic acids, flavonoids, tannins, terpenes, and many others) is also very important for antioxidative activity. The scavenging properties of antioxidant compounds (flavonoid and phenolic acids) are often associated with their ability to form stable radicals.…”

Section: Resultsmentioning

confidence: 99%

Free‐radical scavenging activity of wormwood (Artemisia absinthium L) extracts

et al. 2004

View full text Add to dashboard Cite

In an effort to discover new antioxidant natural compounds, wormwood (Artemisia absinthium L) an aromatic-bitter herb, was screened. The sequential extraction was realized with five solvents of different polarities (70% methanol, petroleum ether, chloroform, ethyl acetate, n-butanol). The antioxidative activity was tested by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and reactive hydroxyl radical during the Fenton reaction trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), using electron spin resonance (ESR) spectroscopy. Results demonstrated that the antiradical and antioxidative activity depend on the type and concentration of applied extracts and increased in the order ethyl acetate > methanol > n-butanol > chloroform > petroleum ether > remaining water extracts. The investigation showed that the antiradical activity increased with increasing concentration of all extracts. The high contents of total phenolic compounds (25.6 mg g −1 ) and total flavonoids (13.06 mg g −1 ) indicated that these compounds contribute to the antiradical and antioxidative activity. In a model system, the formation of o-semiquinone radicals from quercetin and chlorogenic acid was obtained to prove the mechanism (hydrogen donating and/or one-electron reduction) of free-radical scavenging activity.

show abstract

“…Significantly higher SA values for OH radical assay than for DPPH radicals for both types of GWM and CM extracts (p < 0:01) can be explained by the fact that some natural compounds are good iron chelators. It was suggested that flavonoid compounds (with o-diphenolic groups in the 3,4-dihydroxy position in ring B and the ketol structure, 4-oxo, 3-OH or 4-oxo, 5-OH in the C ring of the flavonols) and phenolic acids (with o-dihydroxyl groups) might be exerting their protective effects through chelation of metal ions in the course of the Fenton reaction, or by altering the iron redox chemistry (Morel, Lescoat, Cillard, & Cillard, 1994;Ruiz-Larrea, Leal, Martin, Martinez, & Lacort, 1995).…”

Section: Discussionmentioning

confidence: 99%