Estrogens are potentially the only steroids with an antioxidant role in pregnancy: in vitro evidence.
BACKGROUND
Pregnancy is a condition that favors oxidative stress by reactive oxygen species. Oxidative stress is involved in the etiopathogenesis of disorders of pregnancy such as pre-eclampsia. An antioxidant effect of estrogens has been described and a putative role of them as antioxidants has been proposed. The aim of this work was to evaluate in vitro the antioxidant properties of dehydroepiandrosterone sulfate, estradiol, estriol, progesterone, and testosterone, five steroid hormones present in the maternofetal circulation.


METHODS
The antioxidant properties of the hormones were evaluated by two methods: 1. their antioxidant effect on the auto-oxidation of linoleic acid, a hydrogen atom transfer reaction; 2. diphenylpicrylhydrazyl-scavenging capacity, a single electron transfer reaction.


RESULTS
Of the five hormones tested, only estradiol and estriol at 10 microM concentration exerted a strong antioxidant effect of 81.73 and 70.97% respectively on linoleic acid auto-oxidation, at the end-point of the reaction. Likewise, only these two hormones showed radical-scavenging activity on diphenylpicrylhydrazyl, noticeable only at supraphysiological concentrations of 1 mM.


CONCLUSIONS
Estradiol and estriol could play a role as antioxidants for maternofetal autoprotection in addition to their hormonal activity, but this role could be preferentially exerted by estriol due to its higher concentrations exhibited during pregnancy. In vivo studies are necessary to shed light on this issue.
Reyes
Miguel R
MR
Food and Nutrition Research Center, Durango, Dgo. México, Mexico. mareyes@ujed.mx
Sifuentes-Alvarez
Antonio
A
Lazalde
Brissia
B
D000328:Adult; D000975:Antioxidants / Q000378:metabolism* / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000378:metabolism; D019314:Dehydroepiandrosterone Sulfate / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000378:metabolism / Q000494:pharmacology; D004964:Estriol / Q000378:metabolism / Q000494:pharmacology; D004967:Estrogens / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006834:Hydrazines / Q000378:metabolism; D066298:In Vitro Techniques; D019787:Linoleic Acid / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000187:drug effects*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010851:Picrates; D011247:Pregnancy / Q000097:blood*; D011374:Progesterone / Q000378:metabolism / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013739:Testosterone / Q000378:metabolism / Q000494:pharmacology
D000975:Antioxidants; D001713:Biphenyl Compounds; D004967:Estrogens; D006834:Hydrazines; D010851:Picrates; D017382:Reactive Oxygen Species; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate; D019787:Linoleic Acid; C004931:1,1-diphenyl-2-picrylhydrazyl; D004964:Estriol