Effects of soy germ isoflavones and hormone therapy on nitric oxide derivatives, low-density lipoprotein oxidation, and vascular reactivity in hypercholesterolemic postmenopausal women.
OBJECTIVE
To evaluate the effects of soy germ isoflavones and hormone therapy on vascular reactivity, the formation of nitric oxide derivatives, and lipid peroxidation in hypercholesterolemic postmenopausal women.


METHODS
Women were treated with soy germ, 17beta-estradiol or 17beta-estradiol + noretisterone acetate for 3 months after taking placebo for 1 month. The plasma concentrations of nitrite + nitrate and S-nitrosothiols were evaluated by gaseous phase chemiluminescence; nitrotyrosine, electronegative low-density lipoprotein, and estradiol levels were determined by enzyme-linked immunosorbent assay; cholesterol oxides and isoflavones were determined by gas chromatography and high-performance liquid chromatography, respectively. Vascular reactivity was analyzed by high-resolution ultrasonography.


RESULTS
Soy germ isoflavones and hormone therapy induced a decrease in nitrite + nitrate, electronegative low-density lipoprotein, and cholesterol oxides, as well as an increase in S-nitrosothiols. Soy germ isoflavones lowered electronegative low-density lipoprotein, and cholesterol oxides more efficiently than did hormone therapy. Only soy isoflavones inhibited nitrotyrosine formation. A significant improvement of vascular reactivity was only seen in women treated with 17beta-estradiol.


CONCLUSIONS
The soy germ isoflavones and 17beta-estradiol, alone or associated with noretisterone acetate, in the doses and forms used here, have similar effects on the bioavailability of nitric oxide. Soy germ treatment inhibited lipid peroxidation more effectively than hormone therapy.
Pereira
Isabela R O
IR
School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
Faludi
André Arpad
AA
Aldrighi
José Mendes
JM
Bertolami
Marcelo Chiara
MC
Saleh
Mohamed H
MH
Silva
Renata Alves
RA
Nakamura
Yara
Y
Campos
Maria Fernanda
MF
Novaes
Nadjara
N
Abdalla
Dulcineia Saes Parra
DS
D000368:Aged; D002784:Cholesterol / Q000097:blood; D004958:Estradiol / Q000097:blood; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D006973:Hypertension; D007529:Isoflavones / Q000097:blood / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects*; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D017698:Postmenopause; D045730:Soy Foods; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation / Q000187:drug effects*
D007529:Isoflavones; D014280:Triglycerides; D009569:Nitric Oxide; D004958:Estradiol; D002784:Cholesterol