[Estimating ability of dihydroquercetin to inhibit oxidation of fibrinogen by ozone].

The ability of dihydroquercetin to inhibit the oxidation of fibrinogen has been evaluated. It is established that dihydroquercetin inhibits oxidation of fibrinogen by ozone, thus preventing oxidative modification of fibrinogen and preserving its functional activity.

[Antihypertensive and neuroprotective activity of quercetin and its derivatives].

Data available in the literature on the pharmacological activity of quercetin and its derivatives, which possess various biological properties including antihypertensive and neurotropic activity, are reviewed. The mechanisms of these effects and results of clinical trials are considered and prospects for the clinical use of quercetin and its derivatives are discussed.

[Antiproliferative and antioxidant activity of new dihydroquercetin derivatives].

Effect of nine new derivatives of dihydroquercetin (taxifolin) on the viability of cultivated normal and tumor cells, their antioxidant activity, and interconnection of the antioxidant activity with the chemical structure have been studied. Among these dihydroquercetin derivatives, the maximum antiproliferative activity on the model of rat fibroblast culture exhibited KN-2, KN-4, KN-7, and KN-8 compounds, while KN-7 and KN-8 compounds also showed maximum activity on the model of MCF-7 tumor cell culture (human breast cancer). The maximum general antioxidant activity was observed for the native dihydroquercetin and KN-8 compound. There is a strong correlation (with a correlation coefficient of 0.93) between the antiproliferative effects of dihydroquercetin derivatives on murine skin fibroblasts and MCF-7 cells (human breast cancer).

[Antiaggregant and antioxidant activity of estradiol and tamoxifen]. / Antiagrregatsionnye i antioksidantnye svoistva éstradiola i tamoksifena.

Tamoxifen did not influence the human platelet aggregation in vitro, while estradiol at a concentration of 10(-6) M inhibited the aggregation of human thrombocytes induced by ADP, serotonin + adrenaline, and adrenaline (epinephrine) by 14.7, 12.5, and 16.6%, respectively. Estradiol introduced in the range of effective concentrations from 10(-8) to 10(-4) M inhibited lipid peroxidation, while tamoxifen produced this effect only at a concentration of 10(-4) M. There was a correlation between the antiaggregant activity and antioxidant properties of estradiol.

[Anti-arrhythmia activity of estradiol valerate and estradiol nitrate]. / Issledovanie antiaritmicheskikh svoistv éstradiola valerata i nitrata éstradiola.

Estradiol valerate and estradiol nitrate exhibit significant antiarrhythmic activity of on the aconitine arrhythmia model in rats. In both cases, the maximum effect was observed in a dose of 0.5 mg/kg.

[Comparative evaluation of the antiradical and antioxidant activity of estrogens and their nitro derivatives]. / Sravnitel'naia otsenka antiradikal'noi i antioksidantnoi aktivnosti éstrogenov i ikh nitroproizvodnykh.

Estradiol, ethynylestradiol, and estradiol acetate possess antiradical activity (K7 = (1.8-2.0) x 10(-4) liter/mole sec). Nistranol exhibits antiradical properties only upon acid hydrolysis. The results of experiments with egg yolk liposomes showed evidence of a pronounced antioxidant activity of estradiol, ethynylestradiol, and estradiol nitrate, and the absence of such activity in nistranol. In the experiments on rat heart homogenates, nitroestrogens in a concentration of about 10(-4) M reduced the level of TBA-active products.

[Oxidative destruction of estradiol after treatment with hydrogen peroxide catalyzed by horseradish peroxidase and methemoglobin]. / Okislitel'naia destruktsiia éstradiola pod deistviem perekisi vodoroda, kataliziruemaia peroksidazoi khrena i metgemoglobinom.

It is shown that estradiol in the presence of horse radish peroxidase interacts with hydrogen peroxide, which is evidenced by an increase in its optical density at 280 nm. The photometering of samples containing estradiol and horse radish peroxidase upon their titration with hydrogen peroxide indicated that the increase in optical density stops after introducing hydrogen peroxide equimolar in concentration to estradiol. The stoichiometric ratio of estradiol consumed during oxidative destruction to hydrogen peroxide was 1:1. In the presence of ascorbate, the oxidative destruction of estradiol by the action of hydrogen peroxide, catalyzed by horse radish peroxidase, was observed only after a latent period and showed the same regularities as in the absence of ascorbate. It was found by calorimetry that, during the latent period, estradiol catalyzes the degradation of hydrogen peroxide and ascorbate without undergoing oxidative destruction. The substrates of the peroxidase reaction benzidine, 1-naphthol, and phenol interact with hydrogen peroxide in the presence of ascorbate and horse radish peroxidase in a similar way. Presumably, upon interaction with hydrogen peroxide in the presence of horse radish peroxidase, estradiol, like other substrates of this reaction, undergoes oxidative destruction by the mechanism of peroxidase reaction. It is shown that oxidative destruction of estradiol by the action of hydrogen peroxide can also be catalyzed by methemoglobin by the same mechanism. These data are important for understanding the role of estradiol in the organism and the pathways of its metabolic conversions.

[The protective effect of 17 beta-estradiol in experimental myocardial infarct]. / Zashchitnyi éffekt 17 beta-éstradiola pri éksperimental'nom infarkte miokarda.

The effect of 17 beta-estradiol on the regions of ischemia and necrosis in experimental myocardial infarction was studied in the experiments on rats. The ability of the hormone to decrease the damaged area due to anti-ischemic and antinecrotic effects is found.

[Effect of induction of enzymes of the cytochrome p-450 system on the survival of rats after acute hemorrhage]. / Vliianie induktsii fermentov sistemy tsitokhroma P-450 na vyzhivaemost' krys pri ostroi krovopotere.

The effect of acute hemorrhage on the functional status of microsomal cytochrome P-450-dependent hepatic monoxygenases and the impact of induction of these monoxygenases on the survival of posthemorrhagic male Wistar rats. Acute blood loss of the rats, which caused 50% deaths led approximately to a double decrease in the hepatic activity of 77-ethoxycoumarin-O-deethylase (ECOD). Induction of hepatic monoxygenases by phenobarbital in a dose of 80 mg/kg for 3 days, which caused a 2.4-fold increase in the activity of ECOD as compared with the controls, prolonged the survival rate of posthemorrhagic rats from 50 to 85%.

[The effect of water-soluble steroids on the cardiovascular system]. / Vliianie vodorastvorimykh steroidov na serdechno-sosudistuiu sistemu.

Water-soluble analogues of steroidal hormones--prednisolone, estradiol, and testosterone on cardiac functional and hemodynamic parameters. Prednisolone and estradiol enhanced myocardial contractility and elevated systemic blood pressure, but testosterone did not affect cardiohemodynamic parameters. Prednisolone showed a drug administration rate-dependent cardiohemodynamic effect.