[The diuretic effect of cornflower water extract]

The objective of this study was to evaluate and compare the effect of cornflower water extract and hydrochlorothiazide on diuresis, Na(+) and K(+) excretion, and the changes in the prostaglandin E(2) and kinins levels in the blood plasma.

Male Wistar rats were used in all experiments. Animals were divided into nine groups. Diuretic activity was investigated according to the technique proposed by E. B. Berchin; urinary electrolyte contents were analyzed by flame photometry. Prostaglandin E(2) content was measured by radioimmunoassay using (3)H isotopes, kinins--by enzymatic methods.

It has been established that in male rats, receiving hydrochlorothiazide, the volume of urine excreted two and four hours after the administration of the drug was by 18% and 17%, respectively, higher as compared to the rats that were given cornflower water extract (P<0.05). The diuretic effect of cornflower water extract was noted in the animal group receiving this extract as compared to the control group: after two hours, the volume of urine excreted increased from 2.03+/-0.03 mL to 2.44+/-0.04 mL and after four hours--from 3.88+/-0.07 mL to 5.35+/-0.1 mL. Administration of hydrochlorothiazide under the load of salts and water resulted in a higher excretion of sodium and potassium as compared to the effect of cornflower water extract. The highest prostaglandin levels were found in the blood plasma of the animals receiving hydrochlorothiazide. Under the load of salts and water, a 13% and 15% increase, respectively, in the amount of prostaglandins was observed in the animals that were given cornflower water extract compared to the control animals (P<0.05). The greatest increase in the amount of kinins was found in the groups of animals that were given hydrochlorothiazide under the load of salts and water (14% and 22%, respectively). Kinin levels did not differ statistically significantly between the control group and the groups receiving cornflower water extract.

Cornflower water extract possesses diuretic activity, but its effect was lower than that of hydrochlorothiazide.