Experimental diuretic effects of Rosmarinus officinalis and Centaurium erythraea

Herbal remedies are widely used in Moroccan pharmacopoeia. We assessed the diuretic effect of two medicinal plants: Rosmarinus officinalis L., Labiata e, and Centaurium erythraea L., Gentianaceae, both reputed for the treatmen t of urinary ailments. To determine the action of these herbs on urinary vo lume (UV) and the excretion of sodium (UNaV), potassium (UKV), and chloride (UClV), the aqueous extracts of both plants were administered daily to Wis ter rats for I week. The concentration of electrolytes and urea in plasma a nd creatinine clearance were also investigated. Daily oral administration o f the aqueous extracts of R. officinalis and C. erythraea at the dose of 10 ml/kg of 8 or 16% extract in distilled water significantly enhanced diures is in rats compared to the control group from the fifth day of treatment. F or R. officinalis at the dose of 8% the peak of urinary excretion of sodium , potassium and chloride was reached after 6 days of treatment (P < 0.001). The aqueous extract of of ii. offinicalis at the dose of 16% did not signi ficantly affect the excretion of water and electrolytes over a similar peri od but slight increases in urinary excretion of sodium and chloride on the seventh day and of potassium on the sixth day (P < 0.05) were observed. No increase was recorded for 24 h urinary excretion of Na+, K+ and Cl- during the first 4 days of treatment for the groups treated with C. erythraea at t he doses of 8 and 16% whereas their effects on the same parameters were hig hly significant thereafter. No change was observed in plasma electrolytes a nd urea in any group, except for a decrease in sodium and chloride concentr ation in the group treated with 16% of R. offinicalis. A decrease in creati nine clearance was demonstrated after treatment with 8% of R. officinalis a nd C. erythraea L. Our findings demonstrate a diuretic effect of aqueous ex tracts of R. officinalis L. and C. erythraea L. with the most effective dos e for water and electrolyte excretion being 8% for both plants. (C) 2000 El sevier Science Ireland Ltd. All rights reserved.