Evaluation of the diuretic effect of crude ethanol and saponin-rich extracts of Herniaria glabra L. in rats

Abstract

Ethnopharmacological relevance: Herniaria glabra L. popularly known in Morocco as "Herras lehjer" which means "Stonebreaker" in English is a plant that has been used in traditional medicine to treat edema, water retention, urinary diseases and renal problems including kidney stones.

Aim of the study: The present study aims to investigate the diuretic activity of the crude ethanol extract (CEE) and the saponin-rich extract (SRE) of the Herniaria glabra L.

Methods: CEE and SRE were prepared using maceration. SRE was obtained after using the selective liquid-liquid extraction method with organic solvents. Control (normal saline, 10 ml/kg), reference drug (furosemide 10 mg/kg) and three different doses (10 mg/kg, 50 mg/kg, 200 mg/kg) of the CEE and SRE were administered orally to male Wistar rats. The diuretic activity of the extracts was determined by measuring urine volume, urinary electrolyte and urine pH. The urine output measured at 5 h and 24 h, electrolyte concentration and pH were measured at 24 h duration. Data were analyzed by one way ANOVA followed by Dunnett's t-test.

Results: The findings indicated that the CEE significantly increased diuresis at 50 mg/kg and 200 mg/kg. Moreover, the SRE showed significant diuretic effect at all doses. CEE at a dose of 200 mg/kg increases the volume of urine by 81%, while SRE at a dose of 200 mg/kg increases the volume of urine by 114%. SRE demonstrated at 200 mg/kg the highest diuretic properties comparable to the reference drug. Na⁺, K⁺ and Cl^- urinary excretion was also significantly increased at 50 mg/kg and 200 mg/kg of CEE and at all doses of SRE. HPLC analysis revealed the presence of the saponin aglycones, the main ones are medicagenic acid and oleanolic acid, their content in CEE 3.1 ± 0.4%, 2.4 ± 0.3% respectively and in SRE 7.9 ± 0.2%, 5.9 ± 0.3% respectively. Triterpenoid saponins could be responsible for the diuretic activity of Herniaria glabra.

Conclusion: This study could make it useful to develop a pharmaceutical product based on purified saponin-rich extract of Herniaria glabra L. as a diuretic agent.

Keywords: Crude ethanol extract; Diuresis; Herniaria glabra L.; Rats; Saponin-rich extract; Urinary electrolyte.