Evaluation of diuretic activity of Amaranthus spinosus Linn. aqueous extract in Wistar rats

Ethnopharmacological relevance: Traditional Siddha medicine literature claims that the Amaranthus spinosus Linn. (family: Amaranthaceae) whole plant possesses diuretic property. Aim of the study: To evaluate the diuretic potential of Amaranthus spinosus aqueous extract (ASAE) in rats. Material and methods: Different concentrations of ASAE (200, 500, 1000, 1500 mg/kg), thiazide (10 mg/kg) and vehicle were orally administered to rats (n = 6 animals per group) and their urine output was collected after 24 h. Volume, pH, Na ⁺, K ⁺ and Cl ^- concentrations of urine were estimated. Results: ASAE produced increase in Na ⁺, K ⁺, Cl ^- excretion, caused alkalinization of urine, showed strong saluretic activity and carbonic anhydrase inhibition activity. These effects were observed predominantly at 500 mg/kg dose and there was no dose-response relationship. Conclusion: Our study strongly suggests that the Amaranthus spinosus is acting as a thiazide like diuretic with carbonic anhydrase inhibitory activity which restates the claim as diuretic herb in Siddha medicine.