Diuretic and potassium-sparing effect of isoquercitrin—An active flavonoid of Tropaeolum majus L

• Published in: Journal of ethnopharmacology Vol. 134; no. 2; pp. 210 - 215
• Main Authors: Gasparotto Junior, Arquimedes, Gasparotto, Francielly Mourão, Boffo, Marcos Aurelio, Lourenço, Emerson Luiz Botelho, Stefanello, Maria Élida Alves, Salvador, Marcos José, da Silva-Santos, José Eduardo, Marques, Maria Consuelo Andrade, Kassuya, Cândida Aparecida Leite
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 24.03.2011; Elsevier
• Subjects: Animals; Biological and medical sciences; Diuretics - isolation & purification; Diuretics - pharmacology; Dose-Response Relationship, Drug; General pharmacology; Hydrochlorothiazide - pharmacology; Hypertension - blood; Hypertension - drug therapy; Hypertension - urine; Isoquercitrin; Male; Medical sciences; Natriuretic; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Phytotherapy; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plant Extracts - therapeutic use; Plant Leaves; Potassium - blood; Potassium - metabolism; Potassium - urine; Quercetin - analogs & derivatives; Quercetin - isolation & purification; Quercetin - pharmacology; Quercetin - therapeutic use; Rats; Rats, Inbred SHR; Sodium - blood; Sodium - urine; Tropaeolaceae; Tropaeolum - chemistry; Tropaeolum majus; Urination - drug effects; Urine output; Natriuretic; Tropaeolaceae; Tropaeolum majus; Urine output; Isoquercitrin; Urine; Biological fluid; Pharmacognosy; Ornamental crop; Inorganic element; Flavonoid; Medicinal plant; Diuretic; Polyphenol; Dicotyledones; Angiospermae; Plant origin; Phenols; Flavone derivatives; Glycoside; Spermatophyta; Potassium
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2010.12.009

The diuretic and natriuretic activities of purified fraction (TMLR) and isoquercitrin, of Tropaeolum majus were evaluated in SHR. The urinary excretion rate was dose-dependently increased as well as Na+, with the advantage of an interesting potassium-sparing effect. Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic effects supporting the ethnopharmacological use of this plant as diuretic. In the present work, phytochemical investigation, guided by bio-assay in spontaneously hypertensive rats (SHR), was carried out in order to identify the compounds responsible for diuretic action. Chromatographic fractionation of the hydroethanolic extract yielded an active fraction (TMLR) rich in isoquercitrin. TMLR (25–100mg/kg) and isoquercitrin (5–10mg/kg), as well the reference drug hydrochlorothiazide (10mg/kg) were orally administered in a single dose or daily for 7 days to SHR. The urine excretion rate, pH, density, conductivity and content of sodium (Na+) and potassium (K+) electrolytes were measured in the urine of saline-loaded animals. The urinary excretion rate was dose-dependently increased in both TMLR and isoquercitrin groups, as well as Na+. Despite the changes in urinary excretion of electrolytes, the plasmatic levels of Na+ and K+ had not been changed. In addition, we did not find any evidence of renal toxicity or other adverse effects in these animals, even after prolonged treatment with TMLR or isoquercitrin. This research supports and extends the ethnomedicinal use of T. majus as diuretic. This activity seems to be associated to the presence of the flavonol isoquercitrin.