Diuretic activity and toxicity of some Verbascum nigrum extracts and fractions

AbstractContext. Verbascum nigrum L. (Scrophulariaceae) is a perennial plant used in folk medicine for the treatment of kidney diseases due to its presumable diuretic properties.Objective: We investigated the diuretic activity and toxicity of extracts from different parts of V. nigrum and identified a group of compounds responsible for the biological effect.Materials and methods: Five ethanol extracts from herb, roots, flowers, leaves and stems as well as five fractions of polar compounds isolated from herb of V. nigrum were orally administrated as a single dose of 50 mg/kg to rats. Urinary excretion and electrolyte content were measured at 3 and 6 h after the treatment. The acute toxicity of the V. nigrum extracts and fractions was evaluated in mice.Results: All extracts, except the one prepared from the roots, showed a significant increase of the urine output within first 3 h after their administration. The extract from stems was the most active, inducing urine output of 14.6 ± 0.8 ml/kg BW versus 5.2 ±...