Preliminary Pharmacologic Evaluation of Spigelia anthelmia Aerial Parts

Abstract

Fractions A, B, C and D obtained from an ethanol extract of the aerial portions of Spigelia anthelmia were screened for their qualitative activity. The intraperitoneal LD₅₀ in mice of the ethanol extract was found to be 222 mg/kg. Fraction A produced contractions of both guinea pig and rat isolated ileums. This effect appeared to be associated with H, receptors, as chlorpheniramine blocked 100% of the contractile response. Fraction A also produced hypotensive and bradycardic effects in the anesthetized cat. These effects appeared to be associated with muscarinic receptors since they were completely blocked by atropine. The intraperitoneal injection of Fraction A in anesthetized rats produced hypotension, bradycardia and a variable effect on cardiac contraction. The intravenous infusion in rats of Fractions A and C produced a prompt more or less short-lasting hypertension after 1 and 10 mg/kg and a dose of 30 mg/kg led to acute lethal intoxication with signs of cardiorespiratory depression. Fractions B and D under the same experimental conditions were less active with regard to cardio-depression.