Isolation of the toxin responsible for gousiekte, a plant-induced cardiomyopathy of ruminants in southern Africa

Abstract

Gousiekte was induced in sheep and goats by the oral and intravenous (i/v) administration of methanolic and ethanolic precipitates of aqueous extracts of Pavetta harborii. Further purification of the toxic principle was carried out by dialysis and ion-exchange chromatography. The toxin was eluted from the cation-exchange resin with 1 mol/l of ammonium acetate and finally purified on Sephadex G-10 and silica gel. Spots on thin-layer chromatographic plates (TLC) were visualized with ninhydrin. Gousiekte was induced with the pure toxin after i/v administration in goats. The yield of pure toxin was about 10 mg/kg of dried leaves. A compound, indistinguishable from the above on TLC, was also isolated from the gousiekte-inducing plants Pavetta schumanniana, Fadogia homblei and Pachystigma pygmaeum.