Senecio alkaloids. Part III. Chemical investigations upon the Senecio species responsible for "bread-poisoning". The isolation of senecionine from Senecio ilicifolius Thunb. and a new alkaloid "rosmarinine" from Senecio rosmarinifolius Linn

Abstract

I. Two of the main Senecio species responsible for "breadpoisoning" in human beings in the Cape South-Western districts, viz., S. ilicifolius Thunb. and S. rosmarinifolius Linn., have been chemically examined for their toxic principles. II. From S. ilicifolius Thunb. a known alkaloid, Senecionine, C₁₈H₂₅O₅N, previously isolated by other workers from S. vulgaris, S. viscosus, S. squalidus and S. aureus, has been obtained. III. Senecionine is a stable alkaloid with m.p. 232° and very sparingly soluble in water. The alkaloid will not be destroyed during the baking of bread from flour of contaminated wheat. IV. S. rosmarinifolius Linn. contains a new alkaloid for which the name "Rosmarinine" is proposed. It has the formula C₁₈H₂₇O₆N, the melting-point 208°, it is extremely bitter and very sparingly soluble in water. It must be considered a dangerous poison when wheat becomes contaminated with S. rosmarinifolius or when animals graze on this plant. V. Rosmarinine has a specific rotation of -120.0° in chloroform and -94.0° in ethanol. Its nitrate has a melting-point of 218°C. and a specific rotation of -91.5° in water. VI. As a result of this chemical investigation and the nature of the toxic principles, the author urges the complete eradication of these Senecio plants which unfortunately occur very abundantly. This is considered the only remedy to prevent human deaths due to "bread-poisoning" and animal losses from chronic liver-cirrhosis.