Radioimmunoassay for the Determination of the Steroidal Alkaloid Solasodine and Related Compounds in Living Plants and Herbarium Specimens¹

Abstract

A rapid, specific and sensitive radioimmunoassay for the determination of the steroidal alkaloid solasodine is described. The assay allows the detection of as little as 0.7 ng of solasodine glycosides (sola-sonine, solamargine) in crude plant extracts. The detailed distribution of solasodine in vegetative and generative parts of plants of Solanum laciniatum was investigated, and several thousand S. laciniatum plants were screened for individuals with high solasodine content. Plants which contained as much as 3.1 % of solasodine in the leaves were selected for further breeding. A taxonomic survey of the occurrence of solasodine in ca. 250 different species of the genus Solanum using herbarium material is given. 0.5 mg of a herbarium sample is more than sufficient for quantitative analysis.