Characterization of novel steroidal alkaloids from tubers of solanum species by combined gas chromatography—mass spectrometry : Implications for potato breeding

Wild Solanum species are widely used in potato breeding as a source of valuable germplasm. Together with desired characteristics, toxic steroidal glycoalkaloids (SGAs), including unidentified SGAS, are sometimes transferred from the wild species to the cultivated potato. In this study, steroidal alkaloids (SAs) which originated from unidentified aglycones of SGAs found in tubers of Solanum species were characterized using retention indices, gas chromatography—mass spectrometry, high-resolution mass spectrometry (resolution 20 000) and hydrolysis in two-phase systems. All SAs possessed a solanidane skeleton and were probably substituted or dehydrogenated forms of solanidine. Most of these SAs have not been reported before. Analysis of the SGAs of three wild Solanum species and one primitive cultivated subspecies used in potato breeding, showed that the total SGA contents varied widely (403-2228 mg kg −1 fresh tuber) as did the concentrations of the individual SGAs within a species. The implications of the results are discussed from the viewpoints of breeding for resistance against pathogens or insects and of food safety of household potatoes.