Metabolism of the tomato saponin α-tomatine by Gibberella pulicaris

Abstract The ascomycete Gibberella pulicaris is able to metabolize the saponin α-tomatine within 2 h by first removing the complete lycotetraose moiety leading to the aglycone tomatidine. This product is further converted into 7α-hydroxy-tomatidine and the corresponding Δ 5 -dehydro product 7α-hydroxy-tomatidenol. Structural evidence for the hydroxylated main metabolite as well as the unsaturated minor product is based on MS and NMR measurements. The latter include the application of modern soft pulse 1 H NMR techniques allowing the definitive localization of the position of hydroxylation even for the few milligram quantities that could be obtained.