We have studied on the constituents and the stereochemical aspects of lupin alkaloids in differentiated plants and undifferentiated tissue culture of Thermopsis species in Leguminous plants. A new alkaloid, (+)-lupanine N-oxide (14), have been isolated from T. lupinoides with nine known alkaloids (11-15, 17, 18, 21-23) (scheme 2). Two new alkaloids, (-)-O-acetylbabtifoline (19) and (-)-tetrahydrocytisine (24), have been isolated from T. chinensis with nine known alkaloids (11,12,16,17,18,20-23). The structure of new alkaloids were determined by spectroscopic methods and by chemical transformations. We have also studied on the production of alkaloids with callus culture of T. lupinoides and Sophora flavescens. The differentiated plants of T. lupinoides and T. chinensis accumulated (+)-lupanine (11)(7S:9S:11S) series alkaloids together with the antipodal (-)-anagyrine (17)(7R:9R:11R) series. It is interesting from the biosynthetic point of view that the sparteine-type alkaloids (11-14) and the α-pyridone-type alkaloids (16-23) have opposite absolute configuration with each other. However, (+)-lupanine (11)(6R:7S:9S:11S) was the only detectable alkaloid in the green callus of T. lupinoides. In the green callus of S. flavescens, matrine was the alkaloid mainly. The multiple shoots of S. flavescens additionally produced not only matrine but also 5,6-dehydrolupanine (16) and anagyrine (17). These results suggest that the biosynthesis of (+)-lupanine (11) and matrine, both of which are assumed to be the early intermediates in biosynthesis of lupin alkaloids, are related to greening of the tissues in Thermopsis and Sophora (scheme 1).
