A lupin alkaloid, (-)-tenuamine, was isolated from the stem parts of Maacki
a tenuifolia together with eight known alkaloids. The structure of (-)-tenu
amine was determined to be (-)-acetylaminomethylideneindolizidine by compar
ison of its chemical and spectroscopic data with those of (-)-lusitanine, (
+)-tashiromine and indolizidine.