Abstract: From the whole plants of Piptanthus concolor Harrow(Leguminosae), a new alkaloid, 5-α-hydroxyl-7, 17-dehydroisolupanine (Ⅴ), and other four known compounds, thermopsine (Ⅰ), anagyrine (Ⅱ), cytisine (Ⅲ) and β-sitosterol (Ⅳ) were isolated. Their structures were identified on the basis of EIMS,¹H NMR,¹³C NMR,DEPT, IRand UVdata and the comparison with the authentic samples. Meanwhile, the results of this study support the close relation among the genera, piptanthus, thermopsis and ammopiptanthus in chemotaxonomy.

Key words: Piptanthus concolor Harrow, Leguminoseae, 5-α-Hydroxyl-7,17-dehydroisolupanine, Chemotaxonomy