Acridone alkaloids from the root bark of Severinia buxifolia in Hainan.

Eight new acridone alkaloids, buxifoliadines-A--H together with nine known acridone compounds, were isolated and characterized from the root bark of Severinia buxifolia which was collected in Hainan province, China. Their structures were determined by spectroscopic methods. The relationship between acridone alkaloids with collecting area is discussed. The 13C-NMR spectra of the prenyl substituents at C-2 and/or C-4 of N-unsubstituted acridone alkaloids are also discussed.