A new dinorxanthane and chromone from the root of Tithonia diversifolia

Abstract

Diversifolide [4,15-dinor-3-hydroxy-1(5)-xanthen-12,8-olide], a novel dinorxanthane sesquiterpene, and a new chromone, 6-acetyl-7-hydroxy-2,3- dimethylchromone, together with four known compounds, 2-deacetyl-11β,13- dihydroxyxanthinin, 2-acetyl-2,2-dimethylchromene, 6-acetyl-7-hydroxy-2,2- dimethylchromene, and 6-acetyl-7-methoxy-2,2-dimethylchromene were isolated from the root of Tithonia diversifolia. Their structures were spectroscopically determined by 2D-NMR experiments, including heteronuclear multiple bond correlation and nuclear overhauser enhancement spectroscopy.