Abstract
Two new xanthones, 6-hydroxy-3,7-dimethoxy-8-(3-methylbut-2-enyl)-6′,6′-dimethyl-5′-hydroxy-4′,5′-dihydropyrano(2′,3′:1,2)xanthone (1) and 6-hydroxy-3,7-dimethoxy-8-(2-oxo-3-methylbut-3-enyl)-6′,6′-dimethyl-5′-hydroxy-4′,5′-dihydropyrano(2′,3′:1,2)xanthone (2), have been isolated from the stems of Cratoxylum cochinchinense (Lour.) Blume. Their structures were established on the basis of spectroscopic analysis.
Acknowledgements
The authors thank Prof. Hao Zhang, West China School of Pharmacy, Sichuan University for identification of the plant materials. We are grateful to Prof. Yang Ye, the Shanghai Institute of Materia Medica of Chinese Academy of Science for measuring the HR-TOF-MS. The authors thank Ying-Hui Duan also for IR and UV data measurements. This work was supported by grants from the National Natural Science of Foundation of China (No. 30600777), China Postdoctoral Science Foudation (No. 20070410245), and Counterpart Funds of Science and Technology Program of Shenzhen in 2007.