Triterpenoids and coumarins from the leaves of Sterculia foetida Linn.

Introduction: Sterculia foetida Linn. is widely distributed in tropical countries. As the continuous study on the hexane and ethyl acetate extracts of Sterculia foetida leaves, the isolation and structural determination of four triterpenoids and two coumarins were addressed. Method: The crude extract was prepared from dried power of Sterculia foetida leaves by maceration method in ethanol. This extract was then separated by liquid-liquid partition with n-hexane, chloroform, and ethyl acetate, respectively, to obtain the corresponding extracts. The hexane and ethyl acetate extracts were applied to multiple silica gel column chromatography to yield six compounds. Their chemical structures were determined by the NMR data analysis as well as the comparison their spectroscopic data and physical properties with those of reported literature. Results: Four triterpenoid compounds, including betulinic acid (1), conyzasaponin G (2), taraxerol (3), and taraxer-14-ene- 1a,3b -diol (4), and two coumarins fraxetin (5), and aesculin (6) were identified. Conclusion: To the best of our knowledge, they have not been reported in the leaves of Sterculia foetida before, and compound 2 was known to present in Sterculia genus for the first time.