Pyranocarbazole alkaloids, isolated from Clausena cambodiana leaves, as a pancreatic cholesterol esterase inhibitor, and their HPLC–DAD quantitative determination method

A bioassay-guided isolation method was performed with pancreatic cholesterol esterase as a target enzyme. Four pyranocarbazole alkaloids, 8-hydroxymahanimbine ( 1 ), mahanine ( 2 ), mahanimbicine ( 3 ) and mahanimbine ( 4 ) were isolated from Clausena cambodiana Guill leaves for the first time. Furthermore, compound 1 has never before been isolated as a natural product. The chemical structures of the isolated compounds were elucidated by comprehensive spectroscopic analysis, including 1D and 2D-NMR, and comparison with published data. Compounds 1 and 2 exhibited potent inhibitory activity against pancreatic cholesterol esterase, with IC 50 values of 48.56 and 34.56 µg/mL, respectively. The HPLC–DAD method for the quantification of four pyranocarbazole alkaloids from C. cambodiana leaves was also validated . The method was simple, accurate, rapid and reliable, and can be used for the quality control of C. cambodiana leaves. Our findings indicate that C. cambodiana leaves could be used as a functional food or pharmaceutical ingredient for the prevention and treatment of hypercholesterolemia.