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 IC₅₀ 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.

以胰胆固醇酯酶为靶标酶，进行了生物测定指导的分离方法。首次从Clausena cambodiana Guill叶片中分离出四种吡喃咔唑生物碱，即8-hydroxymahanimbine（1），mahanine（2），mahanimbicine（3）和mahanimbine（4）。此外，化合物1从未作为天然产物被分离出来。通过全面的光谱分析，包括1D和2D-NMR，并与已发表的数据进行比较，阐明了分离出的化合物的化学结构。化合物1和2对胰腺胆固醇酯酶表现出有效的抑制活性，具有IC_50个值分别为48.56和34.56 µg / mL。还验证了用HPLC-DAD方法定量测定柬埔寨假单胞菌叶片中四种吡喃咔唑生物碱的含量。该方法简便，准确，快速，可靠，可用于C. cambodiana叶片的质量控制。我们的发现表明，C。cambodiana叶片可用作预防和治疗高胆固醇血症的功能性食品或药物成分。