γ- and δ‑Lactams from the Leaves of Clausena lansium

Eight new clausenamides, including three γ-lactams (1–3), four δ-lactams (4–7), and an amide (8), and seven known lactams, including compounds 9–11, which were purified from natural sources for the first time, were characterized from the leaves of Clausena lansium. Their structures were elucidated using spectroscopic methods, and the absolute configurations were determined using electronic circular dichroism and single-crystal X-ray diffraction analyses with Cu Kα radiation. Compound 2 (50 μM) protected 22.24% of cortical neurons against Aβ25–35-induced cell death.

本研究从黄皮（Clausena lansium）的叶片中分离鉴定得到8个新黄皮酰胺（clausenamide）类化合物，其中包含3个γ-内酰胺（γ-lactam）类化合物（1~3）、4个δ-内酰胺（δ-lactam）类化合物（4~7）以及1个酰胺类化合物（8）；另获得7个已知内酰胺类化合物，其中化合物9~11为首次从天然资源中分离得到。所有化合物的结构均通过波谱学方法解析，其绝对构型通过电子圆二色谱（electronic circular dichroism）以及采用Cu Kα辐射的单晶X射线衍射（single-crystal X-ray diffraction）分析确定。化合物2在50 μM浓度下可使22.24%的皮层神经元免受Aβ25–35诱导的细胞死亡。