γ- and δ‑Lactams from the Leaves of Clausena lansium
journal contributionposted on 25.11.2015, 00:00 by De-Yang Shen, Thi Ngan Nguyen, Shwu-Jen Wu, Young-Ji Shiao, Hsin-Yi Hung, Ping-Chung Kuo, Daih-Huang Kuo, Tran Dinh Thang, Tian-Shung Wu
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.