Ceramicines are a series of limonoids which were isolated from the barks of Malaysian Chisocheton ceramicus (Meliaceae), and were known to show various biological activity. Six new limonoids, ceramicines U–Z (1–6), with a cyclopentanone[α]phenanthrene ring system with a β-furyl ring at C-17 were isolated from the barks of C. ceramicus. Their structures were determined on the basis of the 1D and 2D NMR analyses, and their absolute configurations were investigated by CD spectroscopy. Ceramicine W (3) exhibited potent antimalarial activity against Plasmodium falciparum 3D7 strain with IC₅₀ value of 1.2 µM. In addition, the structure–antimalarial activity relationship (SAR) of the ceramicines was investigated to identify substituent patterns that may enhance activity. It appears that ring B and the functional groups in the vicinity of rings B and C are critical for the antimalarial activity of the ceramicines. In particular, bulky ester substituents with equatorial orientation at C-7 and C-12 greatly increase the antimalarial activity.

Graphical Abstract

中文翻译：

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Chisochetonceramicus 中的 Ceramicines U-Z 及其结构与抗疟活性关系研究

陶瓷素是从马来西亚Chisochetonceramicus （楝科）的树皮中分离出来的一系列柠檬苦素，已知具有多种生物活性。从C.ceramicus的树皮中分离出六种新的柠檬苦素类化合物，ceramicines U–Z ( 1 – 6 )，其具有环戊酮[α]菲环系统，在 C-17 处具有 β-呋喃基环。基于一维和二维核磁共振分析确定了它们的结构，并通过圆二色光谱研究了它们的绝对构型。Ceramicine W ( 3 ) 对恶性疟原虫3D7 菌株表现出有效的抗疟活性，IC ₅₀值为 1.2 µM。此外，还研究了陶瓷素的结构-抗疟活性关系（SAR），以确定可能增强活性的取代基模式。看来环 B 以及环 B 和环 C 附近的官能团对于陶瓷碱的抗疟活性至关重要。特别是，C-7 和 C-12 上具有赤道取向的大酯取代基大大提高了抗疟活性。

图形概要