Eighteen cassane diterpenoids, including five new lactam-type (4–8), 12 new lactone-type (1–3 and 9–17), and one known compound (18), were isolated from Caesalpinia sinensis. To our knowledge, this is the first study on the seed kernels of C. sinensis, and cassane derivatives were discovered in this plant for the first time. Their structures including absolute configurations were established by extensive spectroscopic methods complemented with single-crystal X-ray diffraction analyses and ECD calculations. Compounds 4–8 were identified as a group of rare cassane diterpenoids possessing a lactam D-ring instead of a typical lactone moiety. Biological evaluation revealed that compounds 4–6 exhibited effective inhibitory effects on NO production in the LPS-induced RAW 264.7 macrophages, with IC₅₀ values in the range 8.2–11.2 μM. Compound 4 suppressed the excessive production of NO by down-regulating the expression of inducible nitric oxide synthase enzymes (iNOS) and reducing the enzymatic activity of iNOS. Moreover, the intermolecular interaction and binding mode between compound 4 and iNOS were elaborated by conducting a molecular docking study.

中文翻译：

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黄柏籽仁中的抗炎卡桑型二萜类化合物

十八cassane二萜类化合物，其中包括五个新的内酰胺型（4 - 8），12个新的内酯型（1 - 3和9 - 17），和一个已知化合物（18），从分离的云实吸虫。据我们所知，这是首次对中华绒螯蟹籽仁的研究，首次在该植物中发现了卡桑烷衍生物。它们的结构包括绝对构型是通过广泛的光谱方法建立的，辅以单晶 X 射线衍射分析和 ECD 计算。化合物4 – 8被鉴定为一组具有内酰胺 D 环而不是典型的内酯部分的稀有卡桑二萜。生物学评价表明，化合物4 - 6显示出对NO产生有效的抑制作用在LPS诱导的RAW 264.7巨噬细胞，用IC _50个范围为8.2-11.2μM值。化合物4通过下调诱导型一氧化氮合酶 (iNOS) 的表达和降低 iNOS 的酶活性来抑制 NO 的过度产生。此外，通过进行分子对接研究，详细阐述了化合物4与 iNOS之间的分子间相互作用和结合模式。