Six undescribed quinoline alkaloids, named dasycarines A-E, and 18 known ones were isolated from the root bark of Dictamnus dasycarpus. All the structures were elucidated on the basis of comprehensive analysis of UV, IR, NMR, and HRMS spectroscopic data, and the absolute configurations were assigned via comparison of the calculated and experimental ECD data. (+)-Dasycarine A (1a) and (-)-Dasycarine A (1b) are a pair of enantiomers of dimeric furoquinoline alkaloid, which are the first dimeric via [2 + 2] cycloaddition of furan. The structure and absolute configuration of (-)-dasycarine A was determined via X-ray crystallography. Additionally, all the isolated compounds were tested for their inhibitory effects on NO production stimulated by LPS in BV-2 microglial cells. Three compounds showed strong inhibition with IC50 values below 5.0 μM; nine compounds exhibited inhibition with IC50 values in the range of 7.8-28.4 μM. Furthermore, we demonstrated that preskimmianine suppressed the levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nuclear factor kappa B (NF-κB) in LPS-induced BV-2 microglial cells.

中文翻译：

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白菖蒲根皮抗炎喹啉生物碱

从 Dictamnus dasycarpus 的根皮中分离出 6 种未描述的喹啉生物碱，命名为 dasycarines AE，以及 18 种已知的生物碱。在综合分析UV、IR、NMR和HRMS光谱数据的基础上阐明了所有结构，并通过计算和实验ECD数据的比较来指定绝对构型。(+)-Dasycarine A (1a) 和 (-)-Dasycarine A (1b) 是二聚呋喃喹啉生物碱的一对对映异构体，它们是第一个通过呋喃 [2 + 2] 环加成形成的二聚体。(-)-dasycarine A 的结构和绝对构型是通过 X 射线晶体学确定的。此外，测试了所有分离的化合物对 BV-2 小胶质细胞中 LPS 刺激的 NO 产生的抑制作用。三种化合物表现出强抑制作用，IC50 值低于 5.0 μM；九种化合物表现出抑制作用，IC50 值在 7.8-28.4 μM 范围内。此外，我们证明了 preskimmianine 抑制了 LPS 诱导的促炎细胞因子的水平，如肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）和核因子κB（NF-κB）的水平。 BV-2 小胶质细胞。