Two novel Diels-Alder [4 + 2] cycloadducts of quaternary protoberberine alkaloids and fumaric acid monoanion, corydecumbenines A and B (1 and 2), and six known isoquinoline analogues (3–8) were isolated from the rhizomes of Corydalis decumbens. The planar structures of 1 and 2 were elucidated by extensive spectroscopic analysis including UV, IR, HRESIMS, 1D and 2D NMR. Chiral chromatography of 1 and 2 afforded two pairs of enantiomers (+)-corydecumbenine A (1a), (–)-corydecumbenine A (1b), (+)-corydecumbenine B (2a), and (–)-corydecumbenine B (2b), respectively, and their absolute configurations were determined by single-crystal X-ray crystallography and comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1b and 2b exhibited significant nitric oxide (NO) inhibitory activities in lipopolysaccharide (LPS)-stimulated BV-2 cells with IC₅₀ values of 11.6 and 16.2 μM, respectively, comparable to the positive control indomethacin (IC₅₀ = 10.3 μM), and they could also decrease the level of interleukin (IL)-1β in BV-2 cells in a dose-dependent manner. Most of the isolates showed neuroprotective effects against the injury of OGD/R-induced PC12 cells at 20 μM.

两种新型狄尔斯-阿尔德[4 + 2]季生物碱小檗碱和富马酸单阴离子的cycloadducts，corydecumbenines A和B（1和2），和六个已知异喹啉类似物（3 - 8）购自根茎分离延胡索斜卧。通过广泛的光谱分析（包括UV，IR，HRESIMS，1D和2D NMR）阐明了1和2的平面结构。1和2的手性色谱分离得到两对对映异构体（+）-双十二烷基苯丙氨酸A（1a），（-）-十二烷基苯丙氨酸A（1b），（+）-十二烷基苯丙氨酸B（2a）和（-）-二十二烷基苯丙氨酸B（2b），它们的绝对构型是通过单晶X射线晶体学以及实验和计算的电子圆二色性（ECD）光谱进行比较确定的。化合物1b和2b在脂多糖（LPS）刺激的B​​V-2细胞中表现出明显的一氧化氮（NO）抑制活性，其IC ₅₀值分别为11.6和16.2μM，与阳性对照消炎痛（IC ₅₀  = 10.3μM）相当，并且它们还能够降低白细胞介素的电平（IL）-1 β在BV-2细胞中呈剂量依赖性。大多数分离株在20μM时对OGD / R诱导的PC12细胞的损伤均表现出神经保护作用。