Three novel zwitterionic alkaloids—ningpoensine A (1) and a pair of epimers, ningpoensines B/C (2a/2b)—with unprecedented molecular skeletons were isolated from the root of Scrophularia ningpoensis. Their structures were established by extensive spectroscopic analyses, and the absolute configuration of ningpoensine A was determined by quantum chemical calculations. A biosynthetic pathway leading to ningpoensines A–C from harpagide and natural amino acids is proposed. Ningpoensines B/C tended to promote wound closure in human embryonic keratinocytes.

中文翻译：

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Ningpoensines A–C：来自玄参的不寻常的两性离子生物碱

从玄参玄参中分离出三种新型的两性离子生物碱-宁朴素A（1）和一对差向异构体，宁朴素B / C（2a / 2b），它们具有空前的分子骨架。通过广泛的光谱分析确定了它们的结构，并且通过量子化学计算确定了神经氨酸A的绝对构型。有人提出了从harpagide和天然氨基酸导致宁珀森碱A–C的生物合成途径。Ningpoensines B / C倾向于促进人类胚胎角质形成细胞的伤口闭合。