Nine new monoterpenoid indole alkaloids, uncarialins A-I (1-9), were isolated from Uncaria rhynchophylla as well as 14 known analogues (10-23). Their structures were determined by HRESIMS, 1D and 2D NMR, and experimental and calculated electronic circular dichroism data. Compounds 5, 7, 15, and 22 displayed significant agonistic effects against the 5-HT1A receptor with EC50 values of 2.2 ± 0.1, 0.1 ± 0.1, 1.6 ± 0.3, and 2.0 ± 0.5 μM, respectively. The mechanisms of action of these four compounds with the 5-HT1A receptor were investigated by molecular docking, and the results suggested that amino acid residues Asp116, Thr196, Asn386, and Tyr390 played critical roles in the observed activity of the above-mentioned compounds.

中文翻译：

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Uncarialins AI，来自钩藤Uncaria rhynchophylla的单萜类吲哚生物碱，是5-HT1A受体的天然激动剂。

从花钩藤（Uncaria rhynchophylla）和十四种已知类似物（10-23）中分离出九种新的单萜类吲哚生物碱，uncarialins AI（1-9）。通过HRESIMS，1D和2D NMR以及实验和计算的电子圆二色性数据确定了它们的结构。化合物5、7、15和22对5-HT1A受体表现出显着的激动作用，EC50值分别为2.2±0.1、0.1±0.1、1.6±0.3和2.0±0.5μM。通过分子对接研究了这四种化合物与5-HT1A受体的作用机理，结果表明氨基酸残基Asp116，Thr196，Asn386和Tyr390在观察到的上述化合物的活性中起关键作用。