Ten bromotyrosine alkaloids were isolated and characterised from the marine sponge Aplysinella rhax (de Laubenfels 1954) collected from the Fiji Islands, which included one new bromotyrosine analogue, psammaplin P and two other analogues, psammaplin O and 3‐bromo‐2‐hydroxy‐5‐(methoxycarbonyl)benzoic acid, which have not been previously reported from natural sources. HR‐ESI‐MS, 1D and 2D NMR spectroscopic methods were used in the elucidation of the compounds. Bisaprasin, a biphenylic dimer of psammaplin A, showed moderate activity with IC50 at 19±5 and 29±6 μM against Trypanzoma cruzi Tulahuen C4, and the lethal human malaria species Plasmodium falciparum clone 3D7, respectively, while psammaplins A and D exhibited low activity against both parasites. This is the first report of the antimalarial and antitrypanosomal activity of the psammaplin‐type compounds. Additionally, the biosynthesis hypotheses of three natural products were proposed.

中文翻译：

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从斐济海洋海绵 Aplysinella rhax 中分离的溴酪氨酸生物碱和新类似物的抗寄生虫活性

从斐济群岛收集的海海绵 Aplysinella rhax (de Laubenfels 1954) 中分离并表征了十种溴酪氨酸生物碱，其中包括一种新的溴酪氨酸类似物 psammaplin P 和另外两种类似物 psammaplin O 和 3-bromo-2-hydroxy-5 -（甲氧基羰基）苯甲酸，以前没有从天然来源报道过。HR-ESI-MS，一维和二维核磁共振光谱方法用于阐明化合物。Bisaprasin 是 psammaplin A 的联苯二聚体，对克氏锥虫 C4 和致命的人类疟疾物种恶性疟原虫克隆 3D7 分别显示出中等活性，IC50 为 19±5 和 29±6 μM，而 psammaplins A 和 D 表现出低活性对抗这两种寄生虫。这是 psammaplin 型化合物抗疟和抗锥虫活性的首次报告。此外，还提出了三种天然产物的生物合成假说。