The new pyrrole-imidazole and pyrrole-guanidine alkaloids 4-debromooroidin (1), 4-debromougibohlin (2), 5-debromougibohlin (3), and 5-bromopalau'amine (4), along with the known hymenidin (5) and (+)-monobromoisophakellin (6), have been isolated from a Dictyonella sp. marine sponge, collected at the Amazon River mouth. The bromine-substitution pattern observed for compounds 1, 2 and 4 is unusual among bromopyrrole alkaloids isolated from marine sponges. The 20S proteasome inhibitory activities of compounds 1-6 have been recorded, with 5-bromopalau'amine (4) being the most active in this series.

中文翻译：

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从Dictyonella sp。分离的蛋白酶体的溴吡咯生物碱抑制剂。海洋海绵在亚马逊河河口处收集。

新的吡咯-咪唑和吡咯胍生物碱4-debromooroidin（1），4-debromougibohlin（2），5-debromougibohlin（3）和5-bromopalau'amine（4）以及已知的膜虫素（5）和（+）-monobromoisophakellin（6），已从Dictyonella sp。分离。海洋海绵，收集在亚马逊河河口。从海洋海绵中分离出的溴吡咯生物碱中，化合物1、2和4的溴取代模式不同寻常。已经记录了化合物1-6的20S蛋白酶体抑制活性，其中5-溴palau'amine（4）在该系列中最活跃。