The chemical diversity of annelids, particularly those belonging to the class Sipuncula, remains largely unexplored. However, as part of a Marine Biodiscovery program in Ireland, the peanut worm Phascolosoma granulatum emerged as a promising source of unique metabolites. The purification of the MeOH/CH₂Cl₂ extract of this species led to the isolation of six new linear guanidine amides, named phascolosomines A–F (1–6). NMR analysis allowed for the elucidation of their structures, all of which feature a terminal guanidine, central amide linkage, and a terminal isobutyl group. Notably, these guanidine amides were present in unusually high concentrations, comprising ∼3% of the dry mass of the organism. The primary concentration of the phascolosomines in the viscera is similar to that previously identified in linear amides from sipunculid worms and marine fireworms. The compounds from sipunculid worms have been hypothesized to be toxins, while those from fireworms are reported to be defensive irritants. However, screening of the newly isolated compounds for inhibitory bioactivity showed no significant inhibition in any of the assays conducted.

中文翻译：

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来自海洋丝虫类粒状体的高浓度线性胍酰胺

环节动物的化学多样性，特别是属于星虫纲的环节动物，在很大程度上仍未被探索。然而，作为爱尔兰海洋生物发现计划的一部分，花生蠕虫颗粒状囊虫成为独特代谢物的有前途的来源。该物种的MeOH/CH ₂ Cl ₂提取物的纯化导致分离出六种新的线性胍酰胺，命名为 phascolosomines A–F ( 1 – 6 )。核磁共振分析可以阐明它们的结构，所有这些结构都具有末端胍、中心酰胺键和末端异丁基。值得注意的是，这些胍酰胺的浓度异常高，约占生物体干质量的 3%。内脏中的囊体胺的主要浓度与先前在来自丝虫和海洋火虫的线性酰胺中鉴定的浓度相似。来自 sipunculid 蠕虫的化合物被假设为毒素，而来自火虫的化合物据报道是防御性刺激物。然而，对新分离的化合物的抑制生物活性的筛选表明，在进行的任何测定中都没有显着的抑制作用。