Leptodactylidae是两栖动物科家族，分为三个亚科：Leiuperinae、Leptodactylinae和Paratelmatobiinae。研究过属于Leptodactylinae亚科的青蛙皮肤中的宿主防御肽（HDP），但关于Leiuperinae的物种中的肽的信息有限。在特立尼达收集的内啮蛙Engystomops pustulosus（Leiuperinae）通过肽组学分析多巴胺能刺激的皮肤分泌物，从中分离并结构表征了先前未知的脓疮素-1（FWKADVKEIG KKLAAKLAEELAKKLGEQ），[Q28E]脓疮素-1（脓疮素-2）和脓疮素-3（DWKETAKELLKKIGAKVAQVISDKLNPAPQ）。这些肽的主要结构与先前描述的青蛙皮肤HDP的结构不同。此外，分泌物中含有结构类似于之前在蛙科家族Dicroglossidae的皮肤分泌物中鉴定的虎尾蛙素（tigerinin）的tigerinin-1EP（GCKTYLIEPPVCT）。脓疮素-1和-3在25％三氟乙醇水和细胞膜模型（十二烷基硫酸钠和十二烷基磷酸胆碱胶束）存在下采用延伸的α-螺旋构象。脓疮素-1和-3对人类肿瘤细胞系（A549、MDA-MB-231和HT29）显示出细胞毒活性，但由于对非恶性人脐静脉内皮细胞具有相近的细胞毒活性，这些肽的用于开发成抗癌药物的治疗潜力有限。这些肽对大肠杆菌显示出微弱的抗菌活性（最低抑菌浓度（MIC）= 125 µM），但对金黄色葡萄球菌无活性。Tigerinin-1EP对肿瘤细胞和细菌均无活性。© 2023. The Author(s).

The amphibian family Leptodactylidae is divided into three sub-families: Leiuperinae, Leptodactylinae, and Paratelmatobiinae. Host-defense peptides (HDPs) present in the skins of frogs belonging to the Leptodactylinae have been studied extensively, but information is limited  regarding peptides from Leiuperinae species. Peptidomic analysis of norepinephrine-stimulated skin secretions from the Tungara frog Engystomops pustulosus (Leiuperinae) collected in Trinidad led to the isolation and structural characterization of previously undescribed pustulosin-1 (FWKADVKEIG KKLAAKLAEELAKKLGEQ), [Q28E] pustulosin-1 (pustulosin-2), and pustulosin-3 (DWKETAKELLKKIGAKVAQVISDKLNPAPQ). The primary structures of these peptides do not resemble those of previously described frog skin HDPs. In addition, the secretions contained tigerinin-1EP (GCKTYLIEPPVCT) with structural similarity to the tigerinins previously identified in skin secretions from frogs from the family Dicroglossidae. Pustulosin-1 and -3 adopted extended α-helical conformations in 25% trifluoroethanol-water and in the presence of cell membrane models (sodium dodecylsulfate and dodecylphosphocholine micelles). Pustulosin-1 and -3 displayed cytotoxic activity against a range of human tumor-derived cell lines (A549, MDA-MB-231, and HT29), but their therapeutic potential for development into anti-cancer agents is limited by their comparable cytotoxic activity against non-neoplastic human umbilical vein endothelial cells. The peptides also displayed weak antimicrobial activity against Escherichia coli (MIC = 125 µM) but were inactive against Staphylococcus aureus. Tigerinin-1EP was inactive against both the tumor-derived cells and bacteria.© 2023. The Author(s).