Tempone André Gustavo, Pimenta Daniel Carvalho, Lebrun Ivo, Sartorelli Patrícia, Taniwaki Noemi N, de Andrade Heitor Franco, Antoniazzi Marta Maria, Jared Carlos
Laboratório de Toxinologia Aplicada, Departamento de Parasitologia, Instituto Adolfo Lutz, Av. Dr. Arnaldo 355, 8 degrees andar CEP 01246-000, São Paulo, Brazil.
Toxicon. 2008 Jul;52(1):13-21. doi: 10.1016/j.toxicon.2008.05.008. Epub 2008 Jul 15.
Amphibian skin secretions are considered a rich source of biologically active compounds and are known to be rich in peptides, bufadienolides and alkaloids. Bufadienolides are cardioactive steroids from animals and plants that have also been reported to possess antimicrobial activities. Leishmaniasis and American Trypanosomiasis are parasitic diseases found in tropical and subtropical regions. The efforts toward the discovery of new treatments for these diseases have been largely neglected, despite the fact that the only available treatments are highly toxic drugs. In this work, we have isolated, through bioguided assays, the major antileishmanial compounds of the toad Rhinella jimi parotoid macrogland secretion. Mass spectrometry and (1)H and (13)C NMR spectroscopic analyses were able to demonstrate that the active molecules are telocinobufagin and hellebrigenin. Both steroids demonstrated activity against Leishmania (L.) chagasi promastigotes, but only hellebrigenin was active against Trypanosoma cruzi trypomastigotes. These steroids were active against the intracellular amastigotes of Leishmania, with no activation of nitric oxide production by macrophages. Neither cytotoxicity against mouse macrophages nor hemolytic activities were observed. The ultrastructural studies with promastigotes revealed the induction of mitochondrial damage and plasma membrane disturbances by telocinobufagin, resulting in cellular death. This novel biological effect of R. jimi steroids could be used as a template for the design of new therapeutics against Leishmaniasis and American Trypanosomiasis.
两栖动物的皮肤分泌物被认为是生物活性化合物的丰富来源，已知富含肽、蟾毒二烯羟酸内酯和生物碱。蟾毒二烯羟酸内酯是动植物来源的具有心脏活性的类固醇，也有报道称其具有抗菌活性。利什曼病和美洲锥虫病是在热带和亚热带地区发现的寄生虫病。尽管目前唯一可用的治疗方法是高毒性药物，但针对这些疾病新治疗方法的研究工作在很大程度上被忽视了。在这项研究中，我们通过生物导向分析，从蟾蜍吉米氏蟾蜍（Rhinella jimi）腮腺大腺分泌物中分离出了主要的抗利什曼原虫化合物。质谱分析以及氢核磁共振（1H）和碳核磁共振（13C）光谱分析能够证明活性分子是远华蟾毒精和嚏根草苷元。这两种类固醇对杜氏利什曼原虫（Leishmania (L.) chagasi）前鞭毛体均有活性，但只有嚏根草苷元对克氏锥虫（Trypanosoma cruzi）锥鞭毛体有活性。这些类固醇对利什曼原虫的细胞内无鞭毛体有活性，且不会激活巨噬细胞产生一氧化氮。未观察到对小鼠巨噬细胞的细胞毒性和溶血活性。对前鞭毛体的超微结构研究表明，远华蟾毒精可诱导线粒体损伤和质膜紊乱，导致细胞死亡。吉米氏蟾蜍类固醇的这种新生物效应可作为设计抗利什曼病和美洲锥虫病新疗法的模板。
