Schistosomiasis poses a serious threat to human health and remains a major tropical and parasitic disease in more than 70 countries. Praziquantel (PZQ) has been the primary treatment for schistosomiasis for nearly 4 decades. However, its efficacy against migratory-stage schistosomula is limited. Radicicol (RAD), a β-resorcylic acid lactone derived from Paecilomyces sp. strain SC0924, was investigated as an alternative treatment for Schistosoma japonicum. In vitro tests showed that within 72 h, RAD (10 μmol/liter) completely killed schistosomula of both skin and liver stages with an efficacy significantly higher than that of PZQ, although it was less potent against adult worms than PZQ. In vivo, RAD reduced worm burdens and liver eggs by 91.18% and 86.01%, respectively, by killing migratory-stage schistosomula. Optical microscopy and scanning electron microscopy revealed that RAD damaged the epiderm and tegument morphology of S. japonicum worms at various stages and altered their motility to different degrees. RAD exhibited schistosomicidal effects at different stages in vitro and in vivo, especially at the migratory stage, implying that its mechanism could be different from that of PZQ. Collectively, these results showed that RAD is promising as a lead for the development of drugs to control the migratory-stage schistosomula of S. japonicum.

中文翻译：

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Radicicol，一种抗日本血吸虫迁移期血吸虫的新型先导化合物

血吸虫病对人类健康构成严重威胁，在 70 多个国家仍然是主要的热带和寄生虫病。近 4 十年来，吡喹酮 (PZQ) 一直是血吸虫病的主要治疗方法。然而，它对迁移期血吸虫的功效是有限的。Radicicol (RAD)，一种源自拟青霉属的 β-间苯二酸内酯。菌株 SC0924 被研究作为日本血吸虫的替代治疗方法。体外试验表明，RAD (10 μmol/L) 在 72 小时内完全杀死皮肤和肝脏阶段的血吸虫，其功效显着高于 PZQ，尽管它对成虫的效力不如 PZQ。体内, RAD 通过杀死迁移阶段的血吸虫，分别减少了 91.18% 和 86.01% 的蠕虫负担和肝卵。光学显微镜和扫描电子显微镜显示，RAD在不同阶段破坏了S. japonicum蠕虫的表皮和外被形态，并不同程度地改变了它们的运动性。RAD表现出在不同阶段血吸虫效果在体外和在体内，特别是在迁徙阶段，这意味着它的机理可能不同于吡喹酮的不同。总的来说，这些结果表明 RAD 有望成为开发控制日本 S. japonicum迁移阶段血吸虫的药物的先导。