Dihydrobenz[e][1,4]oxazepin-2(3H)-ones, a new anthelmintic chemotype immobilising whipworm and reducing infectivity in vivo.
Trichuris trichiura is a human parasitic whipworm infecting around 500 million people globally, damaging the physical growth and educational performance of those infected. Current drug treatment options are limited and lack efficacy against the worm, preventing an eradication programme. It is therefore important to develop new treatments for trichuriasis. Using Trichuris muris, an established model for T. trichiura, we screened a library of 480 novel drug-like small molecules for compounds causing paralysis of the ex vivo adult parasite. We identified a class of dihydrobenz[e][1,4]oxazepin-2(3H)-one compounds with anthelmintic activity against T. muris. Further screening of structurally related compounds and resynthesis of the most potent molecules led to the identification of 20 active dihydrobenzoxazepinones, a class of molecule not previously implicated in nematode control. The most active immobilise adult T. muris with EC50 values around 25-50μM, comparable to the existing anthelmintic levamisole. The best compounds from this chemotype show low cytotoxicity against murine gut epithelial cells, demonstrating selectivity for the parasite. Developing a novel oral pharmaceutical treatment for a neglected disease and deploying it via mass drug administration is challenging. Interestingly, the dihydrobenzoxazepinone OX02983 reduces the ability of embryonated T. muris eggs to establish infection in the mouse host in vivo. Complementing the potential development of dihydrobenzoxazepinones as an oral anthelmintic, this supports an alternative strategy of developing a therapeutic that acts in the environment, perhaps via a spray, to interrupt the parasite lifecycle. Together these results show that the dihydrobenzoxazepinones are a new class of anthelmintic, active against both egg and adult stages of Trichuris parasites. They demonstrate encouraging selectivity for the parasite, and importantly show considerable scope for further optimisation to improve potency and pharmacokinetic properties with the aim of developing a clinical agent.
Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom.
Frederick A
FA
Partridge
Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
Emma A
EA
Murphy
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Nicky J
NJ
Willis
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Carole J R
CJ
Bataille
Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
Ruth
R
Forman
Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom.
Narinder
N
Heyer-Chauhan
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Bruno
B
Marinič
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Daniel J C
DJ
Sowood
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
Graham M
GM
Wynne
Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
Kathryn J
KJ
Else
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.|Department of Pharmacology, University of Oxford, Oxford, United Kingdom.
Angela J
AJ
Russell
Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom.
David B
0000-0003-0705-5242
DB
Sattelle
D000818:Animals; D000871:Anthelmintics / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology; D008124:Locomotion / Q000187:drug effects*; D051379:Mice; D010077:Oxazepines / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D014257:Trichuriasis / Q000517:prevention & control; D014258:Trichuris / Q000187:drug effects* / Q000502:physiology*
D000871:Anthelmintics; C000620802:OX02983; D010077:Oxazepines