[EN] The capacity of inhibition of the mammalian mitochondrial respiratory chain of brevioxime 5a, a natural insecticide compound isolated from Penicillium brevicompactum culture broth, and another 15 analogue compounds, other oximes 5b and 5c; two diastereomeric pyrrolidines 1c' and 1c"; five pyrrolines 3c', 3c" (diastereomers between them), 3a, 3b, and 6; two oxazines 4c' and 4c" (also diastereomers between them); and four pyrrol derivatives 7-10, are analyzed in this paper. Compounds 3b, 3c', 3c", 4c', 4c", 5b, 5c, 6, and 10 were found to be inhibitors of the integrated electron transfer chain (NADH oxidase activity) in beef heart submitochondrial particles (SMP), establishing that all of them except compound 3b and 6 only affected to complex I of the mitochondrial respiratory chain. The most potent product was 5b, with an IC50 of 0.27 mu M, similar to the IC50 values of other known complex I inhibitors. The diastereomeric pairs 1 c'/1c", 3c'/3c", 4c'/4c", and 5c have not been previously described. Chemical characterization, on the basis of spectral data, is also shown. We acknowledge the Fundacio¿n Jose¿ y Ana Royo for a postdoctoral grant to M.C.G., and the Conserjerı¿a de Educacio¿n y Ciencia de la C. Valenciana for the doctoral grant to M.P.L. This work has been supported by Oficina de Ciencia y Tecnologı¿a. I+D projects of the Generalitat Valenciana (Project GV01- 293), the Conselleria d Agricultura, Pesca i Alimentacio¿ (Project GVCAPA00-0529), and Fondos Europeos de Desarrollo Regional (FEDERFSE) of the European Union through the Fondo de Investigacio¿n Sanitaria (FIS 01/0406). Cantin Sanz, A.; López-Gresa, MP.; Gonzalez Más, MC.; Moya Sanz, MDP.; Miranda Alonso, MÁ.; Primo Millo, J.; Romero, V.... (2005). Novel inhibitors of the mitochondrial respiratory chain: Oximes and pyrrolines isolated from Penicillium brevicompactum and synthetic analogues. Journal of Agricultural and Food Chemistry. 53(21):8296-8301. https://doi.org/10.1021/jf058075f