Discovery of inhibitors of brassinin oxidase based on the scaffolds of the phytoalexins brassilexin and wasalexin

Brassinin oxidase, a unique detoxifying enzyme produced by the plant pathogen Leptosphaeria maculans, mediates the detoxification of the phytoalexin brassinin. Evaluation of different derivatives of the phytoalexins brassilexin and wasalexins A and B revealed 6-Cl-brassilexin to be the best competitive inhibitor discovered to date (Ki = 31 μM).