Cocoa contains flavonoids with antioxidant properties. The aim of this study was to ascertain the effect
of cocoa intake on oxidative stress associated with a model of chronic inflammation such as adjuvant
arthritis. Female Wistar rats were fed with a 5% or 10% cocoa-enriched diet or were given p.o. a quercetin
suspension every other day for 10 days. Arthritis was induced by a heat-killed Mycobacterium butyricum
suspension. Reactive oxygen species (ROS) produced by macrophages, and splenic superoxide dismutase
(total, cytoplasmic and mitochondrial) and catalase activities were determined. Clinically, joint swelling
in arthritic rats was not reduced by antioxidants; however, the 5% cocoa diet and quercetin administration
reduced ROS production. Moreover, the 5% cocoa diet normalized the activities of superoxide
dismutase and catalase. In conclusion, a cocoa diet reduces the oxidative stress associated with a chronic
inflammatory pathology, although it was not enough to attenuate joint swelling.