Methyl jasmonate (MeJA), common in the plant kingdom, is capable of reducing articular and hepatic
inflammation and oxidative stress in adjuvant-induced arthritic rats. This study investigated the actions of orally administered MeJA (75-300 mg/kg) on
inflammation, oxidative stress and selected
enzyme activities in the brain of Holtzman rats with adjuvant-induced
arthritis. MeJA prevented the
arthritis-induced increased levels of
nitrites,
nitrates,
lipid peroxides,
protein carbonyls and
reactive oxygen species (ROS). It also prevented the enhanced activities of
myeloperoxidase and
xanthine oxidase. Conversely, the diminished
catalase and
superoxide dismutase activities and
glutathione (GSH) levels caused by
arthritis were totally or partially prevented. Furthermore, MeJA increased the activity of the mitochondrial
isocitrate dehydrogenase, which helps to supply
NADPH for the mitochondrial
glutathione cycle, possibly contributing to the partial recovery of the GSH/
oxidized glutathione (
GSSG) ratio. These positive actions on the
antioxidant defenses may counterbalance the effects of MeJA as enhancer of ROS production in the mitochondrial respiratory chain. A negative effect of MeJA is the detachment of
hexokinase from the mitochondria, which can potentially impair
glucose phosphorylation and metabolism. In overall terms, however, it can be concluded that MeJA attenuates to a considerable extent the negative effects caused by
arthritis in terms of
inflammation and oxidative stress.