Water soluble compounds of Rosmarinus officinalis L. improve the oxidative and inflammatory states of rats with adjuvant-induced arthritis

Anti-inflammatory and antioxidant properties have been attributed to constituents of Rosmarinus officinalis. Considering the inflammatory nature of arthritis and the oxidative stress induced by the disease, this work aimed to investigate if R. officinalis is able to attenuate oxidative and inflammatory injuries caused by the disease. Rats with complete Freund's adjuvant induced arthritis were used. An aqueous extract of the rosemary leaves was administered orally. The parameters related to oxidative stress were measured in the liver, brain and plasma. The administration of the rosemary extract (RE) to arthritic rats diminished oxidative damage (e.g., less carbonylated proteins), improved the oxidative state (e.g., less reactive oxygen species) and also increased the antioxidant capacity by increasing the GSH level and the GSH/GSSG ratio and by almost normalizing the activity of several antioxidant enzymes. The treatment of arthritic rats with the extract also diminished paw edema, the number of leukocytes recruited in the femoro-tibial joint cavities and the weight of the lymph nodes and delayed the appearance of secondary lesions. Twelve phenolic compounds were identified and quantified in the aqueous RE, rosmarinic acid being the most abundant one. In addition, the extract also contains polysaccharides and proteins. The anti-inflammatory and antioxidant activities of the RE can be attributed, partly at least, to its content of polyphenolics with the strong possibility of synergistic interactions as well as metabolic activations. The results corroborate and amplify the general notion that rosemary aqueous extracts possess efficient anti-inflammatory agents and suggest that they are able to attenuate the oxidative stress inherent to arthritis.