Sida tuberculata reduces oxidative stress and pain caused by the knee osteoarthritis.

Knee osteoarthritis (OA) cause pain and edema, as well as unbalance between the production of reactive oxygen species and antioxidant activity. These problems interfere with the articular function, leading to a significant loss of life quality. Sida tuberculata R.E.Fr. is an herbaceous plant belonging to the Malvaceae family found in southern Brazil. This plant has traditionally been consumed as an infusion and popularly used in the treatment of many diseases, with antioxidant and antimicrobial activity, reducing pain and inflammation.To verify the effects of S. tuberculata infusion obtained from leaves on oxidative, toxic and nociceptive parameters induced by knee OA in rats.Aqueous extracts of S. tuberculata were evaluated under phytochemical analyses. Knee Osteoarthritis was induced in rats with monosodium iodoacetate and treated with S. tuberculata infusion. The animals were treated orally with 3 doses of S. tuberculata infusion: 10, 30 and 100 mg/ml, for 14 days. For biochemical analyses, the following tests were performed: lipid peroxidation, carbonylated protein content, superoxide dismutase activity, non-protein thiol levels and myeloperoxidase activity. For the evaluation of pain and edema we verify mechanical and thermal hyperalgesia, spontaneous pain observation and measurement of knee edema with a caliper. For toxicity evaluation, the levels of aspartate aminotransferase, alanine aminotransferase and urea, as well as the relative weight of the organs were analyzed.The S. tuberculata phytochemical analyses showed the majority peak corresponding to 20-hydroxyecdysone (20HE). The plant infusion decreased damages related to oxidative stress in the blood serum. The ST groups presented pain decrease, lower neutrophil activity in the knee, and increased blood serum activity. Besides that, the ST infusion showed low levels of toxicity in blood serum, liver and kidney samples.S. tuberculata reduced the damage due to oxidative stress and pain caused by knee osteoarthritis in rats. In addition, the infusion presented no toxicity. Our results suggest that S. tuberculata seems to have a therapeutic potential in the osteoarthritis treatment.