Effect of Hautriwaic Acid Isolated from Dodonaea viscosa in a Model of Kaolin/Carrageenan-Induced Monoarthritis.

In the present work, the antiarthritic activity of hautriwaic acid is reported. This ent-clerodane diterpene isolated from Dodonaea viscosa was evaluated in mice using a kaolin/carrageenan-induced monoarthritis model. The inflammation observed in the joint (knee) on days 1-8 ranged from 50-70 %. After 10 days of treatment with different doses of hautriwaic acid (5, 10, 20 mg/kg), a decrease in knee inflammation was detected. This recovery was observed with both reference drugs, methotrexate (1 mg/kg) and diclofenac (0.75 mg/kg). In these groups of mice, the concentration of proinflammatory cytokines interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha in the joint was significantly lower than that of the negative control group (animals with damage without any treatment). The negative control group presented a decrease in the concentration of interleukin-10, while the groups that received hautriwaic acid at different dose exhibited an increase in this interleukin. This anti-inflammatory cytokine was not modified in the joint of mice with diclofenac, but in mice that received methotrexate, a significant decrease was observed. Hautriwaic acid isolated from D. viscosa diminished the joint edema induced by this mixture of polysaccharides (carrageenan), possibly by acting as immunomodulator of the inflammatory response.