Achillea santolina reduces serum interlukin-6 level and hyperalgesia during complete Freund's adjuvant-induced inflammation in male Wistar rats

Abstract

Immune system is involved in the etiology and pathophysiologic mechanisms of inflammation. Medicinal plants are an important source of substances which are claimed to induce non-specific immunomodulatory effects. In view of this and on account of the interleukin (IL)-6's role in inflammation and pain induction, this study investigated the effects of Achillea santolina extracts on inflammation which was induced by complete Freund's adjuvant (CFA) in male Wistar rats. Both methanolic and defatted extracts prepared from aerial parts of the plant were examined. Inflammatory symptoms such as hyperalgesia and paw edema in CFA-injected rats' paw were measured by radiant heat and plethysmometer during different stages of study respectively. Serum IL-6 level was checked by rat standard enzyme-linked immunosorbent assay specific kit. The results indicated dose-related effects of methanolic extract on paw edema, hyperalgesia and serum IL-6 level reduction in rats. Methanolic extract of A. santolina exhibited significant antihyperalgesic and anti-inflammatory effects during pretreatment and short-term treatment at dose of 200 mg/kg and there was no significant difference between 200 and 400 mg/kg doses of this extract. Defatted extract did not show significant effect on CFA-induced inflammation during different stages of treatment (P>0.05). Short-term treatment with methanolic extract at dose of 200 mg/kg was more effective than indomethacin in edema, hyperalgesia and serum IL-6 level reduction (P<0.01, P<0.01 and P<0.05 respectively). These results suggest that methanolic extract of A. santolina possesses potent anti-inflammatory and immunomodulatory activities during pretreatment and short-term administration.