EFFECTS OF ROSMARINUS OFFICINALIS OIL ON HISTAMINE-INDUCED ACUTE INFLAMMATION

Rosmarinus officinalis is used widely all around the world and its extracts have shown anti-inflammatory activity. We here analyze the anti-inflammatory effects of Rosmarinus officinalis oil (RO) by estimation of its effects on the cyclooxygenase (COX) activity. We studied the activity of RO and Indomethacin in vivo and in vitro by evaluation of the COX-inhibitory potential. Male Wistar rats were treated intraperitoneally with Indomethacin (10 mg/kg bw), RO (35 and 70 mg/kg bw) and saline (0.9% NaCl). Thirty minutes after treatment the animals received a subplantar injection of Histamine (1% in saline) in the right paw and equal amount saline in the left. The changes in the rat paw volume were measured 5, 7, 15, 20, 25, 30, 60 and 120 min after the subplantar injection. The COX inhibitory activity of both agents was measured spectrophotometrically. We found a significant decrease in the paw volume in the RO treated groups (35 and 70 mg/kg bw) in comparison to Indomethacin-treated rats on the 5th, 7th and 15th min after the histamine injection (P < 0.05; n = 7). At the late phase of inflammation (30 to 120 min) similar swelling reduction was observed after treatment with Indomethacin and RO in both concentrations. The essential oil reduced the COX activity in vitro at a higher concentration in comparison to Indomethacin. IC50 of Indomethacin and RO were 0.27 +/- 0.03 mg/L and 4.70 +/- 0.45 mg/L, respectively. In conclusion, RO has anti-inflammatory effect as an Indomethacin, but the mechanism of its action especially at the early phase of inflammation is different.