Use of Carnosol as a Highly Immunosuppressive Agent

Suppression of the immune responses, using products derived from medicinal plant, as a likely therapeutic measure, has become an important subject of scientific studies, recently. Rosmarinus officinalis (Lamiaceae), known as rosemary, is widely distributed in many parts of the world. The immunomodulatory effect of carnosol, a natural antioxidant derived from rosemary, was investigated using BALB/c mice. Carnosol was administered at doses of 0.04, 0.2, 0.8, 2.4 and 4 mg/kg, for 5 days. Another group of mice was treated with 20 mg cyclophosphamide/kg/day (positive control); a final group received solvent only (solvent control). Delayed-type of hypersensitivity response and hemagglutination titer were studied in these groups of animals. Results showed that three high doses of carnosol (0.8, 2.4 and 4 mg/kg) could significantly suppress both cellular and humoral activity of the immune system. Interestingly, carnosol, at doses of 2.4 and 4 mg/kg, was able to inhibit acquired immunity, higher than cyclophosphamide, which is a known potent immunosuppressant. Based on its effects, carnosol might be considered a source of drug, showing effective immunosuppression properties. Further studies should be performed on carnosol to develop an effective immunosuppressive drug or coadjuvant for the treatment of disorders caused by an exaggerated or unwanted immune response