Objectives: This study was delineated to investigate the ameliorative effect of Echinacea purpurea and curcumin against oxidative stress and immunosuppression induced by dexamethasone in rabbits.
Methods: A total of 20 healthy rabbits were used in this study and were randomly classified into 4 groups of 5 each. The 1^st group (non-treated) was served as a control, the 2^nd group intramuscularly medicated with dexamethasone (2 mg/kg) 3 times at 6 hours interval, the 3^rd group medicated with dexamethasone at the same dose then received E. purpurea (130 mg/kg) orally day after day for 21 days, and the 4^th group medicated with dexamethasone at the same dose then received curcumin (400 mg/kg) orally every day for 21 days. Blood and serum samples were collected after 1, 7, and 14 days post-dosing.
Results: Dexamethasone medicated group showed a significant decrease in WBCS, lymphocytes, neutrophils, and monocytes at the 1^st, 7^th, and 14^th day, but E. purpurea and curcumin medicated groups showed significant improvement in total and differential leucocytic count. Also, both plants showed a significant increase in lysozymes and nitric oxide against the suppressive effect of dexamethasone. Here, the dexamethasone group showed a significant decrease in serum catalase (CAT) and significant elevation in serum malondialdehyde (MDA) at 1^st and 7^th-day post-treatment. E. purpurea and curcumin groups showed a significant increase in serum CAT and significant depletion in MDA levels. Injection of dexamethasone significantly decreased the serum levels of total protein, albumin, and globulin as compared to the control group. These parameters were significantly increased after treatment with E. purpurea and curcumin. Treatment with E. purpurea or curcumin ameliorated tissue damages of liver, kidney, and spleen induced by dexamethasone.
Conclusion: Treatment with Echinacea purpurea or curcumin could ameliorate oxidative stress and immunosuppression induced by dexamethasone in rabbits.