Isolation and Pharmacological Evaluation of Catechin in Allergic and Immune Disorders

Abstract

Aim & Objective: - Immunological diseases are not a disease but a mechanism which may play a role in a number of disorders like allergic asthma, allergic rhinitis, eczema, urticaria and angioedema, rheumatoid arthritis, anaphylaxis, oral allergy syndrome, coeliac disease, inflammatory bowel disease, allergic rhinitis and conjunctivitis. In view of these drawbacks of currently available synthetic drugs, it is reasoned that the screening of newer drugs from plant origin may which combine high selectivity with good efficacy and absence of side effects, could constitute a major therapeutic improvement in treatment of allergic and immunological disorders. The aim of the current study was to investigate the anti allergic activity of catechin on mast cell mediated allergic models and anti-arthritic activity of catechin on freund’s complete adjuvant induced arthritis models in animals. Materials & Methods:- Isolation of catechin from acacia catechu was carried out and phytochemical analysis was carried out by HPTLC for determination of presence of catechin. BALB/c mice of either sex and wistar rat were divided in four groups: normal Control, disease control, control treated with catechin (100 mg/kg, p.o), disease treated with catechin (100 mg/kg, p.o). Allergic asthma was induced by intraperitoneal injection of 50mg Ovalbumin and 4 mg aluminum hydroxide dissolved in 0.2 ml saline on days 0 and 14 in BALB/c mice. Catechin was given orally once a day from day 1 to day 35 and after which various respiratory parameters like tidal volume, respiratory rate, airflow rate, biochemical parameters like blood histamine, serum bicarbonate and nitric oxide levels, histamine release from mast cells, Bronchoalveolar lavage fluid analysis and histopathology of lungs were carried out. Rheumatoid arthritis was induced by sub plantar injection of the left hind paw with 0.1ml of complete Freund’s adjuvant. Catechin was given orally once a day from day 1 to day 21 and after which physical parameters like arthritic index, paw edema, paw thickness, splenomegaly and thymus index, biochemical and hematological parameters like C-reactive protein, serum rheumatoid factor, erythrocyte sedimentation rate and hemoglobin % and histopathology of ankle joints were carried out. Results:- Treatment of catechin to ovalbumin induced allergic animal showed significant improvement in respiratory parameters like tidal volume, respiratory rate and airflow rate as well as biochemical and hematological parameters like blood histamine, serum bicarbonate and nitric oxide levels as compared to disease control group. The treatment also showed inhibitory effects on histamine synthesis in rat peritoneal as well as bronchoalveolar mast cells as compared to disease control group. Also a significant improvement in lung histopathology was observed by treatment with catechin. Treatment of catechin to freund’s adjuvant induced arthritis showed significant improvement in physical parameters like arthritic index, paw edema, paw thickness, splenomegaly and thymus index as well as reduction of inflammatory markers like C-reactive protein, serum rheumatoid factor, erythrocyte sedimentation rate and hemoglobin % as compared to disease control group. In the disease control group ameliorative effect of catechin was observed in hyperplasia of synovium, pannus formation and destruction of the joint space. Conclusion:- From the present study we can conclude that catechin exhibited potent antiallergic activity by inhibition of histamine release from mast cells, while the study on rheumatoid arthritis suggestive that catechin have ameliorative effect by acting on immune system in experimental models of adjuvant induced arthritis.