Abstract

Most of the conventional rheumatoid arthritis (RA) drugs used have severe adverse reactions. Therefore, natural plant products are continuously being sought for the management of RA. In the present study, in vitro antioxidant, joint protective and anti-inflammatory activity of aqueous green tea extract (AGTE) was evaluated in 50 patients with early RA, 30 patients with established RA and 50 healthy control subjects. All patients received 4 to 6 cups/day; 60 to 125 mg catechins of green tea for 24 weeks. The results obtained indicated that green tea possesses potent joint protective and anti-inflammatory action against RA by lowering disease activity parameters and improving COMP, HA, IL-6, and TNF-œ. The biochemical observations were supplemented with radiographic analysis of RA patients. In vitro 1,1-diphenyl-2-picryldrazil (DPPH) radical scavenging and NBT assay tests of the green tea exhibited a moderate antioxidant activity (90.3 and 87.9%) in both tests used. The possible mechanism(s) of green tea extract (AGTE) activity may be due to free radical scavenging potential caused by the presence of antioxidant component(s) in AGTE. Consequently, green tea can be used as a therapeutic regime in treatment of some RA disorders.

Key words: Cartilage oligomeric matrix protein (COMP), interluken-6 (IL-6), tumor necrosis factor (TNF-œ), rheumatoid arthritis, green tea, disease activity score (DAS)-28, pain numerical rating score (PNRS), European League Against Rheumatism Response (EULAR) criteria.

Abbreviation

RA, Rheumatoid arthritis; ECM, extracellular matrix; DAS28, disease activity score-28; PNRS, pain numerical rating score 0-10; COMP, cartilage oligomeric matrix protein; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; TNF-œ, tumor necrosis factor; Rf, rheumatoid factor; IL-6, interlukin-6; AGTE, aqueous green tea extract; EGCG, epigallocatechin-3-gallate; DPPH, 1,1-diphenyl-2-picryldrazil; NBT, nitro blue tetrazolum; EULAR, European league against rheumatism response criteria.