Infusions of Indian black tea (BTI), when administered orally, produced significant inhibition of rat paw oedema, induced with carrageenin (pre and post treatment) and arachidonic acid. BTI was also found to inhibit peritoneal capillary permeability and caused a marked reduction of lipopolysaccharide induced PGE(2) generation. In these models, the observed antioedema effect was similar to that of BW755C (a dual inhibitor of cyclooxygenase and 5-lipoxygenase enzymes). BTI was found to scavenge superoxide and hydroxyl radicals, and also protected rat erythrocytes from the damaging effects of hydrogen peroxide. In chronic studies, BTI inhibited granuloma formation along with the reduction of both lipid peroxidation and hydroxyproline content (in the granuloma tissue). Significant antiarthritic activity was observed with regular administration of BTI in the Freund's adjuvant induced model of arthritis. Chronic treatment with BTI (in arthritic rats) resulted in a decrease of paw diameter and tissue lipid peroxidation, along with a restoration of GSH, catalase and superoxide dismutase levels.
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