TNF and Arthritis: On the other hand, in a collagen-induced arthritis rat model, 50 mg/kg/day epigallocatechin gallate also showed the capacity to diminish TNF-α, IL-17, Nrf-2, and malondialdehyde levels and improve heme oxygenase-1, superoxide dismutase, catalase, and glutathione peroxidase levels [234].