Cell-permeable. An Antioxidant, anti-inflammatory and immunosuppressive agent. Suppresses LPS-induced cytokine release in macrophages and monocytes (IC50 = 40 nM for IL-1β and IL-1α, 80 nM for IL-6, 110 nM for prostaglandin E2 and 210 nM for IL-8 and TNF-α). Suppresses nitric oxide (NO) production (IC50 = 230 nM) and LPS-induced NF-κB activation (IC50 = 270 nM). Inhibits chymotrypsin-like activity of 20S proteasome (IC50 = 2.5 µM) and lipid peroxidation induced by ADP and Fe²⁺ in rat liver mitochondria (IC50 = 7 µM).