A dibenzocyclooctadiene with diverse biological activities; completely inhibits anti-CD3- and anti-CD28-induced release of IL-2, IL-3, IL-4, IL-6, and IFN-γ in T cells at 50 μM; reduces cell survival and UV-induced phosphorylation of p53 and Chk1 from 1-30 μM; reduces ATR kinase activity (IC50 = 7.25 μM); inhibits doxorubicin-induced lipid peroxidation, formation of DNA strand breaks, and NADPH oxidase-dependent oxygen production in mouse heart from 25-100 mg/kg; reduces the expression of p53, 3-nitrotyrosine, phosphorylated p38 MAPK and MAPKAPK-2, and MMP-2 and MMP-9; reduces tert-butylhydroperoxide-induced mortality and malondialdehyde formation and increases GSH levels and GSH-Px activity in mouse brain.