OBAA is a potent phospholipase A2 (PLA2) inhibitor with an IC50 of 70 nM. OBAA blocks Melittin-induced Ca2+ influx in Trypanosoma brucei with an IC50 of 0.4 μM[2].In Vitro: OBAA (5.7 μM) induces apoptotic cell death of human umbilical vein endothelial cells (HUVEC). After 16 h of treatment, almost all of the cells had disintegrated into apoptotic bodies.In Vivo: The immunologically induced bronchospasm in guinea pigs is significantly and dose-dependently inhibited by OBAA (2.5-7 mg/kg i.v.).