Protective effects of TES trioleate, an inhibitor of phospholipase A2, on reactive oxygen species and UVA-induced cell damage

2-[Tris(oleoyloxymethyl)methylamino]-1-ethane sulfonic acid (TES trioleate) is an inhibitor of phospholipase A2 (PLA2), which hydrolyzes cell membrane phospholipids to produce arachidonic acid (AA) and lysophospholipids (LysoPLs). Here, we investigated the protective effects of TES trioleate on cell damage caused by ultraviolet A (UVA) light and reactive oxygen species (ROS). Pre-incubation with 250-1000 μM TES trioleate resulted in concentration-dependent protection from UVA-induced damage in HaCaT cells. Additionally, 25-1000 μM TES trioleate provided protection against H2O2 in a concentration-dependent manner. In human erythrocytes treated with 1O2, 10-100 μM TES trioleate showed concentration-dependent protective effects, similar to but stronger than the controls, 4-BPB and lipophilic antioxidant (+)-α-tocopherol at 100 μM. TES trioleate did not have detectable radical scavenging activity. Moreover, compared with (+)-α-tocopherol and rutin, TES trioleate showed low ROS scavenging activity. Thus, although TES trioleate showed cell protective effects against UVA, H2O2, and 1O2-induced damages, these effects were not caused by the scavenging ability of the radical or ROS. Finally, pretreatment of HaCaT cells and human erythrocytes with l-α-lysophosphatidylcholine produced by PLA2 promoted increased cell damage at low concentrations. Thus, the protective effects of TES trioleate on cellular damage by UVA and ROS may be associated with inhibition of PLA2-dependent cell damage rather than ROS scavenging.