The effect of ellagic acid on photodynamic therapy in leukemia cells

Ellagic acid (EA) is a naturally phenolic acid presented in different foods. It has a variety of biological activities including antioxidant, anti-inflammatory, anti-microbiological and anti-cancer properties. On account of its antioxidant activity, EA might protect cancer cells from free radical damage in photodynamic therapy (PDT) during which reactive oxygen species (ROS) production was stimulated leading to irreversible tumor cell injury. In this study, the influence of EA on K562 cells in 5-aminolevulinic acid (ALA)-based PDT is demonstrated. Cell apoptosis was assayed by flow cytometry. Oxidative damage induced by PDT was investigated by measurement of malondialdehyde (MDA). Comet assay was used to evaluate the potential genotoxic effect induced by PDT on the cells. The results showed that EA supplementation alone did not affect the lipid peroxidation, DNA damage and apoptosis in K562 cells. It increases the lipid peroxidation, DNA damage, apoptosis and decreases the survival rate in K562 cells induced by ALA-PDT. The singlet oxygen quencher sodium azide suppresses apoptosis, lipid peroxidation and DNA damage induced by EA in PDT. In conclusion, EA consumption during PDT did not decrease the effectiveness of cancer therapy on malignant cells. The effect of antioxidants on PDT maybe was determined by its sensitization ability to singlet oxygen.