Ameliorative Role of Oleuropein Extracted from Olive Leaf on Tamoxifen-Induced Hepatic 8-Hydroxydeoxyguanosine in DNA of Balb/C Mice

3 Abstract: One of the most attractive approaches to disease prevention involves the use of natural antioxidants to protect tissue against toxic injury. Tamoxifen (TAM), a medication used as anti-neoplastic drug for the treatment of breast cancer, often induces menopausal symptoms. The aim of this study was to investigate the toxicity of this drug by measuring the ability of TAM to induce oxidative DNA damage through the formation of 8-hydroxydeoxyguanosine (8-OH-dG) using HPLC with electrochemical detection as well as investigating the effect of oleuropein as antioxidant to ameliorate its toxicity. TAM initiates reactive oxygen species (ROS) formation followed by damage to DNA and other cellular compartments. Oleuropein, the phytoalexin extracted from olive leaf and proved to be a strong free radical scavenger, markedly inhibited the formation of 8-OH-dG. Results showed that oleuropein reduced the toxicity of TAM by 9 fold. These findings are consistent with conclusion that oleuropein has highly protective power against TAM toxicity and the protective action relates, at least in part to its direct free radical scavenging ability.