Free radicals and other reactive oxygen species (ROS) are constantly formed in the human body. Free-radical mechanisms have been implicated in the pathology of several human diseases. Free radicals are generated physiologically during immune activation. Neopterin, an early marker of immune activation is released from monocyte-macrophages with the induction of interferon-gamma. Its biological levels are known to be increased in different types of pathologies including cancer. Neopterin is also known to be related with oxidative stress. In this study, the antioxidant effect of neopterin and silymarin, melatonin and homocystein was evaluated by NO, SO, and DPPH radicals scavenging assays. Possible cytotoxic effects of the compounds were evaluated in 3 different cell lines by MTT and LDH assays. According to the results all the compounds have the radical scavenging activities. Therefore, none of them have a significant cytotoxic potential. However, only neopterin has a significant proliferative effect at very high concentrations. The results should be confirmed and reevaluated by in vivo and in vitro experiments.
Oxidative stress is related to many pathologies and diseases including diabetes, atherosclerosis and cancer. Increase or decrease of reactive oxygen species can affect disease progression and treatment. Hence, both the development and treatment of diseases involve reactive oxygen species and antioxidants. Especially in the last decade, antioxidants became popular in the prevention of diseases and aging. Antioxidants exert their effects either by chain breaking or prevention of free radicals. In this study, the radical scavenging capacities and cytotoxic potentials of 5 non-enzymatic antioxidants were evaluated by in vitro analysis. The scavenging activities of ascorbic acid, glutathione, L-cysteine, N-acetyl-cysteine and uric acid against NO, SO, DPPH radicals were analyzed. MTT and LDH assays were performed in order to evaluate the cytotoxic activities of the compounds in HeLa, HepG2 and Hep2 cell lines. All the compounds showed comparable antioxidant activities. On the other hand, cytotoxic effect of the compound was not significant except at high concentrations. The results was approved ones again all the compounds have strong radical scavenging activity and all the antioxidants may use for treatment of inflammatory diseases.
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