Free radicals

Free Radicals are molecules with an unpaired electron. They are generated in our body by various endogenous systems, exposure to different physicochemical conditions or pathophysiological states. At low levels, free radicals exert beneficial effects while at high concentrations, they generate oxidative stress and damage all cell structures. This review deals with the sources of the free radicals, their beneficial and deleterious effects on cellular activities; it highlights the role of free radicals and oxidative stress in various physiological states like cancer, cardiovascular diseases, Alzheimer’s disease, kidney disease, etc. The harmful effect of free radicals is neutralized by antioxidants, which prevents oxidative damage by reacting with free radicals. Therefore, the best remedy is to increase the intake of natural antioxidant.

One of the hallmarks of oral cancer is its inherent insensitivity to Radiotherapy. We have analysed the tumor metabolites and quantization of biochemical and bioenergetic metabolites by NMR spectroscopic analysis. In this study, trace element selenium exhibit dual nature in oxic and hypoxic conditions as an antioxidant and anticarcinogen respectively, indexing its radiosensitising effect, denoting a remarkable decrease in tumor mass with the gradual disappearance of tumor characteristics and oxidative stress in oral cancer cases undergoing radiotherapy. Dual role of selenium as a radio sensitizer and radio-protector could warrant a significant progress in the cancer patients, as an adjuvant to the conventional therapies in oral cancer management. Key words: Selenium, Free radicals, Oral cancer, Radiosensitisation, Radiotherapy. 

Constant production of unstable molecules in the body beyond a limit result in severe damage of cell proteins, DNA, lipids etc. These set of species are free radicals which try to acquire stable configuration by snatching away the electrons from the surrounding molecules thereby resulting in a chain reaction. This leads to oxidative stress which is a starting point for various life threatening diseases. Coloured Petri-Net (CPN) on the other hand is a modelling tool which is suited and used for synchronization, concurrency and message passing as it is a graphical modelling language. This paper presents a modelling set up of reactions caused by free radicals using CPN tool.