Role of free radicals in human inflammatory diseases

The role of free radicals can be found in the inflammatory process which is a complex process resulting many human diseases. Inflammations are mainly divided into acute and chronic inflammation depending on various inflammatory processes and cellular mechanisms. In recent years, there has been a great deal of attention to the field of free radical chemistry. Free radicals such as reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated by our body by various endogenous systems, exposure to different physiochemical conditions or pathological states. The purpose of the present review is to mention the role of free radical formation in the most common inflammatory processes in animals. Continued oxidative stress can lead to chronic inflammation, which in turn could mediate the most chronic diseases including cancer, diabetes, cardiovascular, neurological, and pulmonary diseases. ROS and RNS are well recognized for playing role as deleterious species. ROS and RNS are normally generated by tightly regulated enzymes, such as NO synthase (NOS) and NAD(P)H oxidase isoforms, respectively. The detrimental effect of free radicals causing health damages is termed oxidative stress and nitrosative stress. Overproduction of ROS results in oxidative stress, a deleterious process that can damage cell structures, including lipids, proteins, and DNA.