Free Radicals: Health Implications and their Mitigation by Herbals

Free radicals pose a serious threat to tissues and vital organs, especially membrane lipids, proteins and nucleic acids of cells. Overproduction of reactive oxygen/ nitrogen species (ROS/RNS) and other related radicals lead to oxidative stress which has been implicated in aging and a number of diseases. Free radicals react with biomolecules and cause lipid peroxidation, loss of enzyme activity, mutation and carcinogenesis. A number of degenerative diseases including cardiovascular disease, diabetes, and adverse hepatic conditions have been attributed to accumulation of free radicals. Diseases resulting from radical overload might also lead to different types of cancers. However free radicals at low or moderate levels are vital to human health. ROS and RNS produced in a well regulated manner help maintain homeostasis at the cellular level in the normal healthy tissues and play an important role as signaling molecules. Cellular antioxidant enzyme systems including superoxide dismutase, catalase, glutathione peroxidases/reductase, peroxiredoxins along with non enzymatic antioxidants viz., tocopherols, vitamin C and glutathione etc., apart from several dietary components protect cells and organisms from the lethal effects of excessive ROS production. Natural products of plant origin have been used in traditional medicine for the treatment of diseases resulting from radical overload. The diversity of phytochemicals such as polyphenols, flavonoids, carotenes and saponins etc. present in plants and dietary components provide drug leads for the development of novel therapeutic agents. This review deals with the components of free radical biology, their adverse consequences in humans and amelioration of diseases by botanical therapeutics.