Reactive radicals of nitrogen (nitric oxide and derivatives such as peroxynitrite) and of oxygen (superoxide anion, hydrogen peroxide, hydroxyl radical) can inflict considerable damage on macromolecules (proteins, nucleic acids, complex lipids), give rise to carcinogens (e.g., nitrosamines), and trigger (or sometimes prevent) apoptotic death of cells such as macrophages and vascular epithelial cells. There are mechanisms for scavenging and antagonizing those highly reactive species of molecules and for repairing damage caused by them. (more…)

Aging in human is a combination of two ageing processes: development or maturation, and senescence aging or decline. Development or maturation is the positive aspect of aging; humans typically acquire greater wisdom, experience, and expertise in specific fields as they grow older. Senescence aging, on the other hand, (more…)