Antioxidants are a group of important ingredients for anti-aging skin care because of their ability to neutralize the free radical damage of cells and macromolecules (protein, DNA, lipids). – Free radical damage was one of the first processes associated with aging (See free radical theory of aging and free radical theory of skin aging). The sources of free radicals are both external and internal. The sun’s UV light generates an army of free radicals. Free radicals are both a cause and a result of inflammation

What fuels the endless burn of chronic inflammation? Oxidative stress, or free-radical damage. Because free radicals are molecules with unpaired electron and they are highly reactive oxidizing agents which gain electrons from other molecules, rendering those molecules damaged. One target of oxidative damage (free radical damage) is mitochondria the cellular organism responsible for energy production where the . Free radicals can involve (although not the only reaction) in electron chain reactions (chain redox reactions) where electrons are transferred in a sequence of redox chain reaction. One of the internal free radicals produced in our body is via our normal energy metabolism – the oxygen metabolism occurred at Mitochondria. Our normal energy (oxygen) metabolism (cellular respiration) occurs as a chain redox reaction on the cell membrane of Mitochondrion through an electron transport chain by a cascade of enzyme systems. This process results in the production of toxic by-product free radical superoxide(O2-) (termed as reactive oxygen species – ROS).This respiratory electron transport chains (ETC) on mitochondria membrane is the major sites of premature electron leakage to oxygen, thus being major sites of superoxide (O2-) production and drivers of oxidative stress. Oxidative stress damages cellular proteins, membranes (lipids, proteins) and genes (DNA) which in turn leads to systemic inflammation. Free radicals trigger and enhance inflammation and are also created during inflammation.

NF-kB is a critical compound in body protection, and in the initiation of inflammation. When it is in excess or if it is stimulated by some pathological condition, it can produce both acute and chronic inflammation. NF-kB is a ubiquitous transcription factor and regulator of numerous genes involved in the immune and inflammatory response. Reactive oxygen metabolites (free radicals) initiate and/or amplify inflammation by turning on several different genes involved in the inflammatory response via the NF-kB pathway.

Because free radicals are both a cause and a result of inflammation, there fore antioxidants not only inhibit the initiation of inflammation, but also quench the inflammation after a inflammatory response. The inflammatory response activate leukocytes and they are leaving the blood circulation and migrating to the site of the aggression (infection) where they release a large amount of ROS whose positive effect is only limited to the pathogen. Essential antioxidant vitamins such as vitamins C and E and many botanical extracts which contain potent antioxidants protects the skin from free radical-induced (chronic) inflammatory damage.