Antioxidants neutralize free radicals produced by various environmental insults such as ultraviolet radiation, cigarette smoke, and air pollutants, thereby preventing cellular damage. The role of oxidative stress and antioxidants is known in diseases like obesity, atherosclerosis, and Alzheimer’s disease.
Aging is a process of a progressive decrease in the functioning and reserve capacity of all organs in the body, including the skin (intrinsic or chronological aging). This naturally occurring functional decline in the skin is often compounded and accelerated by chronic environmental insults such as ultraviolet radiation, pollutants, smoking, etc., (extrinsic aging).
SKIN AND FREE RADICALS
In healthy skin, practically all types of skin cells produce reactive oxygen (ROS) and reactive nitrogen (RNS) species. These free radicals are indispensable effectors in the homeostatic pathways leading to cell proliferation, differentiation, senescence, and death. An elaborate network of endogenous antioxidants maintains homeostasis by neutralizing these free radicals from causing damage to cells. When this fine balance between free radicals and endogenous antioxidants is lost, it results in a phenomenon called oxidative stress. Chronic oxidative stress has been suggested as being the cause or consequence of many acute and chronic human diseases e.g. obesity, cardiovascular diseases, cancer, acute lung injury, retinal degeneration, Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Oxidative stress also plays a role in various dermatological disorders like the aging of skin e.g., solar elastosis, deep wrinkles, coarse texture, telangiectasia and pigmentation, psoriasis, allergic contact dermatitis, atopic dermatitis, vitiligo, acne vulgaris, pemphigus Vulgaris (PV), lichen planus, alopecia areata, and melanomas.
Various pathogenic mechanisms are responsible for these lesions such as induction of transcription factors that includes Activator protein (AP-1) and Nuclear factor κB (NF-κB) which are responsible for inflammatory changes, metalloproteinase (MMP) like collagenase which causes decreased collagen production, increased collagen breakdown, and increased elastin accumulation resulting in features of aging and lastly mitogenic activated protein kinase (MAPK), which is one of the factors responsible for skin cancers.
Antioxidants are those molecules which are capable of inhibiting the oxidation of other molecules. Oxidation is a process where there is the loss of electrons or an increase in oxidation state by a molecule, atom or ion.
As the number of molecules having antioxidant properties is increasing with each passing day, it is difficult to keep abreast of all of them. Commonly used antioxidants in dermatology are classified as endogenous and exogenous