الفهرس 
Subjects and MethodsOnly 14 pages are availabe for public view
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Abstract
Summary
Premature graying of hair is defined as graying of hair before the age of 30 years in blacks. Three processes are involved in the pathogenesis of PGH including gradual decline in the pigmentation of hairs during several cycles, loss of pigment within the anagen phase of the same hair cycle, and the emersion of the fully depigmented hair from the surface of the epidermis.
Conditions associated with generation of huge amount of ROS leading to increased oxidative stress culminating into damage to melanin producing cells, melanocytes and cause PGH. Prolonged exposure to UV rays is considered to initiate similar processes in hair follicles resulting in PGH.
The loss of antioxidative activities in graying hair bulbs and bulge regions contributes to the abnormal accumulation of hydroxyl free radicals and the resulting oxidative destruction of hair follicle melanocytes.
Prolidase activity is reported as a marker for oxidative stress for many diseases like diabetes, diabetic neuropathy, chronic liver diseases, erectile dysfunction and osteoporosis.
Human serum PON1 has lipophilic antioxidant characteristics. Paraoxonase enzyme plays a role in decreasing oxidative stress. It in particular is an important endogenous free radical scavenging system in the human body.