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Melasma is an acquired hyperpigmentation disorder. Its main characteristics are bilateral irregular brown macules and patches on sun-exposed areas occurring most commonly on the face. 1 Its exact pathogenesis is not clear. However, some etiologic factors have been suggested as the major cause, such as ultraviolet radiation, hormonal alterations like those evident during pregnancy, use of oral contraceptives and other steroids, thyroid dysfunction, phototoxic drugs, ovarian tumors, use of cosmetics and photosensitizing drugs, and stressful events. 2,3 Recent investigations have demonstrated that enhanced free oxygen radicals and reactive oxygen species (ROS) have a role in the pathogenesis of many dermatoses such as lichen planus, alopecia areata, atopic dermatitis, pemphigus vulgaris, psoriasis, and vitiligo. [4][5][6][7][8] Antioxidants, either intracellular or extracellular, can inactivate the damage caused by free radicals. The intracellular antioxidants are mainly composed of free radical scavenging enzymes such as glutathione peroxidase (GPX), glutathione-S-transferase, superoxide dismutase (SOD), cytochrome oxidase, glutathione reductase, and catalase. 7,9 Two major extracellular antioxidants are bilirubin (Bil) and uric acid (UA).

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