Final answer:
Selenium sulfide is primarily used to treat dandruff and seborrheic dermatitis, leveraging the chemical properties and health benefits of selenium, including its essential role in antioxidant enzymes like glutathione peroxidase and tissue respiration.
Step-by-step explanation:
Selenium sulfide is an active ingredient that is often used in the treatment of dandruff and seborrheic dermatitis. This compound works due to the fact that selenium, which shares similar chemical properties with sulfur, has therapeutic properties that are beneficial for skin conditions. Selenium is an essential element that, when combined with sulfur to form selenium sulfide, helps to reduce the proliferation of certain types of fungi that can cause these skin issues.
In the same family below sulfur in the periodic table, selenium exhibits a functional advantage in certain enzymes because the selenol group is more fully ionized than the thiol group at physiological pH, leading to greater catalytic activity in selenoenzymes than if cysteine were present instead of selenocysteine. Furthermore, selenium is an essential component of glutathione peroxidase, an antioxidant enzyme that protects against cellular damage from oxidation.
The health benefits of selenium also extend to playing an important role in tissue respiration, being an integral part of the biosynthesis of coenzyme Q, and providing protection against peroxidation in tissues and cell membranes.