2- Hydroquinone: Its bleaching properties were discovered when it was observed that colored tanners wearing rubber gloves acquired discolored areas on hands and forehands.
The studies on the cause of this effect pointed out to hydroquinone, an agent used in rubber synthesis (Parvez, 2007).
Hydroquinone is a hydroxyphenolic compound that inhibits the synthesis of melanin by inhibiting tyrosinase enzyme.