Arbutin (β-arbutin) is a hydroquinone glycoside, which is accumulated in many plant species such as bearberry (Arctostaphylos uva-ursi L.), bergenia (Bergenia spp.) and myrothamnus (Myrothamnus flabellifolia Welw.). It has been reported that arbutine inhibits the oxidation of L-tyrosine in a competitive manner catalyzed by tyrosinase which is an oxidase that catalyzes the rate-limiting step in melanin (a group of natural pigments) biosynthesis. Arbutins (α- and β-arbutins) are widely used in the cosmetic industry.

Arbutin is a glycosylated hydroquinone that has been found in Arctostaphylos plants and has diverse biological activities, including tyrosinase inhibitory, antioxidant, and anti-inflammatory properties. It inhibits human tyrosinase activity in crude tyrosinase solution isolated from human melanocytes (IC₅₀s = 5.7 and 18.9 mM using L-tyrosine and L-DOPA as substrates, respectively) as well as in intact melanocytes (IC₅₀ = 0.5 mM). Arbutin (50 μM) inhibits hemolysis induced by the free radical generator AAPH in sheep erythrocytes and inhibits AAPH-induced decreases in cell viability in cultured human skin fibroblasts when used at concentrations greater than 125 μM. In an LPS-induced rat model of acute lung injury, arbutin (50 mg/kg) prevents increases in IL-1β, IL-6, and TNF-α levels in lung tissue and serum. Formulations containing arbutin have been used in the treatment of hyperpigmentation disorders.

arbutin is used primarily for its anti-oxidant and bleaching properties. Arbutin is the active constituent of bearberry, and found in other plant sources, including wheat. It acts as a tyrosinase inhibitor by converting to hydroquinone, and thus can prevent melanin formation.