arbutin brands

Molecular formula: C12H16O7

Arbutin is a hydroquinone glycoside, however the hydroquinone moiety is not solely responsible for the de-pigmentating actions of arbutin. It acts as a competitive inhibitor of tyrosinase enzyme by acting on the L-tyrosine binding site to suppress melanogenesis and mediate its de-pigmenting actions on human skin. Tyrosinase is an enzyme involved in the regulation of rate-limiting steps during the synthesis of melanin; it regulates the conversion of L-tyrosine into L-dopa, and subsequent conversion of L-dopa to L-dopaquinone. Via inhibition of tyrosinase activity in a concentration-dependent manner, arbutin attenuates the production of melanin in melanocytes. While most studies suggest that arbutin has negligible effect on the tyrosinase mRNA expression, a study assessing the effect of arbutin on melanocyte differentiation inducement system using ES cells propose that arbutin may also downregulate the expression of tyrosinase in addition to its inhibitory action on the enzyme. The contradictory findings across studies may be due to previous studies using terminally-differentiated melanocytes and melanoma cells. ...This study ... presents evidence that cotreatment of aloesin and arbutin inhibits tyrosinase activity in a synergistic manner by acting through a different action mechanism. Aloesin or arbutin similarly inhibited enzyme activity of human- and mushroom-tyrosinases with an IC50 value of 0.1 or 0.04 mM, respectively. Lineweaver-Burk plots of the enzyme kinetics data showed that aloesin inhibited tyrosinase activity noncompetitively with a Ki value of 5.3 mM, whereas arbutin did it competitively (Maeda, 1996). We then examined whether cotreatment of these agents inhibits the tyrosinase activity in a synergistic manner. The results showed that 0.01 mM aloesin in the presence of 0.03 mM arbutin inhibited activity of mushroom by 80% of the control value and the reverse was also true. The inhibitory effects were calculated to be synergistic according to the Burgi method. Taken together, we suggest that aloesin along with arbutin inhibits in synergy melanin production by combined mechanisms of noncompetitive and competitive inhibitions of tyrosinase activity.

Source: PubChem (NCBI) · compound 440936