Quantitative Determination of α-Arbutin, β-Arbutin and Hydroquinone from Viburnum, Arctostaphylos, Vaccinium, Pyrus and Ilex Species by HPLC-UV Method
Arbutin is a hydroquinone derivative with a glucose moiety at the para-position of a phenol molecule. β-Arbutin, in which the hydroxyl group at C-1 of glucose is equatorial, is commonly found in species of several plant families in nature ; α-arbutin (with axial orientation of the hydroxyl group at C-1 of glucose) is a biosynthetic or biotransformed isomer of β-arbutin. In cosmetic preparations, α- and β-arbutin are widely used to lighten the skin on the basis of studies that arbutin inhibited tyrosinase activity by interacting with copper ions at the active site . However, β-arbutin can be hydrolyzed and release hydroquinone. In skin lightening applications, hydroquinone has been classified as unsafe for topical use because of high incidence of ochronosis and leukomelanoderma, and it has been banned for this use in the European Union.
With the objective of determining the occurrence of α-arbutin in nature and comparison of arbutin contents in different plant parts from the same species, a method for the quantitative determination of α-arbutin, β-arbutin and hydroquinone in different plants from various genera Viburnum, Arctostaphylos, Vaccinium, Pyrus and Ilex was developed using HPLC-UV. The separation was achieved by using reverse phase C-18 column material with a gradient system composed of water and methanol, both containing acetic acid. The column temperature was maintained at 45 °C. The method was validated for solvents of sample preparation, linearity, repeatability, limits of detection (LOD) and limits of quantification (LOQ). From 50 species of the genus Viburnum, Arctostaphylos, Vaccinium, Pyrus and Ilex, a total 78 plant samples were analyzed, and the contents of arbutin and hydroquinone in these samples were quantitated.
Acknowledgements: This research is supported in part by “Science Based Authentication of Dietary Supplements” funded by the Food and Drug Administration grant number 5U01FD004246, the United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No. 58 – 6408 – 02 – 1-612. References:  Lukas B, Schmiderer C, et al. (2010) Food Chem, 121: 185 – 190.  Lin JW, Chiang HM, et al. (2008) J Food Drug Anal, 16: 1 – 10.