8397fa35_ening_ingredients___WHITERskin__2
[0] Alpha-Arbutin [1] Alpha-Arbutin is an epimer of arbutin (4-hydroxyphenyl alpha-glucopyranoside) [3] Melanin synthesis was reduced to 40% with 250 microg of alpha-arbutin. [4] Yes. [2] 
Inhibits tyrosinase to prevent the formation of melanin. Said to have a stronger effect than Arbutin.
List of commercial skin lightening / skin whitening ingredients | WHITERskin
2