Black mulberry extract aka blackberry contains arbutin, so it may be able to prevent melanin production. Unforunately, there’s limited research supporting this, and only in vitro studies, not on skin. Further study is needed.
eMedicine Journal, November 5, 2001, volume 2, number 11, www.emedicine.com
Biophysical Research Communications, volume 243, number 3, pages 801–803