In an effort to find botanicals containing polyphenolic compounds with the capacity to inhibit
melanin biosynthesis, we identified a novel combination of Siberian larch (Larix sibirica) extract,
standardized to 80% taxifolin, and pomegranate fruit (Punica granatum) extract, containing 20%
punicalagins, that demonstrates a synergistic reduction of melanin biosynthesis in Melan-a cells.
The combination of Siberian larch and pomegranate extracts (1:1) produced a 2-fold reduction in
melanin content compared to Siberian larch or pomegranate extracts alone with no corresponding
effect on cell viability. Siberian larch and pomegranate fruit extracts inhibited expression of
melanocyte specific genes, tyrosinase (Tyr), microphthalmia transcription factor (Mitf), and
melanosome structural proteins (Pmel17 and Mart1) but did not inhibit tyrosinase enzyme
activity. These results suggest that the mechanism of inhibition of melanin biosynthesis by
Siberian larch and pomegranate extracts, alone and in combination, is through downregulation of
melanocyte specific genes and not due to inhibition of tyrosinase enzyme activity.
© 2012 Elsevier B.V. All rights reserved.