Hyperpigmentant activity of leaves and flowers extracts of Pyrostegia venusta on murine B16F10 melanoma.

Pyrostegia venusta is a native Brazilian plant which has a variety of uses in traditional folk medicine including the treatment of vitiligo. However, its effectiveness on melanogenesis is not yet elucidated. This study aimed to investigate the melanogenic activity of hydroalcoholic extracts from the leaves and flowers of P. venusta on murine B16F10 melanoma cells. Different concentrations of the hydroalcoholic extracts of flowers and leaves of P. venusta were evaluated in trials of spontaneous melanin content (4 days), and cell viability by the MTT assay in murine B16F10 cells, and in the mushroom tyrosinase activity in vitro. Both extracts, leaves (0.1; 0.3; 1 and 3 μg/mL) and flowers (0.03 and 0.1 μg/mL) increased the melanin content in a concentration dependent manner after 4 days of incubation on melanoma cells. Leaves extract promoted enhancement of melanogenesis with maximum effect of 33.3±3% (3 μg/mL), and the flower extract increased in 23.4±3% (0.1 μg/mL). The cell viability test using MTT showed that in the same tested concentrations of both extracts no cell death was detected. Actually, either extract was not able to cause any change in the tyrosinase activity. HPLC analysis of P. venusta extracts found 0.09% and 1.08% of allantoin on leaves and flowers extracts, respectively. The leaves and flowers extracts of P. venusta stimulates B16F10 melanogenesis at very low concentrations. These findings support the folk medicinal use of P. venusta on the treatment of hypopigmentation diseases, such as vitiligo.