A melanocyte cell culture model to assess the ability of two botanicals to stimulate melanization and provide protection from UVB irradiation

This study assessed the effect and mechanism of action of 2 botanical extracts with respect to their ability to promote skin pigmentation by establishing pure cultures of melanocytes from neonatal foreskin. Melanocyte cultures were treated with test botanicals in a dose-dependent, time-response manner. Melanocytes were then assessed for viability of culture, melanin content, protein content, tyrosine hydroxylase activity, and change in cell morphology. To assess the ability of selected botanicals to protect melanocytes from exposure to ultraviolet radiation, treated cells were exposed to ultraviolet B radiation and assayed for cell death via cell count using a Coulter counter. Of the 2 botanicals studied, Angelica acutiloba inconsistently altered melanocyte morphology. An increase in dendrite number was observed when different cell lines were observed under light microscopy. This effect did not occur for every cell line treated with Angelica. Another botanical, Cassia tora, was found to be melanogenic. The increase in melanin did not provide protection to treated melanocytes when exposed to ultraviolet B irradiation. Melanocytes in cell media supplemented with 0.2mM L-tyrosine were more sensitive to ultraviolet B irradiation as determined by cell count postexposure. Melanocytes in media supplemented with 0.2 mM L-tyrosine and 80 uM forskolin, a known photoprotective, only provided moderate photoprotection to melanocytes.;The findings in this research may have significance for individuals who are taking health supplements high in tyrosine or for people who maintain a diet with high tyrosine content.