Suppression of Melanin Production in a Mouse B16 Melanoma 4A5 Cell Line by a Spinach Extract

The effect of an extract of fresh and of freeze-dried spinach on the melanin production of a mouse melanoma cell line, B16 melanoma 4A5, was examined. Both the extracts of dried and fresh spinach suppressed the melanin production in B16 melanoma 4A5. The passage of the cells in the presence of 100 μg/ml of fresh spinach extract clearly reduced the melanin production. However, production was evoked again when the spinach extract was removed, and no cytotoxicity of the extract toward the cells was observed. No inhibition of mushroom tyrosinase by the extract was detected either. These results indicate that the reduction of melanogensis by spinach extract was not due to cytotoxicity toward the cells nor to the inhibition of tyrosinase activity in the cells.