| abstract |
The present invention provides a nitric oxide production inhibitor that prevents or ameliorates facial color deterioration induced by the production of nitric oxide, and a skin external preparation suitable for improving facial color containing these. A nitric oxide production inhibitor comprising a pyrroloquinoline quinone derivative represented by the following general formula (1) and / or a pharmacologically acceptable salt thereof as an active ingredient. (1) [wherein, R1, R2, and R3 each independently represents a short-chain alkyl group, alkenyl group, aralkyl group, araryl group, phenyl group, or hydrogen atom. ] [Selection] Figure 1 |