Plant extracts have been widely used as important therapeutic drugs for many centuries all over the world. There have been many reports that natural products have various kinds of biological activities such as anti-allergy, anti-inflammatory and antimicrobial activities. Recently, the screening for the efficacy and safety of natural products has been extensively performed.

This study was carried out to find a beneficial plant extract possessing excellent antioxidative and anti-melanogenic activities. We have found that the leaf of Robinia pseudo-acacia L. has active substances which are involved in those activities.

To confirm the antioxidative activity of the extract obtained from the leaves of Robinia pseudo-acacia L., scavenging ability of the extract on DPPH free radicals and its inhibitory effects on lipid autoxidation and peroxidation were investigated. In addition, inhibitory effects of the extract on mushroom tyrosinase as well as melanin biosynthesis in cultured B16 melanoma cells were evaluated.

The acacia extract showed not only powerful antioxidative activity but also antimelanogenic acitivity as strong as that of arbutin which is a well known inhibitor of melanogenesis.

These resulis suggest that the extract from the leaves of Robinia pseudo-acacia L. could be used as a 4ghtening and antioxidative agent for the skin.