• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.193-200
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• 1996

In eastern Asian region, cosmetic preparations containing the molecues possessing the whitening activity are promising. In this study, 100 plant extracts were screened in order to elucidate the whitening effects using in vitro tyrosinase assay and DOPA autooxidation. Several plant extracts such as Morus alba, Glycyrrhiza glabra showed the inhibitory activity (>50%) against mushroom tyrosinase at the concentration 333$mu extrm{m}$/ml. And plant extracts including Morus alba and Bupleurum falcatum showed the inhibitory activity (>50%) at the concentration of 500($\mu\textrm{g}$/ml against DOPA autooxidation. The IC50 values of the several extracts were also found.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.409-414
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• 1995

Antioxidative characteristics of dihydroxyphenylalalnine(DOPA), melanin and enzymatic oxidation products of tyrosine(EOPTs) were studied in a model system. EOPTs were prepared by the tyrosine-tyrosinase reaction at pH 6.5 and $25^{\circ}C$ at various time intervals(0~120min). All EOPTs were brown in varied intensities with increased absorption at 200~210, 280, 310~320nm, and 450~490nm. EOPTs obtaiend at the early stage of the reaction(1~3min especially) showed a higher antioxidative activity than those from the later stage on the inhibition of peroxide, conjugated dienoic acid and malonaldehyde formations in linoleic acid autoxidation. Additionally among the substances of tyrosine, DOPA and melanin, DOPA showed the highest antioxidative activity while that of tyrosine was the lowest during the linoleic acid autooxidation. It was observed that DOPA and melanin had the ability of free radical scavenging, which may party contribute to their antioxidative activity.