feruloyltyramine and dopaquinone

Aurea Helianthus (AH), also known as wild confederate rose or golden sunflower, is a curative herb. It has been used as a medicinal material in China due to its anti-inflammatory, immune regulatory, and anti-oxidant activities. However, its melanogenic effect on skin has not been sufficiently investigated. In this study, we tested whether AH has melanogenic inhibitory activities for the development of effective skin whitening agent. The extract showed inhibition of melanin synthesis and reduced the oxidation of 3, 4-dihydroxyphenilalanine (DOPA) to o-dopaquinone. Additionally, AH downregulated the levels of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase related proteins (TRPs), suggesting that AH has inhibitory effects on melanogenesis. Analysis of the components of AH showed that it contained paprazine and trans-N-feruloyltyramine (FA). We confirmed that the effect of AH resulted from paprazine and FA. Therefore, AH might have potential as an effective candidate for skin whitening.

Topics: Animals; Antineoplastic Agents, Phytogenic; Benzoquinones; Cell Line, Tumor; Coumaric Acids; Dihydroxyphenylalanine; Down-Regulation; Helianthus; Melanins; Melanoma, Experimental; Mice; Microphthalmia-Associated Transcription Factor; Monophenol Monooxygenase; Plant Extracts; Plant Proteins; Plant Stems; Skin Lightening Preparations; Tyramine; Tyrosine

Melanin play a major role in human skin protection and their biosynthesis is vital. Due to their color, they contribute to the skin pigmentation. Tyrosinase is a key enzyme involved in the first stage of melanin synthesis, catalyzing the transformation of tyrosine to l-dopaquinone. The aim of the present study was to study molecules able to inhibit melanin synthesis through inhibition of tyrosinase and their potential use in treating pigmentation-related disorders. We targeted amides obtained from coupling p-hydroxycinnamic acid derivatives with phenylalkylamines. The biological activity was evaluated on human melanocytes by an assay which measures tyrosine-catalyzed L-Dopa oxidation. The most active amides were: trans-N-caffeoyltyramine, N-dihydrocaffeoyltyramine, and trans-N-dihydro-p-hydroxycinnamoyltyramine which induce complete inhibition at 0.1mM. At the latter concentration, kojic acid, which was used as the reference inhibitor, was inactive.

Topics: Amides; Benzoquinones; Caffeic Acids; Catalysis; Cells, Cultured; Dihydroxyphenylalanine; Enzyme Inhibitors; Humans; Levodopa; Melanins; Melanocytes; Monophenol Monooxygenase; Oxidation-Reduction; Pigmentation Disorders; Pyrones; Skin; Structure-Activity Relationship; Tyramine; Tyrosine