For the first time in the present study the effects of vanillin, vanillyl alcohol, vanillic acid, as well as the newly synthesized vanillin derivative, bis-vanillin, were investigated on the oxidation of dopamine hydrochloride by mushroom tyrosinase. Among them, vanillin and bis-vanillin act as activators, while vanillyl alcohol and vanillic acid exhibited inhibitory effects, the IC50 values be...

Tyrosinase catalyzes two distinct sequential reactions in melanin biosynthesis: The hydroxylation of tyrosine to dihydroxyphenylalanine (DOPA) and the oxidation of DOPA to dopaquinone. Developing functional modulators of tyrosinase is important for therapeutic and cosmetic purposes. Given the abundance of thiourea moiety in known tyrosinase inhibitors, we studied other thiourea-containing drugs...

Stichopus japonicus has been used as a folk medicine and as an ingredient in traditional food in East Asian countries. In recent years, the bioactive compounds found in S. japonicus have been reported to possess efficacy in wound healing and may be of potential use in the cosmeceutical, pharmaceutical and biomedical industries. Although the components and their functions require further investi...

Tyrosinase catalyzes the initial, rate-limiting step of melanin synthesis; oxidative conversion L-tyrosine to L-dopa followed by L-dopaquinone means oxygen molecule. possesses bicopper active center capable utilizing molecular oxygen. Metabolic rhododendrol (RD) tyrosinase causes leukoderma in a certain population consumers. Along with cytotoxic RD metabolites, reactive species (ROS) produced d...

The aim of this study was to evaluate the effect of fluvastatin on the alpha-melanocyte-stimulating hormone-mediated increase in tyrosinase activity in the melanoma B16F10 cell line and to establish whether Akt and extracellular signal-regulated kinase (Erk) inhibition is involved in tyrosinase synthesis after fluvastatin administration. Fluvastatin modulates alpha-melanocyte-stimulating hormon...

Ecklonia cava (EC) is a brown alga that has demonstrated radical scavenging, bactericidal, tyrosinase inhibitory, and protease inhibitory activities. However, the molecular mechanisms underlying its anti-inflammatory action remain unclear. In the current study, we attempted to determine whether pretreatment with EC induces a significant inhibition of anti-inflammatory activity in lipopolysaccha...

Melanin is produced in melanocytes and stored in melanosomes. In spite of its beneficial sun-protective effect, abnormal accumulation of melanin results in esthetic problems. Hydroquinone, competing with tyrosine, is a major ingredient in topical pharmacological agents. However, frequent adverse reactions are amongst its major limitation. To solve this problem, several alternatives such as arbu...

Alleviated melanin formation in the skin through inhibition of tyrosine-tyrosinase reaction is one of the major targets of cosmetics for whitening ability. Since melanin has a pivotal role for photoprotection, there are pros and cons of inhibition of melanin formation. This study applying electron spin resonance (ESR)-spin trapping method revealed that (•)H and (•)OH are generated through tyros...

When we studied the effects of polyphenols from apple fruits on melanogenesis in B16 mouse melanoma cell lines, phloridzin had dose-dependent progressive effects on melanogenesis between 10 and 500 micrograms/ml without inhibiting cell growth. At a concentration of 500 micrograms/ml, phloridzin increased the melanin content in the cells to 181% of that in control cells. In contrast, phloretin, ...

Okadaic acid is a C38 fatty acid derivative that is known to specifically inhibit the activity of protein phosphatase 2A (PP2A). Previously, we reported that inhibition of PP2A by okadaic acid elicited extracellular signal-regulated kinase (ERK) activation, and that PP2A may be involved in melanogenesis. However, the effects of okadaic acid on melanogenesis have not been completely evaluated. I...