layer of the dermis and is the major cellular component responsible for skin color. Although normal melanin pigmentation in the skin is the major defense mechanism against ultraviolet light, the production of abnormal pigmentation such as melasma, freckles, senile lentigines, and other forms of melanin hyperpigmentation can be a serious problem aesthetically. The novo synthesis of melanin invol...

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...

Proteasomes are multicatalytic proteinase complexes within cells that selectively degrade ubiquitinated proteins. We have recently demonstrated that fatty acids, major components of cell membranes, are able to regulate the proteasomal degradation of tyrosinase, a critical enzyme required for melanin biosynthesis, in contrasting manners by relative increases or decreases in the ubiquitinated tyr...

ABSTRACT The related structure–activity relationships of cinnamic acid and its derivates have not been studied in details yet. Herein, antityrosinase antioxidant activities 18 compounds were evaluated. results demonstrated that the substituents on phenyl ring led to enhancement inhibition monophenolase weakening diphenolase. Among these tested compounds, 9 was first discovered as a tyrosinase i...

Cutaneous hyperpigmentation is a common disorder due to excess melanin production by the enzyme tyrosinase. The gold standard for treatment is hydroquinone (HQ), which reduces pigmentation through its toxicity to melanocytes rather than via tyrosinase inhibition. We screened an internal library for oligopeptides that inhibited both mushroom and human tyrosinase but showed no cytotoxicity to hum...

To assay the in vitro xanthine oxidase and Tyrosinase inhibitory activity of the alkaloid fractions of the leaves of Indigofera spalathoides and to determine its enzyme inhibition mechanism. Xanthine oxidase and Tyrosinase inhibitory activity was assayed spectrophotometrically under aerobic conditions and the degree of enzyme inhibition was determined by measuring the increase in absorbance at ...

The present study was focused on improving the quality of rice koji by fermentation with a selected Aspergillus oryzae strain and a plant Astragalus radix. A. oryzae KCCM 60345 was used as main inoculant and the Astragalus radix was added as supplement in rice koji preparation. LC-MS based metabolite analysis and tyrosinase inhibitory activities were studied for different time periods. A. oryza...

The twigs of Morus alba L. were found to show strong tyrosinase inhibition activity, and the responsible active components in the extract were further investigated in this study. A flavone, named morusone (1), and sixteen known compounds 2-17 were isolated from M. alba twigs and their structures were identified by interpretation of the corresponding ESI-MS and NMR spectral data. In the tyrosina...

A series of hydroxy- or methoxy-substituted phenylmethylenethiosemicarbazones were designed, synthesized and evaluated as mushroom tyrosinase inhibitors. The results demonstrated that most of target compounds had remarkable inhibitory activities on mushroom tyrosinase. Interestingly, compound 2h was found to be the most potent tyrosinase inhibitor with IC50 value of 0.18 microM. The possible in...

Tea contains polyphenols and is one of the most popular beverages consumed worldwide. Because most tyrosinase inhibitors that regulate melanogenesis are phenol/catechol derivatives, this study investigated the inhibitory effects of Camellia sinensis water extracts (CSWEs), including black tea, green tea, and white tea extracts, on melanogenesis using immortalized melanocytes. CSWEs inhibited me...