Recent investigations of mammalian tyrosinase have shown the relationship of some chemical and physical factors to tyrosinase activity (1,2,3). Whereas the effect of temperature, pH, lyophilization, oxidation-reduction potentials, and concentrations of enzyme and substrate have been studied, the effect of different ions and ionic concentration on tyrosinase activity has not been described. Henc...

Nordihydroguaiaretic acid (NDGA), a lignan found in vegetables, fruits and legumin, has been shown to possess antineoplastic, antiviral and antioxidant characteristics. In this study, we examined the effect of NDGA on melanogenesis in human melanoma cells (HMVII). In vitro, NDGA does not alter mushroom tyrosinase activity. However, in NDGA-treated HMVII cells, cellular tyrosinase activity incre...

We compared tyrosinase cDNA sequences from a line of autosomal albino and Black Silky chickens isolated from cultured melanocytes by reverse transcription-polymerase chain reaction (RT-PCR). Both sources produce a single DNA fragment of predicted normal tyrosinase size. Direct sequencing of the PCR product showed three mutated sites in the tyrosinase gene of the albino chicken. Two silent point...

BACKGROUND Magnolia grandiflora L. flower is wildly used in Asian as a traditional herbal medication. The purpose of the study was to investigate the antimelanogenic and antioxidant properties of Magnolia grandiflora L. flower extract. In the study, the inhibitory effects of M. grandiflora L. flower extract on mushroom tyrosinase, B16F10 intracellular tyrosinase activity and melanin content wer...

Tyrosinase is a well-known key enzyme in melanin biosynthesis and its inhibitors have become increasingly important because of their potential use as hypopigmenting agents. In the present study, the anti-melanogenic effect of aqueous and ethanolic extracts from Euphorbia characias leaves, stems, and flowers in cell-free and cellular systems was examined. All the extracts showed inhibitory effec...

27 For screening of skin-whitening ingredients that modulate inhibition of melanogenesis, 28 tyrosinase promoter-based assay using a 3D spheroid culture technique is a beneficial tool to 29 improve the accuracy of raw material screening in cosmetics through mimicking of the in 30 vivo microenvironment. Although the advantages of high-throughput screening (HTS) are 31 widely known, there has bee...

Tyrosinase is the key enzyme involved in melanogenesis. The aim of this study was to investigate the in vitro inhibitory effects of gnetin C, a resveratrol dimer isolated from melinjo (Gnetum gnemon) seeds, on tyrosinase activity and melanin biosynthesis in murine B16 cells. The inhibitory activities of gnetin C and resveratrol were shown to be almost equal against tyrosinase and melanin biosyn...

Tyrosinase is an enzyme of industrial interest. The production and characterization of tyrosinase from P. sanguineus CCT-4518 were investigated. The selection of inductors, luminosity influence, inoculum size and type of culture medium on the production of tyrosinase and the effect of inhibitors on enzyme activity were performed. Optimum conditions for intracellular tyrosinase production was ob...

1. The intravenous injection of tyrosinase, a phenolic oxidase obtained from mushrooms, consistently lowers the blood pressure of rats made hypertensive by three different methods, while on the average not affecting the blood pressure of normal animals. 2. The intravenous and intramuscular injection of tyrosinase lowers blood pressure in dogs made hypertensive by the method of Goldblatt, while ...

In a previous investigation of tyrosinase activity in the cells of the nucleus substantiae nigrae of adult cats and monkeys, diphenolase, but not monophenolase activity, was detected. This is possibly due to inhibition of monophenolase. When the copper radicle in tyrosinase is oxidized, monophenolase cannot be detected, but reducing agents activate and unmask this component of tyrosinase. The e...