Glutathione S-transferase (GST) and multidrug resistance-associated proteins (MRPs) play major roles in drug resistance in melanoma. In this study, we investigated caffeic acid phenethyl ester (CAPE) as a selective GST inhibitor in the presence of tyrosinase, which is abundant in melanoma cells. Tyrosinase bioactivates CAPE to an o-quinone, which reacts with glutathione to form CAPE-SG conjugat...

The catalytic oxidation of catechol by crude preparations of mushroom tyrosinase was studied by a method yielding data on initial reaction velocities. Graphical analysis of the results suggests that an excess of catechol inhibits its own oxidation by a competitive process, thus accounting for the observed optimum in the substrate concentration. However, added phenol, though itself a substrate, ...

Recently, as the anti-aging role of melanin in skin and inhibition production has been identified, development materials capable maintaining homeostasis attracting attention. In this study, we further investigated anti-melanogenic effect Codonopsis pilosula extract (CPE) and, under oxidative stress, cytoprotective Melan-a melanocytes exposed to H2O2. First, CPE treatment significantly reduced b...

The apple is the most widely used fruit globally. Apples are more prone to fungal spoilage, which leads browning and subsequent changes in their flavor texture. Browning also caused by tyrosinase enzyme. By inhibiting initiation spoilage fruits, natural texture of fruits can be maintained. Biogenic NPs act as antioxidants inhibit due oxidative stress, it catalyzes deformation hyphae spores. Nan...

polyphenol oxidase (ppo), also known as tyrosinase (ec 1.14.18.1), is a copper-containing enzyme widely distributed in microorganisms, animals, and plants. this enzyme is responsible not only for browning in plants but also for melanization in animals. thus, tyrosinase inhibitors have a huge impact on industry and the economy. in the current study, we first purified the enzyme, then evaluated i...

Diacylglycerol (DAG) increases the melanin content of human melanocytes in vitro and increases the pigmentation of guinea pig skin in vivo, but the mechanism(s) underlying those effects remain unknown. In this study, we characterized the role of diacylglycerol kinase (DGK), which phosphorylates DAG to generate phosphatidic acid, in the regulation of pigmentation. Ten isoforms of DGK have been i...

In Vitro Studies on the Depigmenting Activity of 4-(p-Hydroxyphenyl)-2-Butanone: Yoshiharu FUKUDA, et al. Department of Public Health, Kumamoto University School of Medicine—The aim of this study is to investigate the enzymatic properties and the depigmenting activity of 4-(p-hydroxyphenyl)2-butanone (HPB) in vitro. The activity of HPB as a substrate of tyrosinase, its effect on tyrosinase enzy...

Tyrosinase is a key enzyme in melanin synthesis and widely distributed in plants and animals tissues. In mammals, this enzyme is related to pigment production, involved in wound healing, primary immune response and it can also contribute to catecholamines synthesis in the brain. Consequently, tyrosinase enzyme represents an attractive and selective target in the field of the medicine, cosmetics...

A series of E-4-(3-oxo-3-(substituted)prop-1-en-1-yl)benzoic acid derivatives (1-5) were synthesized by the Claisen-Schmidt condensation various ketones with 4-formylbenzoic acid. The anticholinesterase (AChE and BChE), tyrosinase, urease inhibition activities compounds examined. It was found that most active compound against AChE enzyme in activity 1. Compound 4 tyrosinase activity, while 3 ps...