Flavonoids, a group of naturally occurring antioxidants and metal chelators, can be used as tyrosinase inhibitors due to their formation of copper-flavonoid complexes. Thus, to investigate the underlying inhibition mechanism, a large group of flavonoids from several major flavones and flavonols were tested using fluorescence quenching spectroscopy. In addition, large differences in the tyrosina...

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, ...

Caseins were crosslinked by Trichoderma reesei tyrosinase in both raw and heat-treated skim milk. Tyrosinaseinduced crosslinking was beneficial in the preparation of acidified milk gels from raw milk, but it did not have an effect on acid gels made from heat-treated milk INTRODUCTION Enzymes that form covalent bonds between or within proteins are potential tools in improving the texture of dair...

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 ...

Non-toxic natural products employed in the formulation of cosmetics are of considerable interest. Recent efforts have focused on the identification of substances that inhibit tyrosinase activity (skin whitening properties) or suppress the formation of reactive oxygen species in skin cells (antiaging). In the present study, different parts of Ixora coccinea (IC) in various solvents were examined...

Avocado (Persea americana Mill.) is a member of Lauraceae with one-seeded berry fruit and cultivated in all tropical, subtropical regions the world Southern coast region Turkey. Oxidative damage caused by UV can trigger inflammation, resulting serious inflammatory skin diseases including eczema, seborrheic dermatitis, hyperpigmentation ageing. Enzyme inhibitors involved melanogenesis, such as t...

We have undertaken the purification of mushroom tyrosinase to obtain homogeneous enzyme for a study of its mechanism, which is unknown. Purified mushroom tyrosinases have already been reported (l-9). Some of these preparations were homogeneous, or almost homogeneous, by either electrophoresis or ultracentrifugation; one was homogeneous by both criteria (3, 9). However, there are discrepancies a...

Preparation and characterization of cross linked amine-functionalized magnetic nanoparticles as an appropriate support for covalent immobilization on tyrosinase was presented in the study "Covalent immobilization of tyrosinase onto cyanuric chloride crosslinked amine-functionalized superparamagnetic nanoparticles: synthesis and characterization of the recyclable nanobiocatalyst" (Abdollahi et a...

This study compared the total flavonoid content of Glycyrrhiza glabra L. leaf and root extracts. Results suggested that the total flavonoid content in the leaf extract was obviously higher than that in the root extract. Pinocembrin, the main compound in the leaf extract after purification by column chromatography, showed good antioxidant activity and nitrite scavenging capacity, but moderate in...

Herbal nanoparticles gain lot of attention because of their pharmaceutical importance. The present study reports the eco-friendly synthesis, characterization and their tyrosinase activity of silver nanoparticles (AgNPs) using aqueous extract of Bidens frondosa. The appearance of brown color indicated the formation of B. frondosa AgNPs. The Formation of AgNPs was confirmed by UV–Vis spectroscopy...