Novel hydroxypyridinone derivatives containing an oxime ether moiety: Synthesis, inhibition on mushroom tyrosinase and application in anti-browning of fresh-cut apples

Abstract

A range of hydroxypyridinone derivatives were synthesized starting from kojic acid. Among them, 10 and 11 were found to possess the strongest inhibitory effect on monophenolase activity of mushroom tyrosinase, having IC values of 2.04 and 1.60μM, respectively. The IC values of 10 and 11 for the inhibition of diphenolase activity of mushroom tyrosinase were determined as 13.89 and 7.99μM, respectively. Investigation of the inhibitory mechanism of these two compounds indicated that the inhibition was reversible and of a competitive-uncompetitive mixed type. The K and K values of 10 were determined to be 24.84 and 32.54μM, respectively, and the corresponding values for 11 being 18.07 and 21.34μM, respectively. The effect of 11 on the browning process of fresh-cut apples was evaluated by measuring the color change and browning index. The results indicated that 11 had a significant effect on controlling the browning of fresh-cut apple slices.

Exploring the phytochemical profile of Cytinus hypocistis (L.) L. as a source of health-promoting biomolecules behind its in vitro bioactive and enzyme inhibitory properties

“…Tyrosinase catalyses the oxidation of phenolic compounds to the corresponding quinones and is responsible for the enzymatic browning of fruits and vegetables, which display a characteristic undesirable colour and flavour. The oxidation products of phenolic compounds can then react with other food components, including amines, peptides, and proteins, which further reduces food quality and digestibility (Shao et al, 2018). Tyrosinase also plays a critical role in the biosynthesis of melanin and its over-activity can cause skin hyperpigmentation (Niu and Aisa, 2017).…”

Functionality study of chalcone-hydroxypyridinone hybrids as tyrosinase inhibitors and influence on anti-tyrosinase activity

“…Monophenolase and diphenolase activity was measured as described previously by monitoring the dopachrome absorbance at 475 nm 17 . L-Tyrosine and L-DOPA were used as reaction substrate for monophenolase and diphenolase assays, respectively.…”

“…Molecular docking was performed by using CDOCKER module embedded in Discovery Studio 2.5 software (Accelrys Software, Inc., San Diego, CA, USA) 17 . The X-ray crystal structure of tyrosinase from Agaricus bisporus (PDB ID: 2Y9X) was retrieved from the Protein Data Bank (http://www.rcsb.org/pdb).…”

“…Kojic acid, a secondary metabolite produced by Aspergillus and Penicillium moulds, provides a promising starting point for the synthesis of new tyrosinase inhibitors; the a-hydroxy ketone functionality plays an important role in tyrosinase inhibition 14,15 . Based on previous results, relating to hydroxypyridinones [16][17][18][19] , we have functionalised kojic acid to form new derivatives in attempt to identify more potent tyrosinase inhibitors.…”

Enzymatic characteristics of polyphenoloxidase from shrimp (Penaeus vannamei) and its inhibition by a novel hydroxypyridinone derivative

“…Indeed, it has been demonstrated that some hydroxypyridinone derivatives effectively retard the browning of shrimp (Dai et al, 2016). Recently, a range of hydroxypyridinone derivatives containing an oxime ether moiety have been synthesized starting from kojic acid in our laboratory (Shao et al, 2018). Among them, 5-hydroxy-1-octyl-4-oxo-1,4-dihydropyridine-2-carbaldehyde O-ethyl oxime (1, Fig.…”