Inhibition of Mushroom Tyrosinase by Kojic Acid Octanoates

Abstract

Octanoic acid 2-hydroxymethyl-4-oxo-4//-pyran-5-yl ester (kojic acid 5-O-capryloate, 2), octanoic acid 4-oxo-2-(l-oxooctyloxymethyl)-4//-pyran-5-yl ester (kojic acid 5,7-di-O-dicapryloate, 3), and octanoic acid (5-hydroxy-4-oxo-4//-pyran-2-yl)-methyl ester (kojic acid 7-O-capryloate. 5) were prepared from 5-hydroxy-2-hydroxymethyl-4//-4-pyrone (kojic acid, 1) and caprylic acid. We also describe the synthesis of 11-aminoundecanoic acid (5-hydroxy-4-oxo-4//-pyran-2-yl)-methyl ester (6 ). In solution, the monoesters are non-competitive in hibitors of mushroom tyrosinase (EC 1.14.18.1) (2: IC50 = 107 jiM, 5: IC5 0 = 15 jam, 6 : IC50 = 20 [.im; cf. 1: IC50 = 45 [.im, mixed type inhibition). When tyrosinase is immobilized in a polyvinylalcohol membrane, 5 is a weaker inhibitor than 1 or 2.

Optimisation and Characterisation of Lipase-Catalysed Synthesis of a Kojic Monooleate Ester in a Solvent-Free System by Response Surface Methodology

“…cepacia in organic solvent. Moreover, the hydroxyl group at the C-5 position of kojic acid can also esterified when a chemical catalyst is used [ 24 ]. In order to confirm which hydroxyl group esterified, S3 Fig shows the two-dimensional COSY spectrum which to determine the connectivity of kojic acid and palm-based oleic acid structure by determining which protons and carbons is spin-spin coupled.…”

Incorporation of Kojic Acid-Azo Dyes on TiO2 Thin Films for Dye Sensitized Solar Cells Applications

“…The presences of four doublets peaks at 8.19-7.13 ppm were attributed to eight protons in aromatic ring. The peak of oxymethyl proton of was observed at 5.26-5.24 ppm as singlet indicated 7-Osubstituent [36] vinyl chain resonated as doublet at 4.16-4.06 ppm as triplet. The 13 C NMR spectra showed all the important peaks supported to the formation of the desired product.…”

Determination of phenolic compounds using recombinant tyrosinase from Streptomyces antibioticus

“…Summarisation of this principle of enzymatic substrate regeneration leads not only to an increase in sensitivity but also to an increase in stability of the biosensor, because almost no polymeric products are accumulated. Enzymatic substrate recycling has also been used in combination with immunoassays [9] and it has been applied in inhibitor studies [10].…”