RESUMEN
2-(4-Fluorophenyl)-quinazolin-4(3H)-one (FQ) was synthesized, and its structure was identified with (1)H nuclear magnetic resonance ((1)H NMR), (13)C nuclear magnetic resonance ((13)C NMR), fourier transform infrared spectroscopy (FTIR), and high resolution mass spectrometry (HRMS). From the enzyme analysis, the results showed that it could inhibit the diphenolase activity of tyrosinase (IC50=120±2µM). Furthermore, the results of kinetic studies showed that the compound was a reversible mixed-type inhibitor, and that the inhibition constants were determined to be 703.2 (KI) and 222.1µM (KIS). The results of fluorescence quenching experiment showed that the compound could interact with tyrosinase and the substrates (tyrosine and l-DOPA). Molecular docking analysis revealed that the mass transfer rate was affected by FQ blocking the enzyme catalytic center. In brief, current study identified a novel tyrosinase inhibitor which deserved further study for hyperpigmentation drugs.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Monofenol Monooxigenasa/antagonistas & inhibidores , Quinazolinonas/química , Quinazolinonas/farmacología , Streptomyces/enzimología , Halogenación , Cinética , Levodopa/metabolismo , Simulación del Acoplamiento Molecular , Monofenol Monooxigenasa/metabolismo , Tirosina/metabolismoRESUMEN
The objective of this study was to assess the structure, anti-tyrosinase activity, and mechanism of proanthocyanidins extracted from Rhododendron pulchrum leaves. Results obtained from mass spectra of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS) revealed that proanthocyanidins were complex mixtures of procyanidins, prodelphinidins, propelargonidins, and their derivatives, among which procyanidins were the main components. The anti-tyrosinase analysis results indicated that the mixtures were reversible and mixed competitive inhibitors of tyrosinase. Interactions between proanthocyanidins with substrate (L-tyrosine and 3,4-dihydroxyphenylalanine) and with copper ions were the important molecular mechanisms for explaining their efficient inhibition. This research would provide scientific evidence for the use of R. pulchrum leaf proanthocyanidins as new novel tyrosinase inhibitors.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Monofenol Monooxigenasa/antagonistas & inhibidores , Hojas de la Planta/química , Proantocianidinas/química , Proantocianidinas/farmacología , Rhododendron/química , Agaricales/enzimología , Cobre/farmacología , Interacciones Farmacológicas , Inhibidores Enzimáticos/aislamiento & purificación , Inhibidores Enzimáticos/metabolismo , Simulación del Acoplamiento Molecular , Monofenol Monooxigenasa/metabolismo , Proantocianidinas/aislamiento & purificación , Proantocianidinas/metabolismoRESUMEN
Proanthocyanidins were purified from avocado (Persea americana) fruit, and their structures were analyzed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and high-performance liquid chromatography-electrospray ionization-QTRAP mass spectrometry (HPLC-ESI-QTRAP MS) techniques. The results obtained from mass spectrometry (MS) analysis demonstrated that the proanthocyanidins were homo- and heteropolymers of procyanidins, prodelphinidins, propelargonidins, and procyanidin gallate. From the enzyme analysis, the results showed that they could inhibit the monophenolase and diphenolase activities of tyrosinase. The inhibition mechanism of the proanthocyanidins on the enzyme was further studied, and the results indicated that they were reversible and competitive inhibitors. Finally, the results acquired from molecular docking, fluorescence quenching, and copper ion interacting tests revealed that adjacent hydroxyl groups on the B ring of proanthocyanidins could chelate the dicopper catalytic center of the enzyme. In addtion, proanthocyanidins were proven to be an efficient quencher of substrates. This study would lay a scientific foundation for their use in agriculture, food, and nutrition industries.