19275-70-8Relevant articles and documents
Exploring 3-hydroxyflavone scaffolds as mushroom tyrosinase inhibitors: synthesis, X-ray crystallography, antimicrobial, fluorescence behaviour, structure-activity relationship and molecular modelling studies
Ashraf, Jamshaid,Mughal, Ehsan Ullah,Sadiq, Amina,Bibi, Maryam,Naeem, Nafeesa,Ali, Anser,Massadaq, Anam,Fatima, Nighat,Javid, Asif,Zafar, Muhammad Naveed,Khan, Bilal Ahmad,Nazar, Muhammad Faizan,Mumtaz, Amara,Tahir, Muhammad Nawaz,Mirzaei, Masoud
, p. 7107 - 7122 (2020/08/21)
To explore new scaffolds as tyrosinase enzyme inhibitors remain an interesting goal in the drug discovery and development. In due course and our approach to synthesize bioactive compounds, a series of varyingly substituted 3-hydroxyflavone derivatives (1-23) were synthesized in one-pot reaction and screened for in?vitro against mushroom tyrosinase enzyme. The structures of newly synthesized compounds were unambiguously corroborated by usual spectroscopic techniques (FTIR, UV-Vis, 1H-, 13C-NMR) and mass spectrometry (EI-MS). The structure of compound 15 was also characterized by X-ray diffraction analysis. Furthermore, the synthesized compounds (1-23) were evaluated for their antimicrobial potential. Biological studies exhibit pretty good activity against most of the bacterial-fungal strains and their activity is comparable to those of commercially available antibiotics i.e. Cefixime and Clotrimazole. Amongst the series, the compounds 2, 4, 5, 6, 7, 10, 11, 14 and 22 exhibited excellent inhibitory activity against tyrosinase, even better than standard compound. Remarkably, the compound 2 (IC50 = 0.280 ± 0.010 μg/ml) was found almost sixfold and derivative 5 (IC50 = 0.230 ± 0.020 μg/ml) about sevenfold more active as compared to standard Kojic acid (IC50 =1.79 ± 0.6 μg/ml). Moreover, these synthetic compounds (1-23) displayed good to moderate activities against tested bacterial and fungal strains. Their emission behavior was also investigated in order to know their potential as fluorescent probes. The molecular modelling simulations were also performed to explore their binding interactions with active sites of the tyrosinase enzyme. Limited structure-activity relationship was established to design and develop new tyrosinase inhibitors by employing 2-arylchromone as a structural core in the future. Communicated by Ramaswamy H. Sarma.
Influence of a 4′-substituent on the efficiency of flavonol-based fluorescent indicators of β-glycosidase activity
Bojarski, Piotr,Kozakiewicz, Karol,Liberek, Beata,Myszka, Henryk,Nowacki, Andrzej,Reszka, Milena,Serdiuk, Illia E.
, p. 7635 - 7648 (2020/10/14)
This article presents novel fluorescent probes, based on the excited-state intramolecular proton transfer (ESIPT) phenomenon and flavonols, sensitive to the action of specific glycosidases. 4′-Substituted flavonols were synthesized, using various approaches, and glycosylated withd-glucose,N-acetyl-d-glucosamine andd-glucuronic acid. Evaluation of the β-glycosidase activities was performed in neutral and acidic pH. In all the cases examined, an acidic environment accelerated enzymatic hydrolysis. It was demonstrated that the 4′-chloroflavonyl glycosides of all sugars tested, both in neutral and acidic pH, are the ones most sensitive to the presence of hydrolase. In turn, 4′-dimethylaminoflavonyl glucoside is not sensitive to glucosidase action at all. Generally, the rate of enzymatic hydrolysis increases as the electron-withdrawing nature of the 4′-substituent increases. An exception is the trifluoromethyl group which, in spite of having the most favourable Hammett constant, does not contribute enough to increase the rate of hydrolysis of its glucoside. The presented experimental results are supported by the electrostatic potential (ESP) analysis and related to the mechanisms of glycoside bond enzymatic hydrolysis.
Flavonol dyes with different substituents in photopolymerization
You, Jian,Fu, Hongyuan,Zhao, Di,Hu, Tianyu,Nie, Jun,Wang, Tao
, (2019/09/30)
To further expand the applications of flavonol dyes (3HFs) in photopolymerization, six flavonol dyes with different substituents were prepared by using the Algar–Flynn–Oyamada method. The steady-state photolysis and fluorescence quenching of 3HFs under the 385 nm LED light source showed that the proton transfer reaction preceded the charge transfer reaction between 3HFs and triethanolamine (TEOA) or iodonium salts (ONI), and groups with different electron properties could affect the photochemistry of 3HFs. The influence of substituents on the free radical polymerization efficiencies of 3HFs/TEOA and 3HFs/ONI was evaluated. Results showed that charge transfer occurred in the oxidation or reduction processes between 3HFs and TEOA or ONI. The possible mechanism was speculated, and the thermal feasibility of charge transfer between 3HFs and TEOA or ONI was calculated on the basis of the free energy changes of photoinduced electron transfer.
