6889-78-7Relevant academic research and scientific papers
3-HYDROXY-4'-METHOXYFLAVONE FROM MILLATTIA ZECHIANA
Parvez, M.,Ogbeide, O. N.
, p. 2043 - 2044 (1990)
3-Hydroxy-4'-methoxyflavone was identified for the first time from flowers of Millettia zechiana and its structure established from its chemical characteristics and from its synthesis.In addition known glycosides of kaempferol, quercetin, malvidin, cyanid
Excited state and ground state proton transfer rates of 3-hydroxyflavone and its derivatives studied by shpol'skii spectroscopy: The influence of redistribution of electron density
Bader, Arjen N.,Pivovarenko, Vasyl G.,Demchenko, Alexander P.,Ariese, Freek,Gooijer, Cees
, p. 10589 - 10595 (2004)
We studied the mechanisms of excited-state intramolecular proton transfer (ESIPT) and ground-state back proton transfer (BPT) in 3-hydroxyflavone (3HF) at cryogenic temperatures. The focus was on substituents that change the distribution of electronic den
A Fluorogenic Molecule for Probing Islet Amyloid Using Flavonoid as a Scaffold Design
Chan, Ai-Ci,Chao, Yen-Cheng,Chen, Wei-Ling,Chen, Yun-Wen,Liu, Wei-Min,Ma, Shih-Ting,Tu, Ling-Hsien
, p. 1482 - 1492 (2020)
Aggregation of polypeptides and proteins is commonly associated with human and other vertebrate diseases. For example, amyloid plaques consisting of amyloid-β proteins are frequently identified in Alzheimer's disease and islet amyloid formed by islet amyloid polypeptide (IAPP, amylin) can be found in most patients with type 2 diabetes (T2D). Although many fluorescent dyes have been developed to stain amyloid fibrils, very few examples have been designed for IAPP. In this study, a series of environmentally sensitive fluorescent probes using flavonoid as a scaffold design are rationally designed and synthesized. One of these probes, namely 3-HF-ene-4′-OMe, can bind to IAPP fibrils but not nonfibrillar IAPP by exhibiting a much stronger fluorescent enhancement at 535 nm. In addition, this probe shows better detection sensitivity to IAPP fibrils compared with that of conventionally used thioflavin-T. We demonstrate that 3-HF-ene-4′-OMe can be used to monitor the kinetics of IAPP fibril formation in vitro even in the presence an amyloid inhibitor. To test the specificity of the probe, we attempt to incubate this probe with amyloid fibrils formed from other amyloidogenic proteins. Interestingly, this probe shows different responses when mixed with these fibrils, suggesting the mode of binding of this probe on these fibrils could be different. Moreover, we show that this probe is not toxic to pancreatic mouse β-cells. Further structural optimization based on the structure of 3-HF-ene-4′-OMe may yield a specific probe for imaging islet amyloid in the pancreas. That would improve our understanding of the relationship between islet amyloid and T2D.
Synchronous Fluorescence Determination of Al3+ Using 3-Hydroxy-2-(4-Methoxy Phenyl)-4H-Chromen-4-One as a Fluorescent Probe
Bhogal, Shikha,Sharma, Promila,Rani, Pooja,Kaur, Kuldeep,Malik, Ashok Kumar
, p. 359 - 367 (2021/12/06)
A simple synchronous fluorescent chemosensor 3-hydroxy-2-(4-methoxyphenyl)-4H-chromen-4-one (3-HC) has been synthesized for the selective analysis of Al3+. On the addition of Al3+, 3-HC displayed a redshift with a change in wavelength of emission maximum from 436 to 465?nm along with enhancement in fluorescence intensity, which formed the basis for its sensitive detection. Under optimized conditions, 3-HC was applied for the determination of Al3+ in the concentration range of 1 × 10–7-1 × 10–6?M. The limit of detection (LOD) and limit of quantification (LOQ) values were found out to be 1.69 × 10–8 and 5.07 × 10–8?M respectively. Further, the developed method was applied for the analysis of Al3+ in real water samples (tap water, bottled water, and tube well water) which showed good recovery values in the range of 95–99.7% with RSD less than 4%.
Exploring 3-Benzyloxyflavones as new lead cholinesterase inhibitors: synthesis, structure–activity relationship and molecular modelling simulations
Mughal, Ehsan Ullah,Sadiq, Amina,Ayub, Momna,Naeem, Nafeesa,Javid, Asif,Sumrra, Sajjad Hussain,Zafar, Muhammad Naveed,Khan, Bilal Ahmad,Malik, Fouzia Perveen,Ahmed, Ishtiaq
, p. 6154 - 6167 (2020/08/10)
In this protocol, a series of 3-benzyloxyflavone derivatives have been designed, synthesized, characterized and investigated in?vitro as cholinesterase inhibitors. The findings showed that all the synthesized target compounds (1–10) are potent dual inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes with varying IC50 values. In comparison, they are more active against AChE than BChE. Remarkably, amongst the series, the compound 2 was identified as the most active inhibitor of both AChE (IC50 = 0.05 ± 0.01 μM) and BChE (IC50 = 0.09 ± 0.02 μM) relative to the standard Donepezil (IC50 = 0.09 ± 0.01 for AChE and 0.13 ± 0.04 μM for BChE). Moreover, the derivatives 5 (IC50 = 0.07 ± 0.02 μM) and 10 (0.08 ± 0.02 μM) exhibited the highest selective inhibition against AChE as compared to the standard. Preliminary structure-activity relationship was established and thus found that cholinesterase inhibitory activities of these compounds are highly dependent on the nature and position of various substituents on Ring-B of the 3-Benzyloxyflavone scaffolds. In order to find out the nature of binding interactions of the compounds and active sites of the enzymes, molecular docking studies were carried out. (Figure presented.) HIGHLIGHTS 3-benzyloxyflavone analogues were designed, synthesized and characterized. The target molecules (1–10) were evaluated for their inhibitory potential against AChE and BChE inhibitory activities. Limited structure-activity relationship was developed based on the different substituent patterns on aryl part. Molecular docking studies were conducted to correlate the in?vitro results and to identify possible mode of interactions at the active pocket site of the enzyme. Communicated by Ramaswamy H. Sarma.
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.
Bismuth(III) Flavonolates: The Impact of Structural Diversity on Antibacterial Activity, Mammalian Cell Viability and Cellular Uptake
Burke, Kirralee J.,Stephens, Liam J.,Werrett, Melissa V.,Andrews, Philip C.
, p. 7657 - 7671 (2020/06/02)
A series of homoleptic and heteroleptic bismuth(III) flavonolate complexes derived from six flavonols of varying substitution have been synthesised and structurally characterised. The complexes were evaluated for antibacterial activity towards several problematic Gram-positive (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE)) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. The cell viability of COS-7 (monkey kidney) cells treated with the bismuth flavonolates was also studied to determine the effect of the complexes on mammalian cells. The heteroleptic complexes [BiPh(L)2] (in which L=flavonolate) showed good antibacterial activity towards all of the bacteria but reduced COS-7 cell viability in a concentration-dependent manner. The homoleptic complexes [Bi(L)3] exhibited activity towards the Gram-positive bacteria and showed low toxicity towards the mammalian cell line. Bismuth uptake studies in VRE and COS-7 cells treated with the bismuth flavonolate complexes indicated that Bi accumulation is influenced by both the substitution of the flavonolate ligands and the degree of substitution at the bismuth centre.
Synthesis of Flavonols via Pyrrolidine Catalysis: Origins of the Selectivity for Flavonol versus Aurone
Xiong, Wei,Wang, Xiaohong,Shen, Xianyan,Hu, Cuifang,Wang, Xin,Wang, Fei,Zhang, Guolin,Wang, Chun
supporting information, p. 13160 - 13176 (2020/11/23)
A novel synthetic method for flavonol from 2′-hydroxyl acetophenone and benzaldehyde promoted by pyrrolidine under an aerobic condition in water is established. This protocol was supported by efficient synthesis of 44 common examples and three natural products. The α, β-unsaturated iminium ion (enimine ion E) was proved to be the key intermediate in the reaction. H218O and 18O2 isotope tracking experiments demonstrated that both water and the aerobic atmosphere were necessary to ensure the transformation. The selectivity for flavonol or aurone was originated from solvent-triggered intermediates, which were determined by UV-visible spectra from isolated enimine. The phenol-iminium E-A is dominant in water and the ketoenamine intermediate E-B is prevalent in acetonitrile. In the presence of pyrrolidine and oxygen, E-A leads to flavonol through E-I, a zwitterionic-like phenoloxyl-iminium ion, following the key steps of cyclization and a [2 + 2] oxidation; E-B proceeds through path II, a radical process induced by photolysis of E-B with both pyrrolidine and oxygen, to afford aurone. Preliminary mechanistic studies are reported.
Faster and More Specific: Excited-State Intramolecular Proton Transfer-Based Dyes for High-Fidelity Dynamic Imaging of Lipid Droplets within Cells and Tissues
Jiang, Gangwei,Jin, Yi,Li, Man,Liu, Changlin,Liu, Chunrong,Ren, Zhuqing,Wang, Huiling,Xiong, Mengyao,Yuan, Hong,Zeng, Weili
, p. 10342 - 10349 (2020/09/18)
Lipid droplets (LDs), a type of dynamic organelle residing at the center of cellular lipid storage, have been identified to play important roles in multiple biological processes, metabolic disorders, and diseases. The highly dynamic characters of LDs were found to correspond to their physiological and pathological functions. Hence, the fluorescent probes which enable dynamic tracking of LDs should be very helpful for better understanding the mechanisms of LDs involved biological processes and diseases. Herein we present, to the best of our knowledge, the first class of excited-state intramolecular proton transfer (ESIPT) fluorescence dyes (Flp-(11-13, 19)) for dynamic imaging of LDs based on 3-hydroxyflavone (3HF) derivatives. Flp-(11-13, 19) display strong fluorescence from yellow to NIR in lipid but exhibit almost nonfluorescence in aqueous solution. Besides, they also show large Stokes shifts (>150 nm), narrow absorption and emission peaks, and good oil-water separation efficiency, which makes them specifically target and stain LDs with very low background noisy in both living cells and fixed cells. They stain intracellular LDs quite quickly (within 30 s) with very low dosage (as low as 500 nM). Benefitting from these advantages, Flp-(11-13, 19) are applied successfully in tracking the dynamic nature of LDs and accumulation of LDs in both aqueous solution and living cells, 3D imaging of LDs for visualization of their repartition within the cells, and visualizing LDs in tissues of diseases mice models including adipose, skeletal muscle, and fatty liver tissues, underscoring the potential utility of these dyes in both LDs biology research and medical diagnosis of LDs involved diseases.
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.
