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Coumarins are considered to be privileged structures due to their broad range of biological properties, including anticoagulant, anti-neurodegenerative, antioxidant, anticancer and antimicrobial activities. These interesting properties of coumarins can be ascribed to the chemical attributes of the 2H-chromen-2-one core; its aromatic ring can establish a series of hydrophobic, π-π, CH-π and cation-π interactions, and the two oxygen atoms in the lactone ring may hydrogen-bond to a series of amino acid residues in different classes of enzymes and receptors. Additionally, the double bond in the lactone helps to make the entire system planar, allows charge delocalization between the carbonyl group of the lactone and the aromatic ring and confers the characteristic fluorescence of this class of compounds, which can be explained by their preventing the trans-cis transformation of the double bond under ultraviolet (UV) irradiation. It is the possibility of radical delocalization in the 2H-chromen-2-one nucleus that makes most of the coumarins good antioxidants by acting as free radical scavengers, although some coumarins (mainly hydroxycoumarins) may also prevent the formation of free radicals by chelating metal ions. In this review, we provide a systematic analysis of the most important aspects surrounding the development of coumarins as antioxidants. Our analysis includes the synthesis of some complex antioxidant coumarins, strategies for structural modification to improve their antioxidant activities, qualitative/ quantitative structure-antioxidant relationships studies and the main in vitro assays used to evaluate their antioxidant properties.
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http://dx.doi.org/10.2174/1568026614666141203144551 | DOI Listing |
Mol Omics
December 2024
Department of Chemistry and Biochemistry, University of Texas at Arlington, Box 19065, 700 Planetarium Place, Room 130, Arlington, TX 76019, USA.
Designing reagents for protein labeling is crucial for investigating cellular events and developing new therapeutics. Historically, much effort has been focused on labeling lysine and arginine residues due to their abundance on the protein periphery. The chemo-selectivity of these reagents is a challenging yet crucial parameter for deciphering properties specifically associated with the targeted amino acid.
View Article and Find Full Text PDFNanotechnology
December 2024
Chemistry, American University, 4400 Massachusetts Ave NW, Washington, Washington, District of Columbia, 20016-8002, UNITED STATES.
A phenol contains a six-membered, conjugated, aromatic ring that is bound to a hydroxyl group. These molecules are important in biomedical studies, aromatic food preparation, and petroleum engineering. Traditionally, phenols have been measured with several analytical techniques such as UV-VIS spectroscopy, fluorescence, liquid chromatography, and mass spectrometry.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
University of Copenhagen, Department of Chemistry, Universitetsparken 5, DK-2100, Copenhagen, DENMARK.
The introduction of 4,5-dihydroazuleno[2,1,8-ija]azulene as a central core between two 1,4-dithiafulvene (DTF) units provides a novel class of extended tetrathiafulvalene (TTF) electron donors. Herein we present the synthesis of such compounds with the azulenoazulene further expanded by annulation to benzene, naphthalene, or thiophene rings. Moreover, unsymmetrical donor-acceptor chromophores with one DTF and one carbonyl at the central core are presented.
View Article and Find Full Text PDFChem Biodivers
December 2024
Jinan University, college of Pharmacy, 601, the west of Huangpu street, Not Available, 510632, Guangzhou, CHINA.
An unusual C15nor-halimane-type diterpenoid, norcrohalane A (1), a new nor-lasserane-type sesquiterpenoid, norcrolasane A (2), along with four known compounds (3-6) were isolated from the roots of Croton crassifolius. Compound 1 represents the first example of a C15nor-halimane-type diterpenoid, which features a rare 6/6/6 tricyclic ring system, and the A ring is aromatic. Compound 2 is a rare nor-lasserane-type sesquiterpenoid.
View Article and Find Full Text PDFChemistry
December 2024
Okayama University: Okayama Daigaku, Research Institute for Interdisciplinary Science, JAPAN.
Grafting carbon-based nanomaterials (CNMs) with polyglycerol (PG) improves their application potentials in biomedicine and electronics. Although "grafting from" method offers advantages over "grafting to" one in terms of operability and versatility, little is known about the reaction process of glycidol with the surface groups onto CNMs. By using graphene oxide (GO) as a multi-functional model material, we examined the reactivity of the surface groups on GO toward glycidol molecules via a set of model reactions.
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