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Concept: Aurones

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The aim of the present work was to compare the antioxidative effect of the ferrocenyl-appended aurone with that of ferrocenyl-appended flavone; therefore, nine aurones together with the flavone-type analogues were synthesized by using chalcone as the reactant. The radical-scavenging property was evaluated by reacting with the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+·)), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical, respectively. The cytotoxicity was estimated by inhibiting 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced oxidation of DNA. It was found that the introduction of the ferrocenyl group remarkably increased the radical-scavenging activities of aurone and flavone. Especially, the ferrocenyl group in flavones can quench radicals even in the absence of the phenolic hydroxyl group, while ferrocenyl-appended aurones can efficiently protect DNA against AAPH-induced oxidation. Therefore, the antioxidative effect was generated by the ferrocenyl group and enhanced by the electron-donating group attaching to the para-position of the ferrocenyl group. Introducing the ferrocenyl group into natural compounds may be a useful strategy for increasing the antioxidative effectiveness.

Concepts: Alcohol, Functional group, Effect, Effectiveness, Vitamin C, Substituent, Chalcone, Aurones

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Polyphenol oxidases are involved in aurone biosynthesis but the gene responsible for 4-deoxyaurone formation in Asteraceae was so far unknown. Three novel full-length cDNA sequences from Coreopsis grandiflora were isolated with sizes of 1.80 kb (cgAUS1) and 1.85 kb (cgAUS2a, 2b), encoding for proteins of 68 to 69 kDa, respectively. cgAUS1 is preferably expressed in young petals indicating a specific role in pigment formation. The 58.9 kDa AUS1 holoproenzyme, was recombinantly expressed in E. coli and purified to homogeneity. The enzyme shows only diphenolase activity, catalyzing the conversion of chalcones to aurones and was characterized by SDS-PAGE and shot-gun type nanoUHPLC-ESI-MS/MS.

Concepts: DNA, Protein, Gene, Gene expression, Transcription, Molecular biology, Escherichia coli, Aurones

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Rhus parviflora (Anacardiaceae) is an indigenous medicinal shrub found in South Asia with flavonoid rich edible fruit. This study examined flavonoid derivatives of R. parviflora fruit with CDK5/p25 inhibition activity. Evaluation by in vitro assay and docking simulations for CDK5/p25 revealed that the aurones, sulfuretin (1) and aureusidin (2), the aurone glycoside, aureusidin-6-O-β-d-glucopyranoside (3) and hovetrichoside C (4), the flavonoid glycoside, quercetin-3-O-β-d-galactopyranoside (5), and the biflavonoid, cupressuflavone (6), had the potential to inhibit CDK5/p25, which could be useful in the treatment of neurodegenerative disorders such as Alzheimer’s disease. Compound2 showed the significant in vitro inhibition capacity (IC50 value of 4.81μM) as well as binding affinity with docking energy of -8.73 (kcal/mol) for active sites CYS83 and GLN130 of CDK5/p25 enzyme in comparison to reference compound R-roscovitine.

Concepts: Neurology, Neurodegenerative disorders, Enzyme inhibitor, Inhibitor, Xanthine oxidase inhibitor, Sumac, Aurones, Aureusidin

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Three aurone derivatives, Z-2-[(4-N,N-dimethylaminophenyl)methylene] benzofuran-3-one (1), Z-2-[(N-ethylcarbazol-3-yl)methylene]benzofuran-3-one (2) and Z-2-[(pyren-1-yl)methylene]benzofuran-3-one (3) have been synthesized by the cyclization of 2'-hydroxychalcones. Their crystal structure, single- and two-photon related absorption and fluorescence properties have been examined. Pumped by 860nm laser pulses in femtosecond regime, the compounds exhibit strong yellow-green two-photon excited fluorescence at 539nm (1), 505nm (2) and 524nm (3) in THF with two-photon absorption (TPA) cross-section being 1536GM (1), 608GM (2) and 236GM (3).

Concepts: Crystal, Photon, Chemical synthesis, Synthesis, Aurone, Aurones