- Chemical constituents of rhododendron lepidotum
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Two new coumarin glycosides, 7-O-β-D-glucopyranosyl-8- methoxybenzopyranone (1) and 7-hydroxy-8-O-β-glycosylbenzopyranone (2), are reported along with the isolation of 7,8-dihydroxy coumarin (daphnetin) from Rhododendron lepidotum (aerial part).
- Ahmad,Shakeel-U-Rehman,Chisti,Shaw,Taneja
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- C-alkylated coumarin and coumarin glycoside from Daphne oleoides
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New C-alkylated coumarin (1) and coumarin glucoside (2) have been isolated from the roots of Daphne oleoides. The structures of 1 and 2 were established through spectroscopic and chemical studies.
- Malik, Abdul,Riaz, Muhammad,Akbar, Erum,Rafique, Muhammad,Afza, Nighat
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Read Online
- Antagonistic activity of hydroxycoumarin-based antioxidants as possible singlet oxygen precursor photosensitizers
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Coumarins are phenolic-type compounds with efficient antioxidant activity due to their ability to scavenge reactive oxygen species. Nevertheless, their ability to behave as photosensitizers capable of generating reactive oxygen species, such as singlet oxygen, has been less studied. In this work, the photosensitizing ability of seven hydroxycoumarins was evaluated through the photooxidation of ergosterol by quantifying the conversion of ergosterol into ergosterol peroxide. In our experimental conditions, we found that almost every tested antioxidant coumarin promotes the peroxidation of ergosterol. The results suggest that the hydroxycoumarins exhibit potential photosensitizing activity by promoting singlet oxygen generation by a Type II photochemical mechanism. Density functional theory (DFT) calculations were also performed to obtain further insight into the chemical reactivity of tested compounds; the observed tendency in the group of antioxidant coumarins to promote the reaction was their hardness due to the principle of maximum hardness. To evaluate our conclusion, we performed the reaction using a highly polarizable coumarin as a photosensitizer, which resulted in an increased photosensitizing capacity supported with DFT calculations, which reinforces our analysis. Finally, we found that hydroxycoumarins can be potentially pro-oxidants since some of them can act as photosensitizers and generate singlet oxygen in the presence of UV–Vis light, a characteristic that must be considered when these compounds are used as antioxidants.
- Guerrero, Tomás,Vázquez-Ortega, Fernanda,Lagunes, Irene,Ortiz-Blanco, Erik,Sosa-Ortiz, Gabriela,Tovar-Miranda, Ricardo,Medina, Manuel E.,Trigos, ángel
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- Tumor diagnosis and treatment fluorescent probe for targeting tumor Wolburg effect
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The invention discloses a tumor diagnosis and treatment fluorescent probe for targeting tumor Warburg effect, and the structure of the fluorescent probe is shown as a formula (I). The fluorescent probe can be directly used in a cell line to analyze and detect the expression degree of tumor cell GLUT1 protein, so as to complete the screening of tumor cells. Meanwhile, tumor cell proliferation is inhibited by directly blocking the GLUT1 channel to inhibit intake of sugar nutritional ingredients by tumors. And an effective means and a useful tool are provided for early screening and diagnosis oftumors, development of new anti-tumor drugs and the like.
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Paragraph 0048-0053
(2020/11/02)
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- Strong antimicrobial activity of collinin and isocollinin against periodontal and superinfectant pathogens in vitro
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Periodontitis pathogenesis involves activation of host immune responses triggered by microbial dysbiosis. Therefore, controlling periodontal pathogens in-vivo is a main goal of periodontal therapy. New antimicrobials might help to control periodontal infection and improve treatment outcomes at “the dark times” of increasing antibiotic resistance. Here, we determined the biological activity of collinin and isocollinin against 8 bacterial strains. Antimicrobial activity of collinin and isocollinin, chlorhexidine digluconate (CHX) and sodium hypochlorite (NaClO) was evaluated against clinically relevant periodontal bacteria, like Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum, Prevotella intermedia, Dialister pneumosintes strains and superinfectants like Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. A broth microdilution test was carried out to determine the minimum inhibitory concentration of collinin and isocollinin against those strains, and bacterial viability was determined by resazurin assay at diverse concentration and exposure times. P. gingivalis was the most susceptible strain to collinin and isocollinin (MIC 2.1 μg/mL and 4.2 μg/mL respectively). Other periodontal pathogens showed MICs 17 μg/mL for collinin and MICs between 20 and 42 μg/mL for isocollinin, whereas CHX and NaClO showed MICs of 62 and 326 μg/mL, respectively. Collinin and isocollinin also exhibited antimicrobial activity against superinfectant bacteria (MIC 21 and 42 μg/mL, respectively). Overall, collinin and isocollinin showed a remarkable antibacterial activity against relevant periodontal and superinfective bacteria, especially against P. gingivalis (MIC 2.1 μg/mL and 4.2 μg/mL respectively) and the highly virulent P. aeruginosa (MIC 5.2 and 20.8 μg/mL, respectively).
- Bola?os, Gustavo,Contreras, Adolfo,Pardo-Casta?o, Camilo,Vásquez, Daniel
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- Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran-2-one Aromaticity-Mediated Regioselective Control and Biogenetic Implications
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The synthetic feasibility of the oxidative cleavage: epoxidation of 7-O-geranylscopoletin followed by electrocyclic ring-opening, proposed in the biogenesis of transtaganolides/basiliolides is studied. Unlike the proposed pericyclic reactions, this pathway has not yet been addressed. Three synthetic strategies have been tested consisting of: i) Baeyer–Villiger oxidation of p-quinoids, ii) hydrolysis of quinone monoketals, or iii) direct fragmentation by using oxygen donors. Oxidation of the benzene ring of hydroxylated coumarins has been achieved using peroxyacids, but cleavage took place between undesired positions. The aromaticity conservation of the pyran-2-one cycle during oxidation is the controlling factor of these observed regioselectivities. The use of a 4,5-dihydroxy-2-methoxycinnamate model, in which the pyran-2-one ring does not exert influence on oxidation, has allowed the design of a synthetic sequence toward an analogue of the natural pyran-2-one isolated from Thapsia transtagana, key in the biogenesis. Mechanistic proposals for the obtained results as well as their biogenetic implications are raised.
- álvarez, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
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supporting information
(2020/03/05)
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- Solubility of Collinin and Isocollinin in Pressurized Carbon Dioxide: Synthesis, Solubility Parameters, and Equilibrium Measurements
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Collinin is a derivative of coumarin that has shown remarkable potential against cancer, tuberculosis, periodontitis, and other prevalent diseases, and is usually extracted from plants of the Rutaceae family at a very low yield. In this work, collinin and a position-isomer herein called isocollinin were synthesized at different scales (from 1 to 50 g of precursor) by a route consisting of two parallel and two sequential chemical reactions. The isomers were characterized by 1H NMR, 13C NMR, nuclear Overhauser enhancement spectroscopy NMR, melting temperature, and melting enthalpy. For each isomer, the Hansen solubility parameters and the radius of its solubility sphere were experimentally determined by solubility tests in 15 common solvents and two solvent blends. The solubility of each isomer in pressurized CO2 was determined at 30 and 50 °C from 72.2 to 112.9 bar, by an in situ high-pressure spectrometry technique, which was validated with the anthracene-CO2 system. The solubility of both isomers in CO2 increased with pressure in the range of temperatures and pressures considered, but that of collinin exhibited an asymptotic behavior around 80.8 and 104.8 bar, at 30 and 50 °C, respectively.
- Pardo-Casta?o, Camilo,García, Andrés C.,Benavides, Paola,Bola?os, Gustavo
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p. 3799 - 3810
(2019/09/30)
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- Regioselective IBX-Mediated Synthesis of Coumarin Derivatives with Antioxidant and Anti-influenza Activities
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Different catechol and pyrogallol derivatives have been synthesized by oxidation of coumarins with 2-iodoxybenzoic acid (IBX) in DMSO at 25 °C. A high regioselectivity was observed in accordance with the stability order of the incipient carbocation or radical benzylic-like intermediate. The oxidation was also effective in water under heterogeneous conditions by using IBX supported on polystyrene. The new derivatives showed improved antioxidant effects in the DPPH test and inhibitory activity against the influenza A/PR8/H1N1 virus. These data represent a new entry for highly oxidized coumarins showing an antiviral activity possibly based on the control of the intracellular redox value.
- Bizzarri, Bruno M.,Botta, Lorenzo,Capecchi, Eliana,Celestino, Ignacio,Checconi, Paola,Palamara, Anna T.,Nencioni, Lucia,Saladino, Raffaele
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p. 3247 - 3254
(2018/01/02)
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- An Optimized Two-Photon Fluorescent Probe for Biological Sensing and Imaging of Catechol-O-Methyltransferase
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A practical two-photon fluorescent probe was developed for highly sensitive and selective sensing of the activities of catechol-O-methyltransferase (COMT) in complex biological samples. To this end, a series of 3-substituted 7,8-dihydroxycoumarins were designed and synthesized. Among them, 3-BTD displayed the best combination of selectivity, sensitivity, reactivity, and fluorescence response following COMT-catalyzed 8-O-methylation. The newly developed two-photon fluorescent probe 3-BTD can be used for determining the activities of COMT in complex biological samples and bio-imaging of endogenous COMT in living cells and tissue slices with good cell permeability, low cytotoxicity, and high imaging resolution. All these findings suggest that 3-BTD holds great promise for developing therapeutic molecules that target COMT, as well as for exploring COMT-associated biological processes and its biological functions in living systems. Furthermore, the strategy also sheds new light on the development of fluorescent probes for other conjugative enzymes.
- Wang, Ping,Xia, Yang-Liu,Zou, Li-Wei,Qian, Xing-Kai,Dou, Tong-Yi,Jin, Qiang,Li, Shi-Yang,Yu, Yang,Wang, Dan-Dan,Luo, Qun,Ge, Guang-Bo,Yang, Ling
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p. 10800 - 10807
(2017/08/18)
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- Ytterbium triflate promoted coupling of phenols and propiolic acids: Synthesis of coumarins
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Coumarins are a well-known class of natural occurring and semi-synthetic products with reported important and effective pharmacological activities. In this Letter an improved method for the chemical synthesis of such compounds is described. Coumarins have been obtained in good to excellent yields under microwave irradiation and solvent-free conditions in a short time from differently substituted phenols and propiolic acids used as starting materials in the presence of Yb(OTf)3 hydrate 10% mol as the catalyst.
- Fiorito, Serena,Epifano, Francesco,Taddeo, Vito A.,Genovese, Salvatore
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supporting information
p. 2939 - 2942
(2016/06/14)
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- Total synthesis of six 3,4-unsubstituted coumarins
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In this article we describe a new methodology for the total synthesis of 3,4-unsubstituted coumarins from commercially available starting materials. Six examples were prepared, including five naturally occurring coumarins-7-hydroxy- 6,8-dimethoxycoumarin (isofraxidin), 7-hydroxy-6-methoxycoumarin (scopoletin), 6,7,8-trimethoxycoumarin, 6,7-dimethoxycoumarin (scoparone), and 7,8-dihydroxycoumarin (daphnetin) and one synthetic coumarin, 7-hydroxy-6-ethoxycoumarin. Moreover, five important o-hydroxybenzaldehyde intermediates were also obtained, namely 2,4-dihydroxy-3,5- dimethoxybenzaldehyde, 2,4-dihydroxy-5-methoxybenzaldehyde, 5-ethoxy-2,4- dihydroxybenzaldehyde, 2-hydroxy-3,4,5-trimethoxybenzaldehyde, and 2-hydroxy-4,5-dimethoxybenzaldehyde. The method developed herein involves just three or four steps and allows for the rapid synthesis of these important molecules in excellent yields. This is the first synthesis of 6,7,8-trimethoxycoumarin and 7-hydroxy-6-ethoxycoumarin.
- Gao, Wenqing,Li, Qingyong,Chen, Jian,Wang, Zhichao,Hua, Changlong
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p. 15613 - 15623
(2014/01/17)
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- Synthesis and spectral characterization of a novel series of methylcinnamate derivatives of 15-crown-5
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(Chemical Equation Presented) A series of novel methylcinnamate derivatives of 15-crown-5 have been synthesized. The derivatives of methylcinnamate have been prepared by a synthesis from the corresponding chromenone-crown ether with MeONa/MeOH or KOH, CH3I, and DMSO as solvent. Novel compounds were characterized by elemental analysis, IR, 1H NMR, and MALDI-TOF.
- Guenduez, Cihan,Salan, Uemit,Bulut, Mustafa
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scheme or table
p. 567 - 570
(2009/09/06)
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- Synthesis of collinin, an antiviral coumarin
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The synthesis of collinin, an antivirus coumarin was presented. Collinin was synthesized in three steps and 24.6% overall yield from pyrogallol and propiolic acid. The coumarin nucleas 7,8-dihydroxycoumarin was made using a concentrated H2SO4 catalyzed Pechmann-type condensation between pyrogallol and propiolic acid under solvent free conditions at 120°C for 30 minutes. The method presented an alternative and valuable route to obtain collinin for biological test purposes.
- Curini, Massimo,Epifano, Francesco,Maltese, Federica,Marcotullio, Maria Carla,Gonzales, Sylvia Prieto,Rodriguez, Juan Carlos
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- Synthesis and antihepatotoxic activity of some heterocyclic compounds containing the 1,4-dioxane ring system
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Silymarin isolated from Silybum marianum is a mixture of three isomers, silybin (1), silydianin (2) and silychristin (3). Silybin is the most active antihepatotoxic agent, and contains a 1,4-dioxane ring in addition to a flavonoid moiety. Based on the skeleton of silybin, we prepared some flavones and coumarins containing the 1,4-dioxane ring system and evaluated them for antihepatotoxic activity against carbon tetrachloride induced hepatotoxicity in albino rats. The degree of protection was determined by measuring biochemical parameters such as serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvate transaminase (SGPT), alkaline phosphatase (ALKP), total protein (TP) and total albumin (TA). The compounds namely 3′,4′(1″,4″-dioxino) flavone (4f), and 3′,4′(2-hydroxy methyl, 1′,4″-dioxino) flavone (4g) were found to exhibit a significant activity comparable to standard drug silymarin (silybon-70). Other compounds also exhibited good activity. The structure activity relationship (SAR) was also studied, and where the flavonoid analogues containing a hydroxy methyl group at position-2″ in the dioxane ring exhibited superior antihepatotoxic activity in comparison to coumarin derivatives.
- Ahmed,Khan,Alam
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p. 173 - 176
(2007/10/03)
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- Coumarin glucosides from Cruciata taurica
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Two new coumarin glycosides (1 and 2) along with two known coumarin glucosides, daphnin (3) and daphnetin glucoside (4) were isolated from the aerial parts of Cruciata taurica. The structures of the new compounds were elucidated by spectral methods and ch
- De Rosa, Salvatore,Mitova, Maya,Handjieva, Nedjalka,Cals, Ihsan
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p. 447 - 450
(2007/10/03)
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- Antioxidant properties of anthocyanins and tannins: A mechanistic investigation with catechin and the 3′,4′,7-trihydroxyflavylium ion
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Plant polyphenols act as antioxidants mainly by trapping reactive oxygen species and by regenerating endogenous membrane-bound α-tocopherol (vitamin E). In both processes polyphenols are oxidized. Hence, knowledge of the oxidation mechanisms of polyphenols is important for an understanding of their antioxidant activity at the molecular level. This work focuses on anthocyanins (pigments) and flavanols (tannins), two important classes of polyphenols which are both relatively abundant in human diet. The oxidation of the 3′,4′,7-trihydroxyflavylium ion (1) and catechin (2), respectively taken as models for anthocyanins and tannins, has been investigated. From kinetic data and partial product analysis, the mechanisms for the reactions of 1 and 2 with sodium periodate and DPPH, a H atom-abstracting radical, are proposed. Both polyphenols are shown to form o-quinone intermediates upon H atom abstraction and subsequent radical disproportionation. In the case of 2, the quinone and a second molecule of antioxidant quickly couple to form dimers. By contrast, 1 is extensively degraded into coumarins by repeating sequences of oxidation-solvent addition, which consume several equivalents of oxidants. In aqueous solutions, 1 is typically a mixture of coloured and colourless forms. The latter (chalcones) are also shown to take part in the antioxidant activity.
- Dangles, Olivier,Fargeix, Guillaume,Dufour, Claire
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p. 1653 - 1663
(2007/10/03)
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- A new synthesis of 1,4/1,5- dioxanocoumarins
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7,8-Dihydroxycoumarins 2a-c on reaction with epichlorohydrin in the presence of acetone-potassium carbonate medium give 1,4- and 1,5- dioxanocoumarins 3a-b, 4a-c and 5a-c in a good yields.
- Gangadhar,Harish Kumar,David Krupadanam
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p. 470 - 472
(2007/10/03)
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- A new coumarin glucoside from Daphne arisanensis
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A new coumarin glucoside named daphneside was isolated along with two known coumarin glucosides, daphnin and daphnetin-(S)-glucoside, and two known phenylpropanoid glucosides, syringin and syringinoside, from a water-soluble fraction of Daphne arisanensis HAYATA (Thymelaeaceae) collected in Taiwan. The structure of daphneside was elucidated by spectroscopic and chemical methods.
- Niwa,Sugino,Takashima,Sakai,Wu,Wu,Kuoh
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p. 2422 - 2424
(2007/10/02)
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- Natural Product Chemistry. Part 121. Synthesis of Dicoumarinyl Ethers with the Structures Proposed for Fatagarine and Oreojasmine
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Synthesis of the 7,8'-dicoumarinyl ethers: 7-methoxy-7',8-oxydicoumarin and 6,7-dimethoxy-7',8-oxydicoumarin, established that the structures of fatagarine and oreojasmine for which these two structures have been proposed, have to be revised.Synthesis of 7-methoxy-5,7'-oxydicoumarin and 8-methoxy-7,7'-oxydicoumarin exclude the possibility of these dicoumarinyl ether structures for fatagarine. - Keywords: Dicoumarinyl ethers; 6,7-Dimethoxy-7',8-oxydicoumarin; Fatagarine; 7-Methoxy-5,7'-oxydicoumarin; 8-Methoxy-7,7'-oxydicoumarin; 7-Methoxy-7',8-oxydicoumarin; Oreojasmine; Ruta oreojasme
- Reisch, Johannes,Wickramasinghe, Anura,Kumar, Vijaya
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p. 1333 - 1339
(2007/10/02)
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- Studies on Rutaceae: Part II - Chemical Investigations of the Constituents of Atlantia Wightii, Limon creniaulata, Feronia limonia, Citrus limon and Synthesis of Luvangetin, Xanthyletin and Marmin
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Four different species of Rutaceae belonging to the genera Atalantia, Limonia, Feronia and Citrus have been subjected to thorough chemical investigation.Convenient and simple syntheses of luvangetin (II), a major constituent of Limonia crenulata, xanthyletin (I), obtained from Citrus limon and marmin (IX), a lactonic constituent of Feronia limonia, have been described.
- Banerji, J.,Ghoshal, N.,Sarkar, S.,Kumar, M.
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p. 496 - 498
(2007/10/02)
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- Complexes of Cu(II) with Some Biologically Active Dihydroxycoumarins
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Complexes of Cu(II) with hydroxycoumarins, viz. esculetin, daphnetin and their 4-methyl and 4-phenyl derivatives have been prepared.The general composition of the complexes is .The water molecules are replaced on reaction with pyridine or ammonia to give complexes of the type (where X = NH3 or C5H5N).IR studies show that more acidic of the two phenolic hydroxyl groups present at C-7 in the ligand is involved in complexation in the parent complexes.Thermal studies on the parent complexes indicate the formation of two intermediate compounds which correspond to the compositions and but only one intermediate, , is formed on heating the pyridine or ammonia adducts.
- Singh, H. B.,Negi, R. K.,Srivastava, Smita
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p. 1026 - 1028
(2007/10/02)
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- COUMARINS IN ARTEMISIA CARUIFOLIA
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Isolation of daphnetin 7-methyl ether, daphnetin dimethyl ether, daphnetin methylene ether, daphnetin 7-methyl-8(3,3-dimethylallyl) ether and 3,4-dimethoxy-2-hydroxycinnamic acid from Artemisia caruifolia is reperted. - Key Word Index: Artemisia caruifolia; Compositae; coumarins; daphnetin derivatives; 3,4-dimethoxy-2-hydroxycinnamic acid.
- Barua, Nabin C.,Sharma, Ram P.,Madhusudanan, K. P.,Thyagarajan, Gopalakrishna,Herz, Werner
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p. 2217 - 2218
(2007/10/02)
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- The Chemical Components of Artemisia apiacea HANCE. II. More Coumarins from the Flower Heads
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A new coumarin, 7-isopentenyloxy-8-methoxycoumarin, was isolated together with 7-hydroxy-8-methoxycoumarin and daphnetin from the flower heads of Artemisia apiacea HANCE. Keywords: Artemisia apiacea HANCE; Compositae; coumarins; daphnetin; 7-hydroxy-8-methoxycoumarin; 7-isopentenyloxy-8-methoxycoumarin
- Shimomura, Hiroko,Sashida, Yutaka,Ohshima, Yukio
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p. 347 - 348
(2007/10/02)
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