- Reaction-based fluorescent silk probes with high sensitivity and selectivity to Hg2+and Ag+ions
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The detection and removal of heavy metals in the environment is urgent and meaningful. In this work, two types of fluorescent functionalized silksOSPandASPhave been prepared using worm silk as the substrate. These fluorescent silk probes exhibit an obvious fluorescence quenching effect in the presence of Hg2+or Ag+, enabling silk to specifically detect Hg2+or Ag+. An obvious color response occurs under visible light, from yellow to brown or gray, thereby realizing dual-channel identification of fluorescence and colorimetry. In addition, its sensing mechanism has been studied, and it is found that the probe reacts with metal ions as a reactive response. Compared with the fluorescent probes bearing one C-C/C-C bond, the probes with two terminal C-C/C-C bonds are more sensitive. And the excellent recognition ability can make the limit of detection as low as 0.25 μM. This indicates that silk fluorescent probes can be used to detect Hg2+and/or Ag+
- Cheng, Xinjian,Duan, Lian,Liu, Kaiqi,Xiao, Li
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p. 4877 - 4887
(2021/04/21)
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- Synthesis of a Photo-Caged DOPA Derivative by Selective Alkylation of 3,4-Dihydroxybenzaldehyde
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Natural and synthetic polymers containing the catechol moiety of noncoded amino acid 3,4-dihydroxyphenylalanine (DOPA) are capable of metal-coordination and adhesion under wet conditions. Masking the catechol subunit with a photo-cleavable group would provide an opportunity to design tunable adhesion properties that are especially important for biomaterial and biomedicine applications. Herein, we report the regioselective synthesis of a photo-caged DOPA bearing an ortho-nitrobenzyl (oNB) group that is capable of undergoing cleavage upon irradiation with UV light. We developed a selective synthetic route towards a 3-O-oNB alkylated DOPA regioisomer that can be readily incorporated into proteins by using a previously developed bio-expression platform. The synthesis is based on a regioselectivity switch in 3,4-dihydrozybenzaldehyde alkylation upon application of different equivalents of deprotonating base. The enantiomerically pure 3-O-oNB-DOPA was prepared on a gram scale and proved to be generally compatible with the solid-phase peptide synthesis conditions. We also demonstrate the general applicability of the developed synthetic strategy by providing the synthesis of 3-O-methyl-DOPA.
- Schneider, Tobias,Kubyshkin, Vladimir,Budisa, Nediljko
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p. 2053 - 2063
(2018/05/31)
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- Facile synthesis of vanillin-based novel bischalcones identifies one that induces apoptosis and displays synergy with Artemisinin in killing chloroquine resistant Plasmodium falciparum
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The inherent affinity of natural compounds for biological receptors has been comprehensively exploited with great success for the development of many drugs, including antimalarials. Here the natural flavoring compound vanillin has been used as an economical precursor for the synthesis of a series of novel bischalcones whose in vitro antiplasmodial activities have been evaluated against erythrocytic stages of Plasmodium falciparum. Bischalcones 9, 11 and 13 showed promising antiplasmodial activity {Chloroquine (CQ) sensitive Pf3D7 IC50 (μM): 2.0, 1.5 and 2.5 respectively}but only 13 displayed potent activities also against CQ resistant PfDd2 and PfIndo strains exhibiting resistance indices of 1.4 and 1.5 respectively. IC90 (8 μM) of 13 showed killing activity against ring, trophozoite and schizont stages. Further, 13 initiated the cascade of reactions that culminates in programmed cell death of parasites including translocation of phosphatidylserine from inner to outer membrane leaflet, loss of mitochondrial membrane potential, activation of caspase like enzyme, DNA fragmentation and chromatin condensation. The combinations of 13 + Artemisinin (ART) exhibited strong synergy (ΣFIC50:0.46 to 0.58) while 13 + CQ exhibited mild synergy (ΣFIC50: 0.7 to 0.98) to mild antagonism (ΣFIC50: 1.08 to 1.23) against PfIndo. In contrast, both combinations showed marked antagonism against Pf3D7(ΣFIC50: 1.33 to 3.34). These features of apoptosis and strong synergy with Artemisinin suggest that bischalcones possess promising antimalarial drug-like properties and may also act as a good partner drugs for artemisinin based combination therapies (ACTs) against Chloroquine resistant P. falciparum.
- Sharma, Upendra K.,Mohanakrishnan, Dinesh,Sharma, Nandini,Equbal, Danish,Sahal, Dinkar,Sinha, Arun K.
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p. 623 - 638
(2018/06/26)
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- Design, economical synthesis and antiplasmodial evaluation of vanillin derived allylated chalcones and their marked synergism with artemisinin against chloroquine resistant strains of Plasmodium falciparum
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The in vitro blood stage antiplasmodial activity of a series of allylated chalcones based on the licochalcone A as lead molecule was investigated against chloroquine (CQ) sensitive Pf3D7 and CQ resistant PfINDO strains of Plasmodium falciparum using SYBR Green I assay. Of the forty two chalcones tested, eight showed IC50 ≥ 5 μM. Structure-activity relationship (SAR) studies revealed 9 {1-(4-Chlorophenyl)-3-[3-methoxy-4-(prop-2-en-1-yloxy)phenyl] -prop-2-en-1-one} as the most potent (IC∑: 2.5 μM) against Pf3D7 with resistance indices of 1.2 and 6.6 against PfDd2 and PfINDO strains, respectively. Later on, the synergistic effects 9 with standard antimalarials {artemisinin (ART) and chloroquine (CQ)} were studied in order to provide the basis for the selection of the best partner drug. In vitro combinations of 9 with ART showed strong synergy against PfINDO (ΣFIC∑: 0.31-0.72) but additive to slight antagonistic effects (ΣFIC∑: 1.97-2.64) against Pf3D7. ΣFIC∑ 0.31 of ART+9 combination corresponded to a 320 fold and 3 fold reduction in IC∑ of 9 and ART, respectively. Similar combinations of 9 with CQ showed synergy to additivity to mild antagonism against the two strains {ΣFIC∑: 0.668-2.269 (PfINDO); 1.45-2.83 (Pf3D7)}. Drug exposure followed by drug withdrawal indicated that 9 taken alone at IC∑ killed rings, trophozoites and schizonts of P. falciparum. The combination of ART and 9 (1X ΣFIC∑) selectively inhibited the growth of rings while the 2X ΣFIC∑ combination of the same caused killing of rings without affecting trophozoites and schizonts. In contrast, the 1X combination of CQ and 9 (ΣFIC ∑: 0.5) killed rings and trophozoites. DNA fragmentation and loss of mitochondrial membrane potential (ΔΨm) in the 9 treated P. falciparum culture indicated apoptotic death in malaria parasites. Prediction of ADME properties revealed that most of the molecules did not violate Lipinski's parameters and have low TPSA value suggesting good absorption. The results suggest the promising drug-like properties of 9 against CQ resistant Pf and propensity for synergy with classical antimalarial drugs together with easy and economical synthesis.
- Sharma, Nandini,Mohanakrishnan, Dinesh,Sharma, Upendra Kumar,Kumar, Rajesh,Richa,Sinha, Arun Kumar,Sahal, Dinkar
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p. 350 - 368
(2014/05/06)
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- Butein disrupts hsp90's molecular chaperoning function and exhibits anti-proliferative effects against drug-resistant cancer cells
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Hsp90 shows great promise as a therapeutic target due to its potential to disable multiple signaling pathways simultaneously. In this study, we discovered that a natural product, butein moderately inhibited the growth of drug-resistant cancer cells (A2780cis and H1975), and brought about the degradation of oncogenic Hsp90 client proteins. The study demonstrated that butein would be a therapeutic lead to circumvent drug-resistance in cancer chemotherapy. The structure-based screening, synthesis, and biological evaluation of butein are described herein.
- Seo, Young Ho
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p. 3345 - 3349
(2014/01/06)
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- Synthesis and structure-activity relationships of serotonin derivatives effect on α-glucosidase inhibition
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The α-glucosidase inhibitory activities of serotonin derivatives were evaluated. Two serotonin derivatives, N-p-coumaroyl serotonin (2) and N-caffeoyl serotonin (4) exhibited most potent inhibition on α-glucosidase, whereas, cinnamic acid derivatives were
- Takahashi, Toshiyuki,Miyazawa, Mitsuo
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p. 1762 - 1770
(2012/11/14)
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- Synthesis of benzodioxepanes
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Four benzodioxepanes 1a-1d were prepared from reaction of 4-methoxy-3-hydroxybenzaldehyde 4 via a series of reasonable transformations, including the regioselective PhBCl2-mediated double allylation of 4, one-pot combination of ring-closing met
- Chang, Meng-Yang,Wu, Ming-Hao,Lee, Tein-Wei
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experimental part
p. 6224 - 6230
(2012/08/28)
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- Synthesis and structure-activity relationships of phenylpropanoid amides of serotonin on tyrosinase inhibition
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In this manuscript, we synthesized a series of phenylpropanoid amide of serotonin 1-9, analyzed their structural importance for two biologic activities (antioxidant activity and tyrosinase inhibitory activity). While the serotonin moiety and the amide linkage of serotonin derivatives affect antioxidant activity strongly, the serotonin moiety, the amide linkage and the cinnamic acid moiety affect tyrosinase inhibitory activity. Among tested compounds, compound 4 which contains cathechol moiety exhibited the most antioxidant activity (EC50 = 19.4 ± 2.0 μM), and compound 6 exhibited significant tyrosinase inhibitory activity (IC50 = 5.4 ± 3.6 μM). Our data suggests that a useful clue for the design and development of new tyrosinase inhibitors.
- Takahashi, Toshiyuki,Miyazawa, Mitsuo
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supporting information; experimental part
p. 1983 - 1986
(2011/04/24)
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- Serotonin derivatives as inhibitors of β-secretase (BACE 1)
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All serotonin derivatives described here (1-9) inhibited BACE 1 in a dose dependent manner. The 50% Inhibition Concentration (IC50) of N-cinnamoyl serotonin (1) was 86.7 ± 4.0 μM. The peptide conjugation of serotonin derivatives influenced the BACE 1 inhibitory activity. Among serotonin derivatives (1-8), introduction of substituents, such as hydroxyl and methoxy groups at the 4′-position decreased the inhibitory activity (N-p-coumaroyl serotonin (2), N-p-methoxy cinnamoyl serotonin (3)). With a hydroxylgroup at the 4′-position, and the meta-hydroxy function being substituted by a hydroxyl group or methoxy group (Ncaffeoyl serotonin (4), N-feruloyl serotonin (5)), inhibitory activity was weakened, (IC50 > 400 μM). BACE 1 inhibitory activity was effected by the substituents of the cinnamic acid moiety. This is the first report on Structure-Activity- Relationships (SAR) for the BACE 1-inhibiting activity of serotonin derivatives. These serotonin derivatives, which have anti-oxidative effects as well are expected to be useful in the study of the mechanisms of Alzheimer's disease.
- Takahashi,Miyazawa, Mitsuo
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experimental part
p. 301 - 305
(2012/01/02)
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- Studies on synthesis and structure-activity relationship (SAR) of derivatives of a new natural product from marine fungi as inhibitors of influenza virus neuraminidase
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Based on the natural isoprenyl phenyl ether from a mangrove-derived fungus, 32 analogues were synthesized and evaluated for inhibitory activity against influenza H1N1 neuraminidase. Compound 15 (3-(allyloxy)-4-hydroxybenzaldehyde) exhibited the most potent inhibitory activity, with IC50 values of 26.96 μM for A/GuangdongSB/01/2009 (H1N1), 27.73 μM for A/Guangdong/03/2009 (H1N1), and 25.13 μM for A/Guangdong/05/2009 (H1N1), respectively, which is stronger than the benzoic acid derivatives (~mM level). These are a new kind of non-nitrogenous aromatic ether Neuraminidase (NA) inhibitors. Their structures are simple and the synthesis routes are not complex. The structure-activity relationship (SAR) analysis revealed that the aryl aldehyde and unsubstituted hydroxyl were important to NA inhibitory activities. Molecular docking studies were carried out to explain the SAR of the compounds, and provided valuable information for further structure modification.
- Li, Jing,Zhang, Dingmei,Zhu, Xun,He, Zhenjian,Liu, Shu,Li, Mengfeng,Pang, Jiyan,Lin, Yongcheng
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experimental part
p. 1887 - 1901
(2011/12/04)
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- Towards the development of a covalently tethered MALDI system - A study of allyl-modified MALDI matrixes
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An emerging application of matrix-assisted laser desorption ionization (MALDI) mass spectrometry is the analysis of low molecular weight (LMW) compounds, often via coupled, liquid chromatography - MALDI-MS methods. However, in many cases, the low molecular weight region of MALDI mass spectra is obscured by the presence of signals originating from the matrix, suggesting that the development of tethered MALDI matrixes may be required to optimize MS performance for such compounds. To gain insight into potential sites for covalent attachment of MALDI matrixes, we have systematically investigated the role played by a variety of functional group motifs in determining matrix efficiency for three common MALDI matrixes, as judged both by total signal intensity and background noise from matrix decomposition for a set of LMW compounds. A series of allyl derivatives of standard matrixes was prepared, and the efficiency of these materials in the MALDI experiment was measured. All modifications of established matrixes, e.g., 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), and caffeic acid (CA), or close analogues led to decreased absolute signal intensity and signal-to-background levels. Improved performance was generally observed with (i) the presence of a phenolic group (carboxylic acids were less effective) (ii) crystalline derivatives, and (iii) compounds that had high extinction coefficients at wavelengths near to that of the exciting laser (337 nm). The most interesting derivatives were the O-allyl ether (15) and N-allyl amide (16) of caffeic acid. These compounds did not facilitate signals from all four analytes tested. However, the observed spectra contained fewer signals from the matrix than from the parent compound CA. These compounds demonstrate that functionalization of MALDI matrixes, ultimately leading to tethered matrixes, is possible without jeopardizing signal intensity.
- Martic, Sanela,Brennan, John D.,Brook, Michael A.,Ackloo, Suzanne,Nagy, Noemi
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-
- HYDRAZIDE DERIVATIVES
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A compound represented by the following general formula (1) or a salt thereof or a hydrate of the foregoing is safe while exhibiting suitable physicochemical stability, and is useful as therapeutic or prophylactic agents for diseases associated with thrombus formation. wherein R1a, R1b, R1c and R1d each independently represent hydrogen, etc., R2 represents optionally substituted phenyl, etc., R3 represents optionally substituted C6-10 aryl, etc., Z1, Z2 and Z3 each independently represent hydrogen, etc., Z4 represents hydrogen, etc. and X represents a single bond or -CO-, etc.
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-
Page/Page column 62-63
(2010/11/28)
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- Investigation of selective mono-deallylation of O,O′-diallylcatechols and 3-methylene-1,5-benzodioxepanes
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Selective mono-deallylation of O,O′-diallylcatechols using 10% Pd/C was investigated to give the corresponding allylphenols. A similar reaction of 3-methylene-1,5-benzodioxepanes afforded O-methacryl catecohols. When substrates bearing various substituents on the benzene ring were subjected to the reaction, regioselective cleavage of an ether bond occurred at the side of para position to an electron-withdrawing group on the aromatic ring. On the other hand, an electron-donating group did not cause any selectivity.
- Hayashida, Maiko,Ishizaki, Miyuki,Hara, Hiroshi
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p. 1299 - 1303
(2008/09/20)
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- Development of a functionalized xenon biosensor
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NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging
- Spence, Megan M.,Ruiz, E. Janette,Rubin, Seth M.,Lowery, Thomas J.,Winssinger, Nicolas,Schultz, Peter G.,Wemmer, David E.,Pines, Alexander
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p. 15287 - 15294
(2007/10/03)
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- Synthesis of 2H-1,5-benzodioxepin and 2,5-dihydro-1,6-benzodioxocin derivatives via ring-closing metathesis reaction
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The synthesis of various 2H-1,5-benzodioxepin and 2,5-dihydro-1,6- benzodioxocin derivatives is described. The key step involves the construction of seven- and eight-membered rings via ring-closing metathesis reaction.
- Mamouni,Soukri,Lazar,Akssira,Guillaumet
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p. 2631 - 2633
(2007/10/03)
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- Bryophyte constituents; 7: New synthesis of (+)-rosmarinic acid and related compounds
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Efficient and expeditious syntheses are described for rosmarinic acid (1) and its derivatives 2-4, making extensive use of allyl protective groups for both carboxylic acids and phenolic building blocks. (+)(R)-Rosmarinic acid was obtained by a chemoenzymatic resolution of its phenyl lactic acid precursors.
- Eicher, Theophil,Ott, Markus,Speicher, Andreas
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p. 755 - 762
(2007/10/03)
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- Regioselective Mono-O-alkylation of some Pyrocatechoxide Dianions
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In dimethyl sulphoxide the dianions derived from 2,3- or 3,4-dihydroxybenzaldehydes and 4-methylesculetin afford products corresponding to alkylation at the less acidic site while the monoanions give the isomeric phenols.
- Kessar, Satinder V.,Gupta, Yash P.,Mohammad, Taj,Goyal, Manju,Sawal, Kewal K.
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p. 400 - 401
(2007/10/02)
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