Photogeneration of Superoxide Anion upon Illumination of Purines and Pyrimidines in the Presence of Riboflavin: Structure-activity Relationships

1980 ◽  
Vol 43 (1) ◽  
pp. 19-20 ◽  
Author(s):  
MALGORZATA KORYCKA-DAHL ◽  
THOMAS RICHARDSON
Keyword(s):  
Superoxide Dismutase ◽  
Superoxide Anion ◽  
Orotic Acid ◽  
Imidazole Ring ◽  
Fluorescent Light ◽  
Carboxyl Group ◽  
Amino Group ◽  
Structure Activity ◽  
Related Compounds ◽  
Purines And Pyrimidines

Photogenerated superoxide anion might be involved in the oxidative deterioration of foods. For this reason, purines, pyrimidines and related compounds were illuminated with fluorescent light in the presence of riboflavin to examine their capacity to photogenerate superoxide anion (measured from suppression of its reduction of nitro blue tetrazolium by superoxide dismutase). Superoxide anion was photogenerated in the presence of guanine, xanthine, 6-thioguanine, thymine, uracil, 6-methyl uracil, orotic acid and 5- as well as 6-amino uracil but not in the presence of 24 other related compounds examined. Replacing the oxygen at the 6-position of guanine with sulfur or attachment of an amino group to the 5- or 6-carbon of uracil greatly increased superoxide anion generation as compared to guanine and uracil, respectively. The attachment of a carboxyl group at the 6-position of uracil augmented superoxide anion photogeneration to a much smaller extent and thymine and 6-methyl uracil did not yield any more superoxide anion than did uracil. In general, only those compounds which had an oxo group at the 6-position of purines or the 4-position of pyrimidines, and either an oxo or an amino group in the 2-position of either ring served as substrates for photogeneration of superoxide anion. Additionally, presence of purines and pyrimidines in an enol and/or amino form and an unsubstituted imidazole ring for purines were required for photogeneration of superoxide anion.

scholarly journals New Histamine-Related Five-Membered N-Heterocycle Derivatives as Carbonic Anhydrase I Activators

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 545
Author(s):  
Niccolò Chiaramonte ◽  
Alessio Gabellini ◽  
Andrea Angeli ◽  
Gianluca Bartolucci ◽  
Laura Braconi ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Imidazole Ring ◽  
Aliphatic Chain ◽  
Amino Group ◽  
Carbonic Anhydrase I ◽  
Terminal Amino ◽  
Human Carbonic Anhydrase ◽  
New Compounds ◽  
Related Compounds ◽  
Micromolar Range

A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (KA values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII.

Effect of alkylated and intercalated DNA on the generation of superoxide anion by riboflavin

1988 ◽  
Vol 8 (5) ◽  
pp. 485-492 ◽  
Author(s):  
Imrana Naseem ◽  
Maqbool Ahmad ◽  
S. M. Hadi
Keyword(s):  
Ethidium Bromide ◽  
Superoxide Anion ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Fluorescent Light ◽  
Oxygen Species ◽  
Base Pairs ◽  
Double Stranded Dna ◽  
Purines And Pyrimidines ◽  
Stimulation Of

Superoxide anion (O2.-) was photogenerated upon illumination of riboflavin in fluorescent light. The rate of O2.- formation was stimulated by double stranded DNA but not by denatured DNA or RNA. Depurinated DNA, which was predominantly depleted in guanine residues, did not exhibit the stimulatory effect, indicating an interaction of riboflavin, or active oxygen species derived from it, with guanine bases. Also, the stimulation of O2.- photogeneration was not observed with ethidium bromide but was seen with proflavin-intercalated DNA. Since ethidium bromide intercalates preferentially between purines and pyrimidines, and proflavin prefers dA-dT rich sites, these results were interpreted to suggest that the interaction of riboflavin with DNA is mainly with GC or CG base pairs.

scholarly journals Zoosporicidal Activities of Anacardic Acids against Aphanomyces cochlioides

2002 ◽  
Vol 57 (9-10) ◽  
pp. 874-882 ◽  
Author(s):  
Parvin Begum ◽  
Yasuyuki Hashidoko ◽  
Md. Tofazzal Islam ◽  
Yuko Ogawa ◽  
Satoshi Tahara
Keyword(s):  
Active Agent ◽  
Anacardic Acid ◽  
Side Chain ◽  
Carboxyl Group ◽  
Methyl Derivative ◽  
Aphanomyces Cochlioides ◽  
Structure Activity ◽  
Related Compounds ◽  
Unripe Fruits ◽  
Motility Inhibition

The EtOAc soluble constituents of the unripe fruits of Ginkgo biloba showed motility inhibition followed by lysis of zoospores of the phytopathogenic Aphanomyces cochlioides. We purified 22:1-ω7-anacardic acid (1), 24:1-ω9-anacardic acid (2) and 22:0-anacardic acid (3), together with other related compounds, 21:1-ω7-cardol (4) and 21:1-ω7-cardanol (5) from the crude extracts of Ginkgo fruits. Amongst them, compound 1 was a major active agent in quality and quantity, and showed potent motility inhibition (98% in 30 min) followed by lysis (55% in 3 h) of the zoospores at 1 × 10−7 m. The 2-O-methyl derivative (1−c) of 1 displayed antibacterial activity against Bacillus subtilis, but practically inactive to Escherichia coli. A brief study on structure-activity relationships revealed that a carboxyl group on the aromatic ring and an unsaturated side chain in the anacardic acid derivative are important for strong motility inhibitory and lytic activities against the zoospore

scholarly journals Thiols as myeloperoxidase-oxidase substrates

1988 ◽  
Vol 253 (2) ◽  
pp. 441-449 ◽  
Author(s):  
B E Svensson
Keyword(s):  
Superoxide Dismutase ◽  
Carboxy Group ◽  
Free Amino ◽  
Ethyl Esters ◽  
Radical Scavenger ◽  
Amino Group ◽  
O2 Consumption ◽  
Structure Activity ◽  
Hydroxyl Radical Scavenger ◽  
High Concentrations

Nine low-Mr thiols were compared with regard to their ability to function as myeloperoxidase-oxidase substrates under conditions where no auto-oxidation of the thiols could be observed. The methyl and ethyl esters of cysteine were found to be about twice as active as cysteamine at pH 7.0, in terms of increased O2 consumption. Cysteine itself was poorly active, whereas glutathione, N-acetylcysteine and penicillamine were completely inactive as myeloperoxidase-oxidase substrates under these conditions. The structure-activity relationships indicated that both a free thiol and free amino group were required for peroxidase-oxidase activity, and also that a free carboxy group abolished activity. In analogy with cysteamine, the activities of both cysteine esters were inhibited by superoxide dismutase (less than 5 micrograms/ml) and by catalase and not by the hydroxyl-radical scavenger mannitol. In contrast with cysteamine, the activities of both cysteine esters were stimulated more than 2-fold by high concentrations (greater than 5 micrograms/ml) of superoxide dismutase. The activities of both cysteine esters exhibited broad pH optima at pH 7. A mechanism for the myeloperoxidase-oxidase oxidation of the cysteine esters is proposed, which is partly different from that previously proposed for cysteamine.

Experimental evidence for the amino-group non-planarity in nitroanilines: neutron diffraction study of 2-methyl-5-nitroaniline at 100 K

1999 ◽  
Vol 55 (2) ◽  
pp. 209-215 ◽  
Author(s):  
Javier Ellena ◽  
Andrés E. Goeta ◽  
Judith A. K. Howard ◽  
Chick C. Wilson ◽  
Juan C. Autino ◽  
...  
Keyword(s):  
Molecular Recognition ◽  
Neutron Diffraction ◽  
Experimental Evidence ◽  
Diffraction Study ◽  
Title Compound ◽  
Neutron Diffraction Study ◽  
Amino Group ◽  
X Ray ◽  
Related Compounds ◽  
Centrosymmetric Dimers

An appreciable degree of pyramidalization of the amine N atom is observed in the title compound. The existence of polar chains, induced by N—H...O synthons, is confirmed. C—H...O interactions, not noted in a previous X-ray study, were found to stabilize further the known head-to-tail assembling of the chains. The structure can be described as non-polar (101) layers, embodying chains interlinked by centrosymmetric dimers, connected by C(aryl)—H...π interactions. The latter are not present in m-nitroaniline, 2-methyl-4-nitroaniline and other related compounds with chains built from similar N—H...O synthons and assembled head-to-head. This finding implies that an obvious relationship between molecular recognition patterns and crystal structures should not be assumed.

ChemInform Abstract: Structure-Activity Relationships of trans-3,5-Disubstituted Pyrrolidinylthio-1β-methylcarbapenems. Part 1. J-111,347 and Related Compounds.

ChemInform ◽  
2010 ◽  
Vol 31 (20) ◽  
pp. no-no
Author(s):  
Hideaki Imamura ◽  
Norikazu Ohtake ◽  
Aya Shimizu ◽  
Hideki Jona ◽  
Hiroki Sato ◽  
...  
Keyword(s):  
Structure Activity Relationships ◽  
Structure Activity ◽  
Abstract Structure ◽  
Related Compounds

scholarly journals Modeling the Antileukemia Activity of Ellipticine-Related Compounds: QSAR and Molecular Docking Study

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 24 ◽  
Author(s):  
Edgar Márquez ◽  
José R. Mora ◽  
Virginia Flores-Morales ◽  
Daniel Insuasty ◽  
Luis Calle
Keyword(s):  
Molecular Structure ◽  
Binding Free Energy ◽  
Docking Study ◽  
Quantitative Structure Activity Relationship ◽  
Quantitative Structure ◽  
Molecular Docking Study ◽  
Modeling Simulation ◽  
Structure Activity ◽  
Related Compounds ◽  
Cancer Activity

The antileukemia cancer activity of organic compounds analogous to ellipticine representes a critical endpoint in the understanding of this dramatic disease. A molecular modeling simulation on a dataset of 23 compounds, all of which comply with Lipinski’s rules and have a structure analogous to ellipticine, was performed using the quantitative structure activity relationship (QSAR) technique, followed by a detailed docking study on three different proteins significantly involved in this disease (PDB IDs: SYK, PI3K and BTK). As a result, a model with only four descriptors (HOMO, softness, AC1RABAMBID, and TS1KFABMID) was found to be robust enough for prediction of the antileukemia activity of the compounds studied in this work, with an R2 of 0.899 and Q2 of 0.730. A favorable interaction between the compounds and their target proteins was found in all cases; in particular, compounds 9 and 22 showed high activity and binding free energy values of around −10 kcal/mol. Theses compounds were evaluated in detail based on their molecular structure, and some modifications are suggested herein to enhance their biological activity. In particular, compounds 22_1, 22_2, 9_1, and 9_2 are indicated as possible new, potent ellipticine derivatives to be synthesized and biologically tested.

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