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PubMed2006

A triethylenetetramine bearing anthracene and benzophenone as a fluorescent molecular logic gate with either-or switchable dual logic functions.

Fluorescence behaviors of a triethylenetetramine bearing anthracene (AN) and benzophenone (BP) fragments at the respective ends, L1, have been studied in water, where effects of pH (H+) and metal cations on the emission properties have been studied in detail. L1 behaves as a fluorescent molecular logic gate driven by H+ (Input1) and metal cations (Input2) as input chemicals. The most notable feature of L1 is that this molecule expresses the "either-or" switchable dual logic functions. Operation of L1 with Cu2+ as Input2 expresses the INHIBIT logic function, where a strong AN fluorescence appears only at pH 4 (with H+) without Cu2+ [Input1(1)-Input2(0)]. In contrast, operations of L1 with all other metal cations as Input2 express the TRANSFER logic function, where the presence of H+ allows strong AN fluorescence regardless of whether the metal cation exists or not [Input1(1)-Input2(0); Input1(1)-Input2(1)]. These emission switching behaviors of L1 are driven by the difference in the coordination stability between L1 and metal cations and the photoinduced intramolecular electron and energy transfer processes: (i) a pH-induced electron transfer from unprotonated nitrogen atoms of the polyamine chain to the photoexcited AN [ELT(N-->AN*)]; (ii) a pH- and metal coordination-induced electron transfer from the photoexcited AN to the ground-state BP [ELT(AN*-->BP)]; and (iii) a Cu2+ coordination-induced energy transfer from the photoexcited AN to Cu2+ [ENT(AN*-->Cu2+)].

Journal Article↗
PubMed2005

Reduction of benzophenone by SmI2: the role of proton donors in determining product distribution.

[reaction: see text] Reduction of benzophenone by SmI2 yields benzopinacol. Addition of proton donors results in an initial increase in the amount of the benzhydrol formed. However, the ratio benzhydrol/benzopinacol reaches a maximum, decreases, and then levels off as the proton donor concentration is further increased. The position of the maximum and its height depend on the proton donor concentration and its kinetic acidity. The momentary concentration of the intermediate radicals governs the product distribution.

Journal Article↗
PubMed1997

Identification of a firefly luciferase active site peptide using a benzophenone-based photooxidation reagent.

Firefly luciferase catalyzes the highly efficient emission of yellow-green light from substrate luciferin by a series of reactions that require MgATP and molecular oxygen. We prepared 2-(4-benzoylphenyl)thiazole-4-carboxylic acid (BPTC), a novel benzophenone-based substrate analog, intending to use it in photoaffinity labeling studies to probe the luciferase active site. Instead, we found that while BPTC was a potent photoinactivating reagent for firefly luciferase, it was not a photoaffinity labeling agent. Using proteolysis, reverse phase high-performance liquid chromatography, tandem high performance liquid chromatography-electrospray ionization mass spectrometry, and Edman sequencing, we identified a single luciferase peptide, 244HHGF247, the degradation of which was directly correlated to luciferase photoinactivation. Results of enzyme kinetics and related studies were consistent with this peptide being at or near the luciferin binding site. Further, peptide model studies and additional investigations on the nature of the photoinactivation process strongly suggested that BPTC catalyzed the formation of singlet oxygen at the active site of the enzyme. We describe here an uncommon example of active site-directed photooxidation of an enzyme by singlet oxygen.

Affinity Labels↗
PubMed2004

Polyisoprenylated benzophenone, garcinol, a natural histone acetyltransferase inhibitor, represses chromatin transcription and alters global gene expression.

Histone acetylation is a diagnostic feature of transcriptionally active genes. The proper recruitment and function of histone acetyltransferases (HATs) and deacetylases (HDACs) are key regulatory steps for gene expression and cell cycle. Functional defects of either of these enzymes may lead to several diseases, including cancer. HATs and HDACs thus are potential therapeutic targets. Here we report that garcinol, a polyisoprenylated benzophenone derivative from Garcinia indica fruit rind, is a potent inhibitor of histone acetyltransferases p300 (IC50 approximately 7 microm) and PCAF (IC50 approximately 5 microm) both in vitro and in vivo. The kinetic analysis shows that it is a mixed type of inhibitor with an increased affinity for PCAF compared with p300. HAT activity-dependent chromatin transcription was strongly inhibited by garcinol, whereas transcription from DNA template was not affected. Furthermore, it was found to be a potent inducer of apoptosis, and it alters (predominantly down-regulates) the global gene expression in HeLa cells.

Acetyltransferases↗
PubMed1998

Photoallergic contact dermatitis due to combined UVB (4-methylbenzylidene camphor/octyl methoxycinnamate) and UVA (benzophenone-3/butyl methoxydibenzoylmethane) absorber sensitization.

In a 71-year-old male Caucasian patient with persistent eczema on light-exposed skin, photocontact allergy was demonstrated to the UV filter substances 4-methylbenzylidene camphor (UVB), octyl methoxycinnamate (UVB), benzophenone-3 (UVA) and butyl methoxydibenzoylmethane (UVA) present in sunscreen products used by the patient over several years. A significantly reduced UVB sensitivity of 25 mJ/cm2 in this patient (normal minimal erythema dose in our laboratory = 70-130 mJ/cm2) was considered an early indication of a persistent light reaction. Topical anti-inflammatory treatment over 2 weeks together with consequent application of a sunscreen containing Mexoryl SX/titanium dioxide led to complete remission. Taking into account the widespread use of the above UV filter substances not only in sun protection products, but also in cosmetics such as antiaging lotions and day care products, the possible risk of allergy to these chemicals has to be taken seriously. The substitution of known photocontact sensitizers in UV filters by photostable compounds and detailed product information are the basis of preventive strategies.

Aged↗
PubMed1986

Identification of novel N-glucuronides in rat bile after administration of 450191-S, a 1H-1,2,4-triazolyl benzophenone derivative.

5-[2-Aminoacetamido)methyl]-1-[p-chloro-2-(o-chlorobenzoyl)phenyl] -N,N-dimethyl-1H-s-triazole-3-carboxamide hydrochloride dihydrate (450191-S) is a ring-opened derivative of 1,4-benzodiazepine, which is activated by desglycylation and subsequent cyclization. After 450191-S administration, rat bile contained three novel conjugates which released active metabolites possessing the 1,4-benzodiazepine structure through beta-glucuronidase hydrolysis. Since the released metabolites have no functional groups to conjugate with glucuronic acid, we speculated that the aglycone might be the ring-opened form of 1,4-benzodiazepine which spontaneously cyclizes after the release of glucuronic acid. This possibility was tested by chemically reducing the ketone group of the ring-opened 1,4-benzodiazepine glucuronate conjugates, which would prevent the spontaneous ring closure reaction after the release of the glucuronic acid moiety. The NaBH4 reduction of the ketone of the benzophenone moiety of the conjugates and subsequent treatment with beta-glucuronidase allowed identification of the reduced aglycones with authentic samples using gas chromatography-mass spectrometry.

Animals↗
PubMed2000

Benzophenone C-glucosides from Polygala telephioides.

Three novel benzophenone C-glucosides, 3'-C-beta-D-glucopyranosyl-2',4',6',3-tetrahydroxy-4-methoxybenzophen one, 3'-C-beta-D-glucopyranosyl-2',4',6'-trihydroxy-3,4-dimethoxybenzophen one and 4'-C-beta-D-glucopyranosyl-2',3',5',6',3-pentahydroxybenzophenone, named telephenones A, B, and C were isolated from the whole plant of Polygala telephioides WILLD and their structures determined by analysis of spectroscopic data.

Glucosides↗
PubMed1985

Effect of 450191-S, a 1H-1,2,4-triazolyl benzophenone derivative, on cerebral content of neuroactive amino acids.

The effect of 450191-S, one of the 1H-1,2,4-triazolyl benzophenone derivatives and possessing benzodiazepine-like anti-anxiety actions, on the content of various amino acids in the mouse brain was examined in comparison with that of nitrazepam. Among the various amino acids examined, only glycine, aspartic acid and alanine showed a statistically significant decrease following the oral administration of 450191-S. The oral administration of nitrazepam also induced a similar decline in the cerebral contents of glycine and alanine. Furthermore, it was found that the administration of Ro 15-1788, a benzodiazepine antagonist, eliminated the 450191-S-induced decline in the cerebral contents of glycine and aspartic acid. These results indicate that the administration of 450191-S induces the decrease of glycine and aspartic acid, neuroactive amino acids, in the brain, possibly via the activation of benzodiazepine receptors.

Amino Acids↗
PubMed1987

Effect of change of hepatic drug-metabolizing activity on plasma concentrations of major metabolites of the new sleep inducer 450191-S, a 1H-1,2,4-triazolyl benzophenone derivative.

Plasma concentrations of the major metabolites of 450191-S, a new sleep inducer which is a 1H-1,2,4-triazolyl benzophenone derivative, were determined in rats. Under the HPLC conditions employed, several major metabolites were detected in plasma, and thus the plasma concentration-time profiles for these metabolites were checked in rats in various states. When the animals were pretreated with high doses of 450191-S (200 or 600 mg/kg for 5 or 3 days, respectively) to induce hepatic drug-metabolizing enzymes, plasma concentrations of the metabolites after oral administration of a dose of 200 mg/kg of 450191-S decreased markedly depending on the induced enzyme activity. Pretreatment of rats with phenobarbital also caused decreased plasma levels of metabolites, which were almost the same as those in 450191-S-pretreatment. On the other hand, administration of beta-naphthoflavone to rats led to higher plasma levels of metabolites, and slower elimination compared with those in the control and 450191-S- or phenobarbital-pretreated rats. These results indicate that plasma levels of metabolites are regulated by the drug-metabolizing enzymes in the liver. It also suggests the participation of some specific forms of cytochrome P-450 in the biotransformation of 450191-S and its metabolites.

Animals↗
PubMed2000

New derivatives of 2-(N-arylmethylideneamine) benzophenone oxime as potential radiopharmaceuticals for brain imaging.

BACKGROUND: The aim of this work was the development of a sufficient method for synthesis and radiolabelling with technetium- 99m a new class of compounds as potential ligands for brain imaging. METHODS: The synthesis of new ligands with the structure of 2-(N-arylmethylideneamine) benzophenone oxime (6-10) based on the cyclocondensation of appropriate 2-aminobenzophenone oxime 1-2 with respective aldehydes 3-4 or ketone 5 in acidic conditions. During our experiments in dependencies from the reaction conditions, compounds with the structure of Schiff's bases (6-10) or 3N-oxides 1,2-dihrydroquinazoline derivatives were obtained. Labelling of compounds 6 or 7 with technetium- 99m was done by stannous chloride reduction according to two methods (in ethyl alcohol or in chloroform) following the radiolabelling method of HM-PAO. The complex (99m)Tc-HM-PAO was the leading compound in our computational calculations with geometrical optimisation of a molecule. Using molecular modelling (semi-empirical method ZINDO) we have determined the electrostatic potential for the obtained ligands. Additionally we have calculated total energy,binding energy, heat of formation and several 3D-QSAR parameters for theoretically possible complexes of (99m)Tc with the obtained ligands. RESULTS: As a result of our experiments a method of a synthesis of new compounds 6 and 7 has been developed. Computational calculations were performed using the HyperChem 4.5 program. These calculations confirmed our hypothesis that only ligand 7 is able to form a complex with (99m)Tc and this complex possesses lipophilic properties. CONCLUSIONS: Complex (99m)Tc-7, due to its lipophilic properties, is a potential radiopharmaceutical for the brain imaging.

Journal Article↗
PubMed1992

Investigations into a new antiarrhythmic substance Z-2-amino-5-chlor-benzophenon-amidin-hydralazin in humans.

Z-2-amino-5-chlor-benzophenon-amidin-hydralazin is a new chemical potential antiarrhythmic substance. The blood levels were investigated after different dosages and forms of administration in patients and volunteers. The determination of the substance can be performed by high-pressure liquid chromatography. In addition the pharmacokinetic parameters were calculated. The pharmacokinetic profile is similar in humans and animals.

Administration, Oral↗
PubMed1984

[Pharmacology of a new sleep inducer, 1H-1,2,4-triazolyl benzophenone derivative, 450191-S (II). Sleep-inducing activity and effect on the motor system].

The sleep-inducing activity and effect on the motor system of the 1H-1,2,4-triazolyl benzophenone derivative 450191-S were examined behaviorally, electroencephalographically and electro-physiologically with various species of animals and were compared with those of diazepam, nitrazepam, estazolam and triazolam. In the rhesus monkey, rabbit and rat with chronically indwelling brain electrodes, 0.6 to 3 mg/kg, p.o. of 450191-S caused a shorter latency of sleep onset, an increase of and a stable continuity of slow wave deep sleep (SWDS) with higher amplitude, and the appearance of clear spindle bursts in the slow wave light sleeping (SWLS) state with little muscle relaxation. Animals treated with nitrazepam and/or estazolam showed a smaller increase in SWDS and its unstable continuity with remarkable disturbance of gait. The doses needed to induce sleep in the rhesus monkey were 0.6 to 1 mg/kg p.o. for 450191-S, 3 mg/kg for nitrazepam, 1 mg/kg for estazolam and 0.3 mg/kg for triazolam. The cat treated with 450191-S showed the phenomena caused by benzodiazepines (BDZ), i.e., behavioral excitation and decrease of frequencies in the hippocampal theta waves. The suppressive effects of 450191-S on the EEG arousal reaction and/or blood pressure elevation induced by hypothalamic stimulation in the rabbit suggested that the inhibitory effects acted on the posterior hypothalamus to the limbic system. The inhibitory effect of 450191-S on the amygdaloid kindling in the rat was as potent as those of diazepam and nitrazepam. Successive daily oral administration of both 3 mg/kg of 450191-S and/or 3 to 6 mg/kg of nitrazepam for 15 days in the rabbit caused slight decrease of SWDS and increase of fast wave (REM) sleep (FWS). During the withdrawal period of both compounds, a slight but insignificant increase in the waking state was noticed for 1 to 2 days, but not a rebound increase of FWS. Intravenously administered 450191-S showed the same action as BDZ on the spinal reflex and the dorsal root potential of the rat; it particularly acted on the crossed extensor reflex in the same manner as the commercial BDZ sleep inducers.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1996

In vitro antiplatelet activity of the carbinol analogue of ketoprofen, 3-(1-methyl-2-hydroxyethyl)-benzophenone.

3-(1-Methyl-2-hydroxyethyl)-benzophenone (F025) is a close structural analogue of ketoprofen, in which the carboxylic acid of ketoprofen is reduced to a carbinol moiety. The in vitro effects of F025 on platelet aggregation, cyclooxygenase and hypotonic NaCl-induced erythrocyte hemolysis were examined in comparison with those of ketoprofen. Although the inhibitory activity of F025 on collagen, arachidonic acid and ADP-induced platelet aggregation was between 2 and 20 times that of ketoprofen in healthy volunteers, guinea pigs, rabbits and rats, F025 had only one-tenth of the inhibitory action of ketoprofen on sheep seminal vesicle cyclooxygenase F025, but not ketoprofen, inhibited hypotonic NaCl-induced erythrocyte hemolysis in guinea pigs. The substantial antiplatelet activity of F025 may be due to membrane stabilization as well as to cyclooxygenase inhibition.

Animals↗
PubMed2007

High-performance liquid chromatography and LC-ESI-MS method for the identification and quantification of two biologically active polyisoprenylated benzophenones xanthochymol and isoxanthochymol in different parts of Garcinia indica.

A reverse-phase high-performance liquid chromatographic method was developed for qualitative and quantitative analysis of xanthochymol (1), and isoxanthochymol (2) in the fruit rinds, leaves and seed pericarps of Garcinia indica with confirmation using PDA detection and electrospray ionization MS. Absorption at 276 nm was chosen as the measuring wavelength at which resolution and baseline separation of compounds (1) and (2) could be obtained. The identity of the above two isomeric compounds (1) and (2) in the samples was unambiguously determined by their respective quasi-molecular ion [M - H]- in ESI-MS. Compounds (1) and (2) were qualitatively and quantitatively analyzed in the above three samples of Garcinia indica. The overall analytical procedure is rapid and reproducible and is considered for the analysis of the above two compounds.

Benzophenones↗