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1.
Chem Biodivers ; 19(10): e202200578, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36006860

RESUMO

Essential oils obtained from different parts of Achillea coarctata species (inflorescences, stem and leaves and the whole aerial part) collected on four different locations in Serbia have been investigated to evaluate the chemical composition and antibacterial activity of isolated oils. The aim of this study was to determine differences in the chemical composition of essential oils obtained from different plant parts and how different type of substrate as well as different climate conditions affect the chemical composition of essential oils. Oxigenated terpenes were reported to be the major constituents in almost all examinated samples with 1,8-cineole, caryophyllene oxide and cis-cadin-4-en-7-ol identified as dominant compounds. Disk diffusion assay was used to determine antibacterial activity against two Gram-positive (Bacillus subtilis subsp. spizizenii ATCC 6633 and Staphylococcus aureus ATCC 6538) and three Gram-negative bacteria (Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Salmonella abony ATCC 6017). The obtained results showed that essential oils obtained from A. coarctata exhibit significant antibacterial activity against tested bacteria strains. The best inhibitory effect was observed against S. aureus, while on the other hand P. aeruginosa showed high level of resistance to almost all examined essential oils.


Assuntos
Achillea , Antibacterianos , Óleos Voláteis , Staphylococcus aureus , Achillea/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Eucaliptol , Cromatografia Gasosa-Espectrometria de Massas , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Compostos Fitoquímicos , Óleos de Plantas/química , Staphylococcus aureus/efeitos dos fármacos , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia
2.
Br J Pharmacol ; 179(13): 3470-3481, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35122240

RESUMO

BACKGROUND AND PURPOSE: Venomous animals express numerous Kunitz-type peptides. The mambaquaretin-1 (MQ1) peptide identified from the Dendroaspis angusticeps venom is the most selective antagonist of the arginine-vasopressin V2 receptor (V2R) and the only unique Kunitz-type peptide active on a GPCR. We aimed to exploit other mamba venoms to enlarge the V2R-Kunitz peptide family and gain insight into the MQ1 molecular mode of action. EXPERIMENTAL APPROACH: We used a bio-guided screening assay to identify novel MQs and placed them phylogenetically. MQs were produced by solid-phase peptide synthesis and characterized in vitro by binding and functional tests and in vivo by diuresis measurement in rats. KEY RESULTS: Eight additional MQs were identified with nanomolar affinities for the V2R, all antagonists. MQs form a new subgroup in the Kunitz family, close to the V2R non-active dendrotoxins and to two V2R-active cobra toxins. Sequence comparison between active and non-active V2R Kunitz peptides highlighted five positions, among which four are involved in V2R interaction and belong to the two large MQ1 loops. We finally determined that eight positions, part of these two loops, interact with the V2R. The variant MQ1-K39A showed a higher affinity for the hV2R, but not for the rat V2R. CONCLUSIONS AND IMPLICATIONS: A new function and mode of action is associated with the Kunitz peptides. The number of MQ1 residues involved in V2R binding is large and may explain its absolute selectivity. MQ1-K39A represents the first step in the improvement of the MQ1 design from a medicinal perspective.


Assuntos
Elapidae , Receptores de Vasopressinas , Animais , Elapidae/metabolismo , Peptídeos/farmacologia , Ratos , Receptores de Vasopressinas/metabolismo , Venenos de Serpentes/farmacologia , Vasopressinas
3.
Nat Prod Res ; 34(13): 1947-1950, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30689406

RESUMO

Chemical composition of the headspace volatiles and essential oils isolated from different parts of Ferulago sylvatica was determined by GC and GC/MS analyses. The results showed that headspace volatiles obtained from the aerial parts and roots were similar regarding the number of identified compounds and main components. However, essential oils obtained from different plant organs showed significant differences in chemical composition. Myrcene was the most abundant component of the inflorescences and shoots volatiles, while α-pinene make up over 50% of the root volatiles. Only three components were identified in the root essential oil with 2,3,6-trimethyl benzaldehyde (92.7%) as the main component. In the shoots sample the terpenoid fractions represented 56% of the oil, unevenly distributed between monoterpenoids and sesquiterpenoids with germacrene D (32.5%) recognized as the main constituent. On the other hand, more than 94% of the inflorescences oils were monoterpenoids with myrcene as the most abundant contributor (29.2%).


Assuntos
Apiaceae/química , Óleos Voláteis/química , Extratos Vegetais/química , Estruturas Vegetais/química , Terpenos/análise , Monoterpenos Acíclicos/análise , Alcenos/análise , Monoterpenos Bicíclicos/análise , Cromatografia Gasosa-Espectrometria de Massas , Monoterpenos/análise , Óleos de Plantas/química , Sérvia , Sesquiterpenos/análise
4.
Chem Biodivers ; 15(1)2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29164790

RESUMO

Eleven species of wild mushrooms which belong to Boletaceae and Russulaceae families were examined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) analysis for the presence of fatty acids. As far as we know, the fatty acid profiles of B. purpureus and B. rhodoxanthus were described for the first time. Twenty-six fatty acids were determined. Linoleic (19.5 - 72%), oleic (0.11 - 64%), palmitic (5.9 - 22%) and stearic acids (0.81 - 57%) were present in the highest contents. In all samples, unsaturated fatty acids dominate. Agglomerative hierarchical clustering was used to display the correlation between the fatty acids and their relationships with the mushroom species. Based on the fatty acids profile in the samples, the mushrooms can be divided into two families: Boletaceae and Russulaceae families, using cluster analysis.


Assuntos
Agaricales/química , Ácidos Graxos/análise , Cromatografia Gasosa , Espectrometria de Massas , Especificidade da Espécie
5.
Nat Prod Res ; 32(3): 331-334, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28697622

RESUMO

Phytochemical analysis by GC and GC/MS of the essential oil samples obtained from fresh shoots and flowers of Saponaria officinalis L. allowed the identification of 96 components in total, comprising 94.7% and 86.0% of the total oils compositions, respectively. Regarding the shoots essential oil, the major of 87 identified volatile compounds were phytol (14.1%), tricosane-6,8-dione (13.4%), patchouli alcohol (7.9%) and tricosane (7.2%), whereas patchouli alcohol (20.0%), heneicosane (11.5%) and tricosane (8.4%) were dominant among the 66 volatiles in the flower oil. Nonterpenoid compounds had the highest contribution in S. officinalis shoots essential oil (53.7%), while in the flower oil, constituents were almost evenly distributed between the oxygenated sesquiterpenoid (41.2%) and nonterpenoid compounds (39.5%).


Assuntos
Compostos Fitoquímicos/análise , Saponaria/química , Flores/química , Cromatografia Gasosa-Espectrometria de Massas , Óleos Voláteis/análise , Óleos Voláteis/química , Brotos de Planta/química , Sesquiterpenos/análise , Terpenos/análise
6.
Environ Sci Pollut Res Int ; 24(18): 15609-15621, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28523616

RESUMO

Samples of roots and spatial soils of native Rubus fruticosus L. were collected from the spots positioned at different distances from the copper smelter and city heating plants in the industrial zone of the town of Bor (Serbia) and subjected to chemical analyses in order to determine the content of several heavy metals, and 15 priority polycyclic aromatic hydrocarbons (PAHs). In this study, the results for 9 low and medium molecular weight PAHs (LMW and MMW PAHs) are represented and processed using the calculation of bio-concentration factors and statistical methods such as hierarchical cluster analysis and Pearson's correlation study with the aim of investigating the plant capabilities for their uptake from the soil and later accumulation into the root tissue, under the hostile circumstances of multiple contamination. The obtained data revealed different accumulation rates for the investigated PAHs and showed that in several cases, the contents of root PAHs were under the strong influence of present contaminants such as soil copper and some soil PAHs, indicating at the same time that R. fruticosus can regulate the processes of LMW and MMW PAHs extraction/accumulation using different mechanisms, depending on the existing environmental circumstances. The used mechanisms could be exploited in phytoremediation methods based not only on the extraction and concentration of PAHs in plant roots but also on PAH degradation or stabilization in the soil. Also, the results of this study confirmed that, except in the case of naphthalene and fluoranthene, there was no PAH pollution, which originated solely from the industrial zone.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Rubus , Poluentes do Solo/farmacocinética , Cidades , Cobre , Monitoramento Ambiental , Mineração , Peso Molecular , Sérvia , Solo
7.
Chem Biodivers ; 14(5)2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28273389

RESUMO

The present study reports the chemical composition of the headspace volatiles (HS) and essential oils obtained from fresh Chaerophyllum aromaticum root and aerial parts in full vegetative phase, as well as biological activities of their essential oils and MeOH extracts. In HS samples, the most dominant components were monoterpene hydrocarbons. On the other hand, the essential oils consisted mainly of sesquiterpenoids, representing 73.4% of the root and 63.4% of the aerial parts essential oil. The results of antibacterial assay showed that the aerial parts essential oil and MeOH extract have no antibacterial activity, while the root essential oil and extract showed some activity. Both of the tested essential oils exhibited anticholinesterase activity (47.65% and 50.88%, respectively); MeOH extract of the root showed only 8.40% inhibition, while aerial part extract acted as an activator of cholinesterase. Regarding the antioxidant activity, extracts were found to be more effective than the essential oils.


Assuntos
Apiaceae/química , Óleos Voláteis/química , Extratos Vegetais/química , Anti-Infecciosos , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Inibidores da Colinesterase/isolamento & purificação , Inibidores da Colinesterase/farmacologia , Monoterpenos/isolamento & purificação , Sesquiterpenos/isolamento & purificação
8.
Nat Prod Res ; 31(7): 857-860, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28029061

RESUMO

The aim of this work was to determine the chemical composition of the ether, ethyl acetate and dichloromethane extracts of Ramalina capitata by GC-FID and GC-MS for the first time. The main identified components in the ether, ethyl acetate and dichloromethane extracts were everninic acid (24.7, 33.7 and 22.2%), orcinol (25.8, 16.7 and 11.9%), orcinol monomethyl ether (11.6, 7.6 and 4.8%), 3-methylorsellinic acid (10.2, 7.1 and 9.0%) and usnic acid (4.4, 8.2 and 25.8%), respectively. Considerable amount (10.4%) of 2-hydroxy-4-methoxy-3,5,6-trimethylbenzoic acid was detected in ethyl acetate extract. Additionally, palmitic acid, linoleic acid, oleic acid and stearic acid and their esters were observed in the dichloromethane and ethyl acetate extracts in the range of 4.1-0.1%, while their amount was below 0.05% in the ether extract. According to the results reported here R. capitata predominantly biosynthesises derivatives of orcinol and, in much lesser extent, derivatives of ß-orcinol.


Assuntos
Ascomicetos/química , Benzofuranos , Cromatografia Gasosa , Ionização de Chama , Cromatografia Gasosa-Espectrometria de Massas , Metanol , Resorcinóis , Solventes
9.
Nat Prod Commun ; 11(4): 543-5, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27396214

RESUMO

This study reports the essential oil composition and headspace volatiles profile of Achillea coarctata Poir. from Serbia. The inflorescences, stems and leaves, and the aerial parts of A. coarctata were analyzed separately. Germacrene D, α-terpineol and 1,8-cineole were the main constituents of the aerial parts essential oil; 1,8-cineole, cis-cadin-4-en-7-ol and α-terpineol were the most dominant compounds in the inflorescence essential oil, while the most abundant components in the stem and leaf oil were germacrene D, cis-cadin-4-en-7-ol and ledol. The percentages of monoterpenoids and sesquiterpenoids in the aerial parts were the same, while there were differences in distribution of these compound classes in inflorescence and stem and leaf essential oils. The major components of the headspace volatiles were the same for aerial parts, inflorescence and stem and leaves: 1,8-cineole, ß-pinene and α-pinene.


Assuntos
Achillea/química , Óleos Voláteis/química , Compostos Orgânicos Voláteis/química , Sérvia
10.
Sci Total Environ ; 562: 561-570, 2016 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-27110970

RESUMO

In this work, the samples of roots and soils from the rooting zone of wild blackberry were collected from the urban-industrial and rural locations near "The Copper Mining and Smelting Complex Bor" (Serbia); they were analyzed by gas chromatographic-mass spectrometric method to determine the content of high-molecular weight polycyclic aromatic hydrocarbons (HMW PAHs). The obtained results were further processed using bio-concentration factor, Pearson's correlation study and hierarchical cluster analysis with the aim of investigating if they may be in favor of wild blackberry as a suitable plant for biomonitoring or phytoremediation purposes. In spite of the fact that numerous complex factors can affect the assimilation and accumulation of PAHs in plants, the obtained data expressed clearly many interesting specifics related to HMW PAH accumulation in roots of wild blackberry that naturally grows in an area, which is heavily polluted by heavy metals. The accumulation of individual PAH compounds in plant roots was at different level. The most abundant compound in all plant samples was benzo[a]pyrene and based on the results obtained for this environmental indicator of carcinogenic PAHs, it was possible to make several central conclusions: wild blackberry showed an excellent potential for its extraction from the soil and further accumulation in root tissues which indicate that this plant species may be applied in phytoremediation procedures based on mechanisms such as phytoextraction/phytoaccumulation in roots; phytostabilization and rhizodegradation are also possible as remediation mechanisms; utilization of plant roots in soil monitoring is possible but in this case, only the combination with soil data can provide correct information.


Assuntos
Raízes de Plantas/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Rubus/química , Poluentes do Solo/análise , Biodegradação Ambiental , Monitoramento Ambiental , Raízes de Plantas/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Rubus/metabolismo , Sérvia , Poluentes do Solo/metabolismo
11.
Nat Prod Commun ; 10(8): 1439-41, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26434137

RESUMO

The present study reports the chemical composition on the essential oil obtained from fresh roots, stems, inflorescences and fruits of Chaerophyllum temulum. In all samples, except the roots, the most dominant components were sesquiterpene hydrocarbons. (Z)-Falcarinol was the principal constituent of the root essential oils (61.7% at the flowering stage and 62.3% at the fruiting stage). The blossom oil was dominated by (Z,E)-α-famesene (23.4%), (E)-ß-farnesene (9.0%) and germacrene D-4-ol (9%), whereas the oil from the fruit had germacrene D-4-ol (27.6%) as its main compound, accompanied by (Z,E)-α-famesene (13.4%). Germacrene D was the most abundant component of the stem essential oil (38.4% at the flowering stage and 32.5% at the fruiting stage). The obtained results show that the qualitative composition of the oil depends on the part of the plant which is analyzed, while the quantitative composition of the main components depends on the growing stage of the plant.


Assuntos
Apiaceae/química , Óleos Voláteis/química , Óleos de Plantas/química , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química
12.
Nat Prod Commun ; 10(4): 661-4, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25973504

RESUMO

The present study for the first time reports the chemical composition of the endemic Balkan parsnip Pastinaca hirsuta Pancic essential oil and headspace (HS) volatiles, obtained from fresh roots, stems, flowers and fruits, as well as fresh fruits n-hexane and diethyl ether extracts. According to GC-MS and GC-FID analyses, ß-Pinene was one of the major components of the root and stem HS volatiles (50.6-24.1%). (E)-ß-Ocimene was found in a significant percentage in the stem and flowers HS volatiles (31.6-57.3%). The most abundant constituent of the fruit HS, flower and fruit essential oils and both extracts was hexyl butanoate (70.5%, 31.1%, 80.4%, 47.4% and 52.7%, respectively). Apiole, accompanied by myristicin and (Z)-falcarinol, make up over 70% of the root essential oils. γ-Palmitolactone was the major component of the stem essential oils (51.9% at the flowering stage and 45.7% at the fruiting stage). Beside esters as dominant compounds, furanocoumarins were also identified in extracts. (Dis)similarity relations of examined plant samples were also investigated by the agglomerative hierarchical cluster analysis. The obtained results show there is difference in the composition of volatile components from different plant organs, while the stage of growth mainly affects the quantitative volatiles composition.


Assuntos
Óleos Voláteis/química , Pastinaca/química , Extratos Vegetais/química , Óleos de Plantas/química
13.
Nat Prod Commun ; 9(11): 1609-12, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25532293

RESUMO

Analysis of head space volatiles (HSV) and hydrodistilled essential oils (EO) of the above-ground parts of Thymus glabrescens Willd., T. praecox Opiz subsp. jankae (Celak.) Jalas (from two localities) and T. pulegoides L. was made by GC-FID and GC-MS. This is the first report on the headspace volatiles composition of T. glabrescens and T. pulegoides. The most abundant compound of T. glabrescens HSV was p-cymene (27.8%) followed by γ-terpinene (18.4%), while thymol (55.4%) and geraniol (10.5%) were the most abundant in the corresponding EO. T. praecox subsp. jankae EO from Serbia was characterized by (E)-caryophyllene (14.6%) and thymol (10.7%), which is substantially different from that of Bulgarian T. praecox subsp. jankae, which contained a-terpinyl acetate (20.1%) and linalool (17.7%) as its main components. The dominating components of the Serbian and Bulgarian T. praecox subsp. jankae HSV were α-pinene (29.4% and 18.6%, respectively), myrcene (12.1% and 23.2%, respectively), limonene (7.5% and 17.8%, respectively) and ß-pinene (11.7% and 7.6%, respectively). Linalyl acetate predominated in T. pulegoides EO and HSV, representing 40.0% and 42.4% (respectively) of the total peak area. The chemical composition of the essential oils of the examined Thymus species could not be attributed to any particular recorded chemotype of T. glabrescens, T. praecox and T. pulegoides.


Assuntos
Óleos Voláteis/análise , Thymus (Planta)/química , Monoterpenos Acíclicos , Alcenos/análise , Monoterpenos Bicíclicos , Monoterpenos Cicloexânicos , Cicloexenos/análise , Cimenos , Cromatografia Gasosa-Espectrometria de Massas , Limoneno , Monoterpenos/análise , Terpenos/análise , Timol/análise
14.
Nat Prod Commun ; 9(2): 271-2, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24689308

RESUMO

The essential oil of the Balkan endemic species, Angelica pancicii, obtained by hydrodistillation, was analyzed by GC and GC-MS, applying the liquid injection mode. These results were compared with the chemical composition of volatiles achieved by the "headspace" injection mode, followed by GC and GC-MS (HS-GC-MS). A total of 40 compounds were identified in the essential oil (98.8% of the total oil) and 44 by HS-GC-MS (99.8% of the total oil). The most abundant class of compounds in both cases was monoterpenoids, which formed 92.7% of the essential oil (97.7% by HS-GC-MS) of total identified compounds. The major components in both cases were beta-phellandrene (54.9% and 60.1%, respectively), alpha-pinene (14.5% and 20.1%, respectively) and alpha-phellandrene (4.5% and 4.3%, respectively).


Assuntos
Angelica/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Óleos Voláteis/análise
15.
Chem Biodivers ; 11(1): 140-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24443434

RESUMO

The chemical composition and the antimicrobial activity of the essential oil isolated from the aerial parts of Hypericum maculatum Crantz were determined. In total, 109 compounds were identified, with germacrene D (21.5%), nonane (6.5%), (E)-ß-farnesene (5.3%), δ-cadinene (4.5%), and ledol (4.4%) as the main constituents. The chemical compositions of this oil and of four previously studied H. maculatum oils were compared using multivariate statistical analyses, viz., agglomerative hierarchical cluster and principal component analyses. Based on the results, the interrelationship among the hitherto studied H. maculatum oil samples, including the oil characterized here, was discussed. The study of the antimicrobial potential of the oil against five bacterial and two fungal strains showed that the oil had mainly moderate antimicrobial effects.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Hypericum/química , Óleos Voláteis/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Relação Estrutura-Atividade
16.
Nat Prod Commun ; 8(1): 109-12, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23472471

RESUMO

Three lichen depsidones, physodalic acid (1), physodic acid (2), and 3-hydroxy physodic acid (3), were isolated from Hypogymnia physodes diethyl ether extract using column chromatography, and their structures determined by comparing their UV, 1H and 13C NMR spectroscopic and MS data with those given in the literature, as well as with data computed by CHEM draw ultra 11 software. The contents of 1, 2 and 3 were determined in the methanol (ME), acetone (AE), and diethyl ether (EE) extracts using reversed-phase high performance liquid chromatography with photodiode array detection. The extracts, isolated depsidones 1-3 and EE fraction F23 (consisting of 90% 2 and 3, in the ratio 5.5: 1) were evaluated for their in vitro effects on chromosome aberrations in peripheral human lymphocytes using the cytochalasin-B blocked micronucleus (CBMN) assay in doses of 1 microg/mL and 2 microg/mL of final culture solution. The frequency of MN was scored in binucleated cells, and nuclear proliferation index was calculated. It was found that 1, 2, 3, F23, and EE at 1.0 microg/mL exerted a beneficial effect on lymphocyte cells giving a significant decrease of the frequency of MN in comparison with the positive control Amifostin WR-2721.Among the tested depsidones at a concentration of 1 microg/mL, 3 exhibited the most prominent effect decreasing the frequency of MN by 30.3%, followed by 2 (28.2%) and 1 (22.0%). The extracts were less effective than the isolated depsidones.


Assuntos
Dibenzoxepinas/farmacologia , Líquens/química , Linfócitos/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Dibenzoxepinas/isolamento & purificação , Avaliação Pré-Clínica de Medicamentos , Humanos
17.
Sensors (Basel) ; 12(4): 4181-310, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22666026

RESUMO

Base stations represent the main contributor to the energy consumption of a mobile cellular network. Since traffic load in mobile networks significantly varies during a working or weekend day, it is important to quantify the influence of these variations on the base station power consumption. Therefore, this paper investigates changes in the instantaneous power consumption of GSM (Global System for Mobile Communications) and UMTS (Universal Mobile Telecommunications System) base stations according to their respective traffic load. The real data in terms of the power consumption and traffic load have been obtained from continuous measurements performed on a fully operated base station site. Measurements show the existence of a direct relationship between base station traffic load and power consumption. According to this relationship, we develop a linear power consumption model for base stations of both technologies. This paper also gives an overview of the most important concepts which are being proposed to make cellular networks more energy-efficient.

18.
Proc Natl Acad Sci U S A ; 107(10): 4746-51, 2010 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-20173092

RESUMO

To identify molecules that could enhance sweetness perception, we undertook the screening of a compound library using a cell-based assay for the human sweet taste receptor and a panel of selected sweeteners. In one of these screens we found a hit, SE-1, which significantly enhanced the activity of sucralose in the assay. At 50 microM, SE-1 increased the sucralose potency by >20-fold. On the other hand, SE-1 exhibited little or no agonist activity on its own. SE-1 effects were strikingly selective for sucralose. Other popular sweeteners such as aspartame, cyclamate, and saccharin were not enhanced by SE-1 whereas sucrose and neotame potency were increased only by 1.3- to 2.5-fold at 50 microM. Further assay-guided chemical optimization of the initial hit SE-1 led to the discovery of SE-2 and SE-3, selective enhancers of sucralose and sucrose, respectively. SE-2 (50 microM) and SE-3 (200 microM) increased sucralose and sucrose potencies in the assay by 24- and 4.7-fold, respectively. In human taste tests, 100 microM of SE-1 and SE-2 allowed for a reduction of 50% to >80% in the concentration of sucralose, respectively, while maintaining the sweetness intensity, and 100 microM SE-3 allowed for a reduction of 33% in the concentration of sucrose while maintaining the sweetness intensity. These enhancers did not exhibit any sweetness when tasted on their own. Positive allosteric modulators of the human sweet taste receptor could help reduce the caloric content in food and beverages while maintaining the desired taste.


Assuntos
Receptores Acoplados a Proteínas G/metabolismo , Edulcorantes/farmacologia , Papilas Gustativas/efeitos dos fármacos , Paladar/efeitos dos fármacos , Regulação Alostérica , Linhagem Celular , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Pirimidinas/química , Pirimidinas/farmacologia , Receptores Acoplados a Proteínas G/genética , Sacarose/administração & dosagem , Sacarose/análogos & derivados , Sacarose/química , Sacarose/farmacologia , Edulcorantes/administração & dosagem , Edulcorantes/química , Papilas Gustativas/metabolismo , Tiofenos/química , Tiofenos/farmacologia
20.
J Am Chem Soc ; 128(9): 2859-72, 2006 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-16506764

RESUMO

The molecular structure of azaspiracid-1, a neurotoxin isolated from mussels, has been elucidated by total synthesis which also enriched its supplies. The degradatively derived fragments of this marine biotoxin, compounds 5 (EFGHI), 6 (FGHI), and 40 (ABCD), were matched with synthetic materials, thus confirming their structural identities. Based on this detective work, a new structure of azaspiracid-1 (i.e., 1) was proposed and constructed by total synthesis. The final strategy for the total synthesis of azaspiracid-1 featured a dithiane anion (C(21)-C(27) fragment) reacting with a pentafluorophenol ester (C(1)-C(20) fragment) followed by a Stille-type union of an advanced allylic acetate substrate (C(1)-C(27) fragment) with a vinyl stannane as the main coupling processes to assemble the carbon skeleton of the molecule. In addition to the total synthesis of azaspiracid-1 (1), the syntheses of its C(1)-C(20) epimer (2) and of several truncated analogues for biological investigations are described.


Assuntos
Toxinas Marinhas/química , Toxinas Marinhas/síntese química , Compostos de Espiro/química , Compostos de Espiro/síntese química , Animais , Bivalves/química , Estereoisomerismo
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