Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 699
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Nat Prod Rep ; 41(7): 977-989, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38284321

RESUMO

Covering: up to 2023Conjugated polyynes are natural compounds characterized by alternating single and triple carbon-carbon bonds, endowing them with distinct physicochemical traits and a range of biological activities. While traditionally sourced mainly from plants, recent investigations have revealed many compounds originating from bacterial strains. This review synthesizes current research on bacterial-derived conjugated polyynes, delving into their biosynthetic routes, underscoring the variety in their molecular structures, and examining their potential applications in biotechnology. Additionally, we outline future directions for metabolic and protein engineering to establish more robust and stable platforms for their production.


Assuntos
Bactérias , Poli-Inos , Bactérias/metabolismo , Poli-Inos/química , Poli-Inos/metabolismo , Poli-Inos/farmacologia , Estrutura Molecular , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Vias Biossintéticas , Biotecnologia/métodos
2.
Langmuir ; 40(33): 17613-17621, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39120008

RESUMO

Dopamine (DA), a neurotransmitter, plays a crucial role in regulating motor functions and emotions and can serve as a marker for several diseases. In this study, we report a highly sensitive polydiacetylenes (PDA)-based dual-output sensor for dopamine detection in both solution and solid phases that was developed by modifying PDA liposomes with boronic acid groups at the termini. This sensor exploits the high affinity between the catechol residue of dopamine and the -B(OH)2 group of the PDA-based probe (PDA-PhBA) to form boronate ester bonds, causing a stress-induced blue-to-red color change along with a steady increase in fluorescence response at λmax 622 nm. The PDA-PhBA-based sensor displays high sensitivity toward dopamine with low limit of detection of 6.2 ppb in colorimetric analysis and 0.6 ppb in fluorimetric measurements, demonstrating its dual optical output ability. The sensor works well for adrenaline, another catecholamine, with similar efficacy. Its practical applicability was validated by the successful recovery of trace level dopamine in blood serum and real water samples. Additionally, immobilizing PDA-PhBA liposomes in sodium alginate produced PDA beads for the solid-phase detection of dopamine with an limit of detection (LOD) of 59 nM (9.0 ppb) in colorimetric detection using a smartphone for capturing images and ImageJ software for analysis.


Assuntos
Dopamina , Lipossomos , Polímero Poliacetilênico , Lipossomos/química , Dopamina/análise , Dopamina/sangue , Polímero Poliacetilênico/química , Limite de Detecção , Colorimetria/métodos , Polímeros/química , Poli-Inos/química , Soluções
3.
J Org Chem ; 89(8): 5715-5725, 2024 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-38593068

RESUMO

Some bacteria produce "bacterial polyynes" bearing a conjugated C≡C bond that starts with a terminal alkyne. Ergoynes A and B have been reported as sulfur-containing metabolites from Gynuella sunshinyii YC6258. These compounds were thought to be formed by cycloaddition between a bacterial polyyne (named Gs-polyyne) and l-ergothioneine. The biosynthetic gene clusters (BGCs), which may contribute to their synthesis, were present in the YC6258 genome. The biosynthetic origin of Gs-polyyne is interesting considering its rare 2-isopentyl fatty acyl skeleton. Here, the structures and biosynthesis of Gs-polyyne and ergoynes were verified by analytical, chemical, and genetic techniques. In the YC6258 extract, which was prepared considering their instability, Gs-polyyne was detected as a major LC peak, and ergoynes were not detected. The NMR data of the isolated Gs-polyyne contradicted the proposed structure and identified it as the previously reported protegenin A. The expression of Gs-polyyne BGC in Escherichia coli BL21(DE3) also yielded protegenin A. The cyclization between protegenin A and l-ergothioneine did not proceed during sample preparation; a base, such as potassium carbonate, was required. Overall, Gs-polyyne was identified as protegenin A, while ergoynes were determined to be artifacts. This cyclization may provide a derivatization to stabilize polyynes or create new chemical space.


Assuntos
Ergotioneína , Gammaproteobacteria , Poli-Inos , Alcinos , Bactérias
4.
Macromol Rapid Commun ; 45(6): e2300628, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38227809

RESUMO

A rare asymmetric bicyclic polymer containing different length of conjugated polyacetylene segments is synthesized by metathesis cyclopolymerization-mediated blocking-cyclization technique. The size of each single ring differs from each other, and the unique cyclic polymer topology is controlled by adjusting the feed ratio of monofunctional monomer to catalyst. The topological difference between linear and bicyclic polymers is confirmed by several techniques, and the visualized morphology of asymmetric bicyclic polymer is directly observed without tedious post-modification process. The photoelectric and thermal properties of polymers are investigated. This work expands the pathway for the derivation of cyclic polymers, and such unique topological structure enriches the diversity of cyclic polymer classes.


Assuntos
Polímeros , Poli-Inos , Polímero Poliacetilênico , Ciclização , Polímeros/química , Catálise
5.
Solid State Nucl Magn Reson ; 133: 101959, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39213800

RESUMO

In this work, we elucidated the structural organization of stimuli-responsive peptide-polydiacetylene (PDA) conjugates that can self-assemble as 1D nanostructures under neutral aqueous conditions. The amino acid sequences bear positively or negatively charged domains at the periphery of the peptide segments to promote solubility in water while also driving assembly of the individual and combined components into ß-sheets. The photopolymerization of PDA, as well as the sensitivity of the resulting optical properties of the polymeric material to external stimuli, highly depends on the structural organization of the assembly of amphiphilic peptide-diacetylene units into 1D-nanostructures. Solid-state NMR measurements on 13C-labeled and 15N-labeled samples show that positively charged and negatively charged peptide amphiphiles are each capable of self-assembly, but self-assembly favors antiparallel ß-sheet structure. When positively and negatively charged peptide amphiphiles interact in stoichiometric solutions, cooperative coassembly dominates over self-assembly, resulting in the desired parallel ß-sheet structure with a concomitant increase in structural order. These results reveal that rational placement of oppositely charged residues can control ß-strand organization in a peptide amphiphile coassembly, which would have implications on the adaptive properties of stimuli-responsive biomaterials such as the peptide-PDAs studied here.


Assuntos
Peptídeos , Polímero Poliacetilênico , Peptídeos/química , Polímero Poliacetilênico/química , Conformação Proteica em Folha beta , Tensoativos/química , Espectroscopia de Ressonância Magnética , Poli-Inos/química , Polímeros/química , Nanoestruturas/química
6.
Chem Biodivers ; 21(3): e202301762, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38263615

RESUMO

Artemisia pallens Wall. ex DC (Asteraceae) is cultivated for the production of high-value essential oil from its aerial biomass. In this study, the chemical composition of the root (crop-residue) essential oil was investigated for the first time, using column-chromatography, GC-FID, GC-MS, LC-QTOF, and NMR techniques, which led to the identification of twenty constituents, with isolation of (E)-2-(2',4'-hexadiynylidene)-1,6-dioxaspiro [4.5]dec-3-ene (D6). The D6 was evaluated in vitro for neuroinflammation and acetylcholinesterase inhibitory potential. It showed inhibition of neuroinflammation in a concentration-dependent manner with significant inhibition of pro-inflammatory cytokines (TNF-α and IL-6) in LPS-stimulated BV2 microglial cells. D6 did not have any significant effect on the viability of the cells at the therapeutic concentrations. D6 also has shown acetylcholinesterase inhibitory potential (51.90±1.19 %) at the concentration of log 106  nM. The results showed that D6 has a potential role in the resolution of neuroinflammation, and its acetylcholinesterase inhibitory potential directs further investigation of its role in the management of Alzheimer's disease-related pathogenesis.


Assuntos
Artemisia , Furanos , Óleos Voláteis , Compostos de Espiro , Acetilcolinesterase , Éter , Poli-Inos , Doenças Neuroinflamatórias , Óleos Voláteis/química , Artemisia/química
7.
Mikrochim Acta ; 191(7): 397, 2024 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-38877314

RESUMO

A fluorescence biosensor for determination of aflatoxin B1 (AFB1) based on polydiacetylene (PDA) liposomes and exonuclease III (EXO III)-assisted recycling amplification was developed. The AFB1 aptamer partially hybridizes with complementary DNA (cDNA), which is released upon recognition of AFB1 by the aptamer. Subsequently, the cDNA hybridizes with hairpin H to form double-stranded DNA that undergoes digestion by EXO III, resulting in the cyclic release of cDNA and generation of capture DNA for further reaction. The capture DNA then hybridizes with probe modified on PDA liposomes, leading to aggregation of liposomes and subsequent fluorescence production. This strategy exhibited a limit of detection of 0.18 ng/mL within the linear range 1-100 ng/mL with a determination coefficient > 0.99. The recovery ranged from 92.81 to 106.45%, with relative standard deviations (RSD) between 1.73 and 4.26%, for corn, brown rice, peanut butter, and wheat samples. The stability, accuracy, and specificity of the method demonstrated the applicability for real sample analysis.


Assuntos
Aflatoxina B1 , Técnicas Biossensoriais , Exodesoxirribonucleases , Limite de Detecção , Lipossomos , Polímero Poliacetilênico , Polímero Poliacetilênico/química , Lipossomos/química , Exodesoxirribonucleases/química , Exodesoxirribonucleases/metabolismo , Técnicas Biossensoriais/métodos , Aflatoxina B1/análise , Aptâmeros de Nucleotídeos/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Poli-Inos/química , Espectrometria de Fluorescência/métodos , Zea mays/química , Triticum/química , Oryza/química , Polímeros/química , Contaminação de Alimentos/análise
8.
Molecules ; 29(15)2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39124952

RESUMO

Human DNA topoisomerase I (Topo I) is an essential enzyme in regulating DNA supercoiling during transcription and replication, and it is an important therapeutic target for anti-tumor agents. Bidens pilosa L. is a medicinal herb that is used as a folk medicine for cancers in China. A new flavonoid (1) and a new polyacetylene (20), along with eighteen flavonoids (2-19) and nine polyacetylenes (21-29), were isolated and identified from the methanol extract of the whole plant of B. pilosa, and some of the compounds (4, 5, 6 and 7) exhibited potent cytotoxicity against a panel of five human cancer cell lines. The DNA relaxation assay revealed that some flavonoids and polyacetylenes exerted inhibitory activities on human DNA Topo I, among them compounds 1, 2, 5, 6, 7, 8, 15, 19, 20, 22, and 24 were the most active ones, with IC50 values of 393.5, 328.98, 145.57, 239.27, 224.38, 189.84, 89.91, 47.5, 301.32, 178.03, and 218.27 µM, respectively. The structure-activity analysis of flavonoids was performed according to the results from the Topo I inhibition assay. The DNA content analysis revealed that 5, 6, and 7 potently arrested cell cycle at the G1/S and G2/M phases in human colon cancer cell DLD-1 depending on the concentration of the inhibitors. The levels of protein expression related to the G1/S and G2/M cell cycle checkpoints were in accordance with the results from the DNA content analysis. These findings suggest that flavonoids are one of the key active ingredients accounting for the anti-tumor effect of B. pilosa.


Assuntos
Bidens , DNA Topoisomerases Tipo I , Flavonoides , Poli-Inos , Inibidores da Topoisomerase I , Humanos , Flavonoides/farmacologia , Flavonoides/química , Flavonoides/isolamento & purificação , Bidens/química , DNA Topoisomerases Tipo I/metabolismo , Linhagem Celular Tumoral , Inibidores da Topoisomerase I/farmacologia , Inibidores da Topoisomerase I/química , Inibidores da Topoisomerase I/isolamento & purificação , Poli-Inos/farmacologia , Poli-Inos/química , Poli-Inos/isolamento & purificação , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação
9.
Acc Chem Res ; 55(24): 3616-3630, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36484500

RESUMO

The formation and study of molecules that model the sp-hybridized carbon allotrope, carbyne, is a challenging field of synthetic physical organic chemistry. The target molecules, oligo- and polyynes, are often the preferred candidates as models for carbyne because they can be formed with monodisperse lengths as well as defined structures. Despite a simple linear structure, the synthesis of polyynes is often far from straightforward, due in large part to a highly conjugated framework that can render both precursors and products highly reactive, i.e., kinetically unstable. The vast majority of polyynes are formed as symmetrical products from terminal alkynes as precursors via an oxidative, acetylenic homocoupling reaction based on the Glaser, Eglinton-Galbraith, and Hay reactions. These reactions are very efficient for the synthesis of shorter polyynes (e.g., hexaynes and octaynes), but yields often drop dramatically as a function of length for longer derivatives, usually starting with the formation of decaynes. The most effective approach to circumvent unstable precursors and products has been through the incorporation of sterically demanding end groups that serve to "protect" the polyyne skeleton. This approach was arguably identified in the early 1950s by Bohlmann and co-workers with the synthesis of tBu-end-capped polyynes. During the next 50 years, a polyyne with 14 contiguous alkyne units remained the longest isolated derivative until 2010, when the record was extended to 22 alkyne units. The record length was broken again in 2020, when a polyyne consisting of 24 alkynes was isolated and characterized. Beyond polyynes, there have been several reports describing the potential synthesis of carbyne, but conclusive characterization and proof of structure have been tenuous. The sole example of synthetic carbyne arises from synthesis within carbon nanotubes, when chains of thousands of sp carbon atoms have been linked to form polydisperse samples of carbyne. Thus, model compounds for carbyne, the polyynes, remain the best means to examine and predict the experimental structure and properties of this carbon allotrope.This Account will discuss the general synthesis of polyynes using homologous series of polyynes with up to 10 alkyne units as examples (decaynes). The limited number of specific syntheses of series with longer polyynes will then be presented and discussed in more detail based on end groups. The monodisperse polyynes produced from these synthetic efforts are then examined toward providing our best extrapolations for the expected characteristics for carbyne based on 13C NMR spectroscopy, UV-vis spectroscopy, X-ray crystallography, and Raman spectroscopy.


Assuntos
Nanotubos de Carbono , Poli-Inos , Humanos , Poli-Inos/química , Alcinos/química , Carbamatos
10.
Biomacromolecules ; 24(9): 4051-4063, 2023 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-37552220

RESUMO

The tunability of chromatic phases adapted by chromogenic polymers such as polydiacetylene (PDA) is key to their utility for robust sensing applications. Here, we investigated the influence of charged peptide interactions on the structure-dependent thermochromicity of amphiphilic PDAs. Solid-state NMR and circular dichroism analyses show that our oppositely charged peptide-PDA samples have distinct degrees of structural order, with the coassembled sample being in between the ß-sheet-like positive peptide-PDA and the relatively disordered negative peptide-PDA. All solutions exhibit thermochromicity between 20 and 80 °C, whereby the hysteresis of the blue, planar phase is much larger than that of the red, twisted phase. Resonance Raman spectroscopy of films demonstrates that only coassemblies with electrostatic complementarity stabilize coexisting blue and red PDA phases. This work reveals the nature of the structural changes responsible for the thermally responsive chromatic transitions of biomolecule-functionalized polymeric materials and how this process can be directed by sequence-dictated electrostatic interactions.


Assuntos
Nanoestruturas , Poli-Inos , Poli-Inos/química , Polímero Poliacetilênico , Polímeros/química , Peptídeos
11.
J Org Chem ; 88(13): 7940-7952, 2023 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-37267218

RESUMO

The substituent effect (SE) is one of the most important topics in organic chemistry and related fields, and Hammett constants (σ) are commonly used to describe it. The results of the computational studies carried out for Y-R-X systems (reaction sites Y = NO2, O-; substituents X = NO2, CN, Cl, H, OH, NH2; spacers R = polyene, polyyne, acene with n = 1-5 repeatable units) show that the substituent properties depend significantly on n, the type of R, and Y. Results of the analysis of the substituent effect stabilization energy and geometrical parameters of the Y-R-X systems reveal that (i) the SE strength and its inductive and resonance components decay with the increase in spacer length, its weakening depends on the Y and R type; quantitative relations describing decay are presented; (ii) the ratio between inductive and resonance effect strength changes with n and depends on Y; (iii) differences in the substituents' properties are examples of reverse SE; (iv) in general, structural parameters are mutually well correlated as well as with the SE descriptors; (v) due to the strong O- resonance effect, the changes in π-electron delocalization within R are well correlated with the SE strength only for Y = O- systems.


Assuntos
Elétrons , Dióxido de Nitrogênio , Poli-Inos
12.
J Org Chem ; 88(23): 16280-16291, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37947517

RESUMO

Bacteria in certain genera can produce "bacterial polyynes" that contain a conjugated C≡C bond starting from a terminal alkyne. Protegenin A is a derivative of octadecanoic acid that contains an ene-tetrayne moiety. It was discovered in Pseudomonas protegens Cab57 and exhibits strong antioomycete and moderate antifungal activity. By introducing cayG, a cytochrome P450 gene from Burkholderia caryophylli, into P. protegens Cab57, protegenin A was converted into more complex polyynes, caryoynencins A-E. A purification method that minimized the degradation and isomerization of caryoynencins was established. For the first time, as far as we know, the 1H and 13C{1H} NMR signals of caryoynencins were completely assigned by analyzing the NMR data of the isolated compounds and protegenin A enriched with [1-13C]- or [2-13C]-acetate. Through the structural analysis of caryoynencins D/E and bioconversion experiments, we observed that CayG constructs the allyl alcohol moiety of caryoynencins A-C through sequential hydroxylation, dehydration, and hydroxylation. The recombinant strain exhibited a stronger antioomycete activity compared to the wild-type strain. This paper proposes a stable purification and structural determination method for various bacterial polyynes, and P. protegens Cab57 holds promise as an engineering host for the production of biologically active polyynes.


Assuntos
Bactérias , Poli-Inos , Poli-Inos/metabolismo , Antifúngicos/metabolismo , Pseudomonas/genética , Pseudomonas/química , Pseudomonas/metabolismo
13.
Chem Biodivers ; 20(3): e202200196, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36879423

RESUMO

The chemical investigation of the methanol extract of the whole plant of Gymnanthemum theophrastifolium (Schweinf. ex Oliv. & Hiern) H.Rob. (Asteraceae) led to the isolation of a new elemane-type sesquiterpene (1), a new acetonide derived polyacetylene (2) and a naturally occurring compound (3) from the plant kingdom along with sixteen known compounds (4-19). Their structures were elucidated by extensive NMR and MS analysis. This is the first report on the chemical constituents of G. theophrastifolium. Furthermore, compounds 12, 13, and 14 are reported for the first time from the family Asteraceae, while compound 9 is reported for the first time from the genus Gymnanthemum. Thus, the present results provide valuable insights to the chemophenetic knowledge of G. theophrastifolium, which is also discussed in this work.


Assuntos
Asteraceae , Sesquiterpenos , Polímero Poliacetilênico , Sesquiterpenos Monocíclicos , Estrutura Molecular , Asteraceae/química , Sesquiterpenos/química , Poli-Inos/farmacologia , Extratos Vegetais/química
14.
Molecules ; 28(4)2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36838824

RESUMO

(E)-7-Phenyl-2-hepten-4,6-diyn-1-ol (1) and (Z)-7-Phenyl-2-hepten-4,6-diyn-1-ol (2) are isomeric natural polyacetylenes isolated from the Chinese medicinal plant Bidens pilosa L. This study first revealed the excellent anti-metastasis potential of these two polyacetylenes on human gastric cancer HGC-27 cells and the distinctive molecular mechanisms underlying their activities. Polyacetylenes 1 and 2 significantly inhibited the migration, invasion, and adhesion of HGC-27 cells at their non-toxic concentrations in a dose-dependent manner. The results of a further mechanism investigation showed that polyacetylene 1 inhibited the expressions of Vimentin, Snail, ß-catenin, GSK3ß, MST1, YAP, YAP/TAZ, and their phosphorylation, and upregulated the expression of E-cadherin and p-LATS1. In addition, the expressions of various downstream metastasis-related proteins, such as MMP2/7/9/14, c-Myc, ICAM-1, VCAM-1, MAPK, p-MAPK, Sox2, Cox2, and Cyr61, were also suppressed in a dose-dependent manner. These findings suggested that polyacetylene 1 exhibited its anti-metastasis activities on HGC-27 cells through the reversal of the EMT process and the suppression of the Wnt/ß-catenin and Hippo/YAP signaling pathways.


Assuntos
Bidens , Neoplasias Gástricas , Humanos , beta Catenina/metabolismo , Polímero Poliacetilênico , Via de Sinalização Hippo , Poli-Inos , Via de Sinalização Wnt
15.
Molecules ; 28(8)2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-37110760

RESUMO

Diverse secondary metabolites are biosynthesized by plants via various enzymatic cascades. These have the capacity to interact with various human receptors, particularly enzymes implicated in the etiology of several diseases. The n-hexane fraction of the whole plant extract of the wild edible plant, Launaea capitata (Spreng.) Dandy was purified by column chromatography. Five polyacetylene derivatives were identified, including (3S,8E)-deca-8-en-4,6-diyne-1,3-diol (1A), (3S)-deca-4,6,8-triyne-1,3-diol (1B), (3S)-(6E,12E)-tetradecadiene-8,10-diyne-1,3-diol (2), bidensyneoside (3), and (3S)-(6E,12E)-tetradecadiene-8,10-diyne-1-ol-3-O-ß-D-glucopyranoside (4). These compounds were investigated for their in vitro inhibitory activity against enzymes involved in neuroinflammatory disorders, including cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and butyrylcholinesterase (BchE) enzymes. All isolates recorded weak-moderate activities against COX-2. However, the polyacetylene glycoside (4) showed dual inhibition against BchE (IC50 14.77 ± 1.55 µM) and 5-LOX (IC50 34.59 ± 4.26 µM). Molecular docking experiments were conducted to explain these results, which showed that compound 4 exhibited greater binding affinity to 5-LOX (-8.132 kcal/mol) compared to the cocrystallized ligand (-6.218 kcal/mol). Similarly, 4 showed a good binding affinity to BchE (-7.305 kcal/mol), which was comparable to the cocrystallized ligand (-8.049 kcal/mol). Simultaneous docking was used to study the combinatorial affinity of the unresolved mixture 1A/1B to the active sites of the tested enzymes. Generally, the individual molecules showed lower docking scores against all the investigated targets compared to their combination, which was consistent with the in vitro results. This study demonstrated that the presence of a sugar moiety (in 3 and 4) resulted in dual inhibition of 5-LOX and BchE enzymes compared to their free polyacetylenes analogs. Thus, polyacetylene glycosides could be suggested as potential leads for developing new inhibitors against the enzymes involved in neuroinflammation.


Assuntos
Asteraceae , Butirilcolinesterase , Humanos , Ciclo-Oxigenase 2/metabolismo , Polímero Poliacetilênico/farmacologia , Simulação de Acoplamento Molecular , Ligantes , Inibidores da Colinesterase/farmacologia , Asteraceae/metabolismo , Poli-Inos/química , Glicosídeos/química , Di-Inos , Inibidores de Lipoxigenase/farmacologia , Inibidores de Lipoxigenase/química
16.
Chembiochem ; 23(21): e202200430, 2022 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-36107027

RESUMO

Various bacterial species are capable of producing highly modified fatty acid derivatives with conjugated triple bonds, which play important ecological roles as antifungals and toxins in mutualistic and pathogenic interactions. Furthermore, the terminal polyyne moiety is of interest as pharmacophore and as tag in bioorthogonal chemistry and live imaging. To gain insight into the assembly of these highly reactive natural products, we investigated tetrayne (caryoynencin and protegencin) biosynthesis genes (cay and pgn) from Trinickia caryophylli and Pseudomonas protegens. Pathway dissection and reconstitution in the heterologous host Burkholderia graminis revealed the genes minimally required for polyyne formation. Mutational analyses and biochemical assays demonstrated that polyyne biosynthesis is thiotemplated, involving a fatty acyl-AMP ligase, a designated acyl carrier protein, and a thioesterase. Heterologous expression of point-mutated desaturase genes showed that three desaturases work synergistically to introduce four triple bonds. These findings point to an intricate desaturase complex and provide important information for future bioengineering experiments.


Assuntos
Bactérias , Ácidos Graxos , Ácidos Graxos/química , Bactérias/metabolismo , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/química , Ácidos Graxos Dessaturases/metabolismo , Poli-Inos
17.
Chem Rec ; 22(1): e202100176, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34665514

RESUMO

Polyacetylene glycosides (PAGs) constitute a relatively small class of secondary metabolites characterized by the presence of a sugar unit anomerically connected to a polyacetylene. These compounds are found in fungi, seaweed, and more often in plants. PAGs exhibit a wide range of biological and pharmacological activities and, as a result, the literature of these compounds has grown exponentially in recent years.


Assuntos
Glicosídeos , Poli-Inos , Fungos , Plantas , Polímero Poliacetilênico
18.
Macromol Rapid Commun ; 43(11): e2200111, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35429085

RESUMO

Polymer-based circularly polarized luminescent (CPL) materials have attracted ever-increasing interest. However, to construct CPL materials from achiral monomers is still a big challenge. Here, a series of chiral helical substituted polyacetylenes are prepared by helix-sense-selective polymerization (HSSP) of achiral acetylenic monomers (achiral monomer + fluorescent monomer). HSSPs are accomplished in a bi-solvent mixture consisting of chloroform and chiral α-pinene (chiral component). Chirality transfers from the chiral component to the helical copolymers during polymerization, thereby endowing the copolymers with helical chirality. The resulting copolymers are then fabricated into blend films which exhibit intense optical activity and CPL. The monomer ratio and the physical state of the copolymers have significant impacts on their chiroptical and CPL properties. The maximum luminescence dissymmetry factor of the blend films can be up to 1.3 × 10-2 . The universality of the established strategy for exploring polymer-based CPL materials is demonstrated by using different achiral fluorescent monomers. The present work opens a novel alternative for developing CPL-active polymeric materials starting from achiral monomers.


Assuntos
Luminescência , Poli-Inos , Polímero Poliacetilênico , Polimerização , Polímeros
19.
J Nat Prod ; 85(4): 866-877, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35324175

RESUMO

Twenty-two sesquiterpenoids (1-22) and 11 polyacetylenes (23-33) were obtained from the rhizomes of Atractylodes lancea. Among them, 11 compounds (1-5, 11, 12, 23, 24, 30, and 31) are new. The scaffolds represented by the isolates of sesquiterpenoids were found to be varied and included two rare rearranged spirovetivane sesquiterpenoids with a spiro [4,4] skeleton, eight spirovetivanes, three guaianes, eight eudesmanes, and one eremophilane. Their planar structures and relative configurations were elucidated by UV, IR, 1D and 2D NMR, and HRESIMS data analysis. The absolute configurations of the new sesquiterpenoids were determined using X-ray diffraction analysis and by comparison of the calculated and experimental electronic circular dichroism and optical rotation data, as well as chemical transformations. All the isolated compounds (1-33) were evaluated for their activity against RANKL-induced osteoclastogenesis in bone marrow macrophages. Two polyacetylene-type compounds, 25 and 32, showed potent activity with IC50 values of 1.3 and 0.64 µM, respectively. Rearranged spirovetivane sesquiterpenoids with a spiro [4,4] skeleton are reported herein from the genus Atractylodes for the first time. Polyacetylenes were demonstrated as the main active constituents of A. lancea with osteoclastogenesis inhibitory activity.


Assuntos
Atractylodes , Sesquiterpenos , Atractylodes/química , Estrutura Molecular , Osteogênese , Poli-Inos/química , Poli-Inos/farmacologia , Rizoma/química , Sesquiterpenos/química
20.
Chem Biodivers ; 19(11): e202200557, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36201258

RESUMO

In this study, the anticholinesterase effects of the extracts and isolated compounds from the roots of endemic Prangos uechtritzii Boiss & Hausskn (Apiaceae) are reported. A novel polyacetylenic compound; (+)-8-O-methyloplopantriol A along with two known polyacetylenes; (-)-panaxynol, (+)-falcarindiol and fifteen known coumarin derivatives; umbelliferone, 6-formylumbelliferone, suberosin, 7-demethylsuberosin, (+)-ulopterol, tamarin, psoralen, imperatorin, (+)-oxypeucedanin, (+)-oxypeucedanin hydrate, (+)-oxypeucedanin methanolate, (+)-marmesin, (-)-prantschimgin, (+)-decursinol, and (-)-adicardin were isolated from the hexane (Pu-HE), chloroform (Pu-CE), and methanol (Pu-ME) extracts of P. uechtritzii roots. (-)-Panaxynol, (+)-falcarindiol, 6-formylumbelliferone, (+)-decursinol, and (-)-adicardin were obtained from the genus Prangos for the first time. (+)-8-O-Methyloplopantriol A inhibited both AChE (IC50 =194.5±5.8 µM) and BChE (IC50 =51.9±2.96 µM) enzymes. (+)-Falcarindiol, 6-formylumbelliferone, 7-demethylsuberosin, tamarin, and imperatorin also exhibited BChE-specific inhibitory activities (IC50 =27.88-93.86 µM). (+)-Falcarindiol (IC50 =27.88±0.91 µM) and imperatorin (IC50 =30.89±1.40 µM) as the most active components could be led compounds to develop new BChE inhibitors with further research against Alzheimer's disease.


Assuntos
Apiaceae , Inibidores da Colinesterase , Apiaceae/química , Inibidores da Colinesterase/farmacologia , Cumarínicos/química , Cumarínicos/farmacologia , Extratos Vegetais/farmacologia , Poli-Inos/química , Poli-Inos/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA