RESUMEN
The diterpene cafestol represents the most potent cholesterol-elevating compound known in the human diet, being responsible for more than 80% of the effect of coffee on serum lipids, with a mechanism still not fully clarified. In the present study, the interaction of cafestol and 16-O-methylcafestol with the stabilized ligand-binding domain (LBD) of the Farnesoid X Receptor was evaluated by fluorescence and circular dichroism. Fluorescence quenching was observed with both cafestol and 16-O-methylcafestol due to an interaction occurring in the close environment of the tryptophan W454 residue of the protein, as confirmed by docking and molecular dynamics. A conformational change of the protein was also observed by circular dichroism, particularly for cafestol. These results provide evidence at the molecular level of the interactions of FXR with the coffee diterpenes, confirming that cafestol can act as an agonist of FXR, causing an enhancement of the cholesterol level in blood serum.
Asunto(s)
Colesterol , Café , Diterpenos , Receptores Citoplasmáticos y Nucleares , Diterpenos/farmacología , Diterpenos/química , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores Citoplasmáticos y Nucleares/agonistas , Colesterol/metabolismo , Humanos , Café/química , Simulación del Acoplamiento Molecular , Unión Proteica , Simulación de Dinámica Molecular , Dicroismo CircularRESUMEN
Green coffee beans are particularly rich in chlorogenic acids (CGAs), and their identification and quantification are usually performed by HPLC, coupled with mass spectrometry (LC-MS). Although there are a few examples of molecularly imprinted polymers (MIPs) for chlorogenic acid (5-CQA) recognition present in the literature, none of them are based on optical fluorescence, which is very interesting given its great sensitivity. In the present manuscript, fluorescent polymeric imprinted nanoparticles were synthetized following the non-covalent approach using hydrogenated 5-O-caffeoylquinic acid (H-5-CQA) as the template. The capability of the polymer to bind 5-CQA was evaluated by HPLC and fluorescence. A real sample of coffee extract was also analyzed to verify the selectivity of the polymer. Polymer fMIP01, containing 4-vinylpyridine and a naphtalimide derivative as monomers, showed a good response to the fluorescence quenching in the range 39 µM-80 mM. In the real sample, fMIP01 was able to selectively bind 5-CQA, while caffeine was not recognized. To demonstrate this, there is a promising system that can be exploited in the design of an optical sensor for 5-CQA detection. Polymer fMIP01 was immobilized by physical entrapment on a functionalized glass surface, showing a quenching of fluorescence with an increase of the CGA concentration between 156 µM and 40 mM.
Asunto(s)
Ácido Clorogénico , Nanopartículas , Cafeína , Cromatografía Líquida de Alta Presión , Polímeros/químicaRESUMEN
The cultivar Bianchera is an autochthonous variety from the eastern part of northern Italy, but it is also cultivated in the Slovenian and Croatian peninsula of Istria where it is named Belica (Slovenia) and Bjelica (Croatia). The properties of oleocanthal, a natural anti-inflammatory ibuprofen-like compound found in commercial monocultivar extra virgin olive oils, were determined by means of both quantitative 1H NMR (qNMR) and HPLC analyses, where qNMR was identified as a rapid and reliable method for determining the oleocanthal content. The total phenolic content (TPC) was determined by means of the Folin-Ciocalteau method and the major phenols present in the olive oils were also quantified by means of HPLC analyses. All these analyses confirmed that the cultivar Bianchera was very rich in polyphenols and satisfied the health claim provided by the EU Commission Regulation on the polyphenols content of olive oils and their beneficial effects on human health.
Asunto(s)
Aldehídos/análisis , Cromatografía Líquida de Alta Presión/métodos , Monoterpenos Ciclopentánicos/análisis , Espectroscopía de Resonancia Magnética/métodos , Olea/química , Aceite de Oliva/análisis , Fenoles/análisis , Extractos Vegetales/química , Polifenoles/análisis , Humanos , Hojas de la Planta/químicaRESUMEN
The main coffee diterpenes cafestol, kahweol, and 16-O-methylcafestol, present in the bean lipid fraction, are mostly esterified with fatty acids. They are believed to induce dyslipidaemia and hypercholesterolemia when taken with certain types of coffee brews. The study of their binding to serum albumins could help explain their interactions with biologically active xenobiotics. We investigated the interactions occurring between cafestol and 16-O-methylcafestol palmitates with Bovine Serum Albumin (BSA), Human Serum Albumin (HSA), and Fatty Free Human Serum Albumin (ffHSA) by means of circular dichroism and fluorimetry. Circular Dichroism (CD) revealed a slight change (up to 3%) in the secondary structure of fatty-free human albumin in the presence of the diterpene esters, suggesting that the aliphatic chain of the palmitate partly occupies one of the fatty acid sites of the protein. A warfarin displacement experiment was performed to identify the binding site, which is probably close but not coincident with Sudlow site I, as the affinity for warfarin is enhanced. Fluorescence quenching titrations revealed a complex behaviour, with Stern-Volmer constants in the order of 103-104 Lmol-1. A model of the HSA-warfarin-cafestol palmitate complex was obtained by docking, and the most favourable solution was found with the terpene palmitate chain inside the FA4 fatty acid site and the cafestol moiety fronting warfarin at the interface with site I.
Asunto(s)
Diterpenos/metabolismo , Ácidos Grasos no Esterificados/metabolismo , Albúmina Sérica Bovina/metabolismo , Albúmina Sérica Humana/metabolismo , Animales , Sitios de Unión , Bovinos , Café , Diterpenos/química , Ácidos Grasos no Esterificados/química , Humanos , Modelos Moleculares , Unión Proteica , Conformación Proteica , Albúmina Sérica Bovina/química , Albúmina Sérica Humana/químicaRESUMEN
RNA isolated from fixed and paraffin-embedded tissues is widely used in biomedical research and molecular pathology for diagnosis. In the present study, we have set-up a method based on high performance liquid chromatography (HPLC) to investigate the effects of different fixatives on RNA. By the application of the presented method, which is based on the Nuclease S1 enzymatic digestion of RNA extracts followed by a HPLC analysis, it is possible to quantify the unmodified nucleotide monophosphates (NMPs) in the mixture and recognize their hydroxymethyl derivatives as well as other un-canonical RNA moieties. The results obtained from a set of mouse livers fixed/embedded with different protocols as well from a set of clinical samples aged 0 to 30 years-old show that alcohol-based fixatives do not induce chemical modification of the nucleic acid under ISO standard recommendations and confirm that pre-analytical conditions play a major role in RNA preservation.
Asunto(s)
Cromatografía Liquida/métodos , ARN/química , Adhesión del Tejido/métodos , Fijación del Tejido/métodos , Animales , Fijadores/efectos adversos , Hígado/química , Ratones , ARN/análisis , Adhesión del Tejido/normas , Fijación del Tejido/normasRESUMEN
The synthesis of five hydroxycinnamoyl amides (HCAs) was accomplished and their identification and quantification in the green coffee bean samples of Coffea arabica, Coffea canephora, and Coffea liberica was performed. The HCAs p-coumaroyl-N-tyrosine 1b, caffeoyl-N-phenylalanine 2b, caffeoyl-N-tyrosine 3b, and p-coumaroyl-N-tryptophan 4b were characteristic of the C. canephora species while caffeoyl-N-tryptophan 5b was present in both C. canephora and C. arabica, but with higher content in C. canephora. The HCAs presence was also analyzed in C. liberica for the first time and none of the targeted compounds was found, indicating that this species is very similar to C. arabica species. Between C. canephora samples from various origins, significant differences were observed regarding the presence of all the HCAs, with C. canephora from Tanzania containing all five derivatives.
Asunto(s)
Aminoácidos/química , Coffea/química , Ácidos Cumáricos/química , Amidas/química , Dicroismo Circular , Dimerización , Espectrometría de Masas , Estereoisomerismo , Factores de TiempoRESUMEN
Chlorogenic acids are secondary metabolites in diverse plants. Some chlorogenic acids extracted from traditional medicinal plants are known for their healing properties, e.g., against viral infections. Also, green coffee beans are a rich source of chlorogenic acids, with 5-O-caffeoylquinic acid being the most abundant chlorogenic acid in coffee. We previously reported the synthesis of the regioisomers of lactones, bearing different substituents on the quinidic core. Here, 3,4-O-dicaffeoyl-1,5-γ-quinide and three dimethoxycinnamoyl-γ-quinides were investigated for in vitro antiviral activities against a panel of 14 human viruses. Whereas the dimethoxycinnamoyl-γ-quinides did not show any antiviral potency in cytopathogenic effect reduction assays, 3,4-O-dicaffeoyl-1,5-γ-quinide exerted mild antiviral activity against herpes simplex viruses, adenovirus, and influenza virus. Interestingly, when the compounds were evaluated against respiratory syncytial virus, a potent antiviral effect of 3,4-O-dicaffeoyl-1,5-γ-quinide was observed against both subtypes of respiratory syncytial virus, with EC50 values in the submicromolar range. Time-of-addition experiments revealed that this compound acts on an intracellular post-entry replication step. Our data show that 3,4-O-dicaffeoyl-1,5-γ-quinide is a relevant candidate for lead optimization and further mechanistic studies, and warrants clinical development as a potential anti-respiratory syncytial virus drug.
Asunto(s)
Antivirales/farmacología , Ácido Clorogénico/uso terapéutico , Café/química , Extractos Vegetales/uso terapéutico , Ácido Quínico/análogos & derivados , Virus/efectos de los fármacos , Animales , Chlorocebus aethiops , Células HEK293 , Células HeLa , Humanos , Orthomyxoviridae/efectos de los fármacos , Ácido Quínico/uso terapéutico , Virus Sincitiales Respiratorios/efectos de los fármacos , Sistema Respiratorio/virología , Células VeroRESUMEN
Both enantiomers of three biologically relevant paraconic acids-MB-3, methylenolactocin, and C75-were obtained with enantioselectivities up to 99% by kinetic enzymatic resolutions. Good enantiomeric excesses were obtained for MB-3 and methylenolactocin, using α-chymotrypsin and aminoacylase as enantiocomplementary enzymes, while C75 was resolved with aminoacylase. They all were evaluated for their antiproliferative, antibacterial, and antifungal activities, showing weak effects and practically no difference between enantiomers in each case. At high concentrations (16-64 µg/mL), (-)- C75 acted as an antimicrobial agent against Gram-positive bacteria.
Asunto(s)
4-Butirolactona/análogos & derivados , Antiinfecciosos/farmacología , Antineoplásicos/farmacología , 4-Butirolactona/química , 4-Butirolactona/farmacología , Amidohidrolasas/metabolismo , Quimotripsina/metabolismo , Humanos , Células MCF-7 , EstereoisomerismoRESUMEN
Enantiomerically enriched isoparaconic acid derivatives were obtained by kinetic enzymatic resolution. To explain the solvent dependence observed for their optical rotatory power a computational investigation of their chiroptical properties was performed.
Asunto(s)
4-Butirolactona/análogos & derivados , Hidrolasas/metabolismo , 4-Butirolactona/síntesis química , 4-Butirolactona/química , Animales , Técnicas de Química Sintética , Cinética , Teoría Cuántica , EstereoisomerismoRESUMEN
A computational investigation of the specific optical rotation and of the electronic circular dichroism spectra of two chiral 1,4-dihydropyridazines was performed and compared with existing experimental data to verify a previous assignment of their absolute configuration based on a well-accepted mechanism of catalysis of the organocatalyst used in their synthesis. Both the optical rotation and circular dichroism calculations indicate that the absolute configuration is opposite to the one assigned on the basis of the mechanism originally assumed. An alternative reaction mechanism is therefore suggested.
Asunto(s)
Compuestos Orgánicos/química , Piridazinas/síntesis química , Catálisis , Estructura Molecular , Piridazinas/química , Teoría Cuántica , EstereoisomerismoRESUMEN
(R)-(+) and (S)-(-)-1-phenylethylamine have been shown to promote highly diastereoselective and complementary enantioselective formal [3 + 2]carbocyclization reactions between 2,3-butanedione and conjugated nitroalkenes with formation of enantiomerically rich 2-hydroxy-3-nitrocyclopentanone derivatives. The reactions were carried out both in solvent and under solvent-free conditions. The absolute configurations of the products were assigned by X-ray and circular dichroism spectra analyses.
RESUMEN
The distinctive nucleus of kainoid amino acids, (2S,3R)-(+)-2-carboxypyrrolidine-3-acetic acid 6, was synthesized by a chemoenzymatic process, exploiting the diastereomeric cis/trans methyl pyroglutamate derivatives 10a-c/11a-c as key intermediates. These mixtures, when subjected to a kinetic resolution mediated by α-chymotrypsin, reacted diastereo-, regio-, and enantioselectively to give the trans derivatives (+)-10a-c possessing the correct (2S,3R) configuration. Subsequently, the desired product (2S,3R)-(+)-6 could be obtained after well-established transformations.
Asunto(s)
Acetatos/síntesis química , Aminoácidos/química , Pirrolidinas/síntesis química , Quimotripsina/química , Ácido Kaínico/química , Pirrolidinas/química , EstereoisomerismoRESUMEN
Diterpenes represent a wider class of isoprenoids, with more than 18,000 isolated compounds, and are present in plants, fungi, bacteria, and animals in both terrestrial and marine environments. Here, we report on the fully characterised structures of 251 new diterpenes, isolated from higher plants and published from 2017, which are shown to have antitumoral activity. An overview on the most active compounds, showing IC50 < 20 µM, is provided for diterpenes of different classes. The most active compounds were extracted from 29 different plant families; particularly, Euphorbiaceae (69 compounds) and Lamiaceae (54 compounds) were the richest sources of active compounds. A better activity than the positive control was obtained with 33 compounds against the A549 cell line, 28 compounds against the MCF-7 cell line, 9 compounds against the HepG2 cell line, 8 compounds against the Hep3B cell line, 19 compounds against the SMMC-7721 cell line, 9 compounds against the HL-60 cell line, 24 compounds against the SW480 cell line, and 19 compounds against HeLa.
RESUMEN
Gastrointestinal nematodes are one of the major threats in small ruminant breeding. Their control is difficult due to the development of anthelmintic resistance, and the search for new molecules endowed with anthelmintic activity (AH) is considered a priority. In this context, we evaluated the in vitro AH activity of two commercial sea buckthorn (Hippophae rhamnoides) berry juices, namely SBT and SBF. The in vitro evaluation was based on the egg-hatch test and larval exsheathment assay at different concentrations. Data were statistically analysed, and the EC50 was calculated. Chemical analyses were performed to evaluate the total polyphenol content of the juices and chemical profile of the most represented compounds. The role of the polyphenolic fraction in the anthelmintic activity of the juices was also assessed. At the highest concentrations, the activity of SBT was high in both tests and comparable to that observed in the thiabendazole-treated positive controls, while SBF showed a lower efficacy. Glycosylated isorhamnetin and quercetin were the most represented polyphenolic compounds in both juices. In conclusion, both H. rhamnoides berry juices tested in this study showed interesting anthelmintic properties in vitro.
RESUMEN
Cinnamic acids are an important class of phenolic compounds, which have many beneficial effects on human health but are also interesting synthetic intermediates thanks to the presence of several reactive sites. While studying the reactivity of cinnamic acids with diazonium salts from aromatic amines, an unexpected reactivity has been discovered, leading to the formation of 1,2-diaza-1,3-dienes instead of traditional diazo-coupling products. The new compounds have been fully characterized by mono and bidimensional NMR spectroscopy and mass spectrometry. Preliminary studies on the biological activity of the compounds have been carried out testing both their antibacterial and antitumor activity, leading to promising results.
RESUMEN
Phenolic compounds are secondary metabolites frequently found in plants that exhibit many different effects on human health. Because of the relevant bioactivity, their identification and quantification in agro-food matrices as well as in biological samples are a fundamental issue in the field of quality control of food and food supplements, and clinical analysis. In this review, a critical selection of sensors and biosensors for rapid and selective detection of phenolic compounds is discussed. Sensors based on electrochemistry, photoelectrochemistry, fluorescence, and colorimetry are discussed including devices with or without specific recognition elements, such as biomolecules, enzymes and molecularly imprinted materials. Systems that have been tested on real matrices are prevalently considered but also techniques that show potential development in the field.
Asunto(s)
Técnicas Biosensibles , Fenoles/análisis , Plantas/química , Técnicas Electroquímicas , Electroquímica , Impresión MolecularRESUMEN
The activation of signals in fluorescent nanosensors upon interaction with their targets is highly desirable. To this aim, several molecularly imprinted nanogels have been synthetized for the recognition of tyrosol, hydroxytyrosol and oleuropein in aqueous extracts using the non-covalent approach. Two of them contain fluorescein derivatives as co-monomers, and their fluorescence emission is switched on upon binding of the target phenols. The selection of functional monomers was previously done by analyzing the interactions by nuclear magnetic resonance (NMR) in deuterated dimethylsulfoxide (DMSO-d6) of the monomers with tyrosol and hydroxytyrosol. Polymers were synthetized under high dilution conditions to obtain micro- and nano-particles, as verified by transmission electron microscopy (TEM). 1,4-Divinylbenzene (DVB) was used in the fluorescent polymers in order to enhance the interactions with the aromatic ring of the templates tyrosol and hydroxytyrosol by π-π stacking. The results were fully satisfactory as to rebinding: DVB-crosslinked molecularly imprinted polymers (MIPs) gave over 50 nmol/mg rebinding. The sensitivity of the fluorescent MIPs was excellent, with LODs in the pM range. The sensing polymers were tested on real olive leaves extracts, with very good performance and negligible matrix effects.
RESUMEN
Fluorescent, imprinted nanosized polymers for the detection of irinotecan have been synthesised using a napthalimide polymerisable derivative (2-allyl-6-[2-(aminoethyl)-amino] napthalimide) as functional monomer. The imprinted polymers contain ethylene glycol dimethacrylate (EGDMA) as a cross-linker and were prepared by high dilution radical polymerisation in dimethylsulphoxide (DMSO). The material was able to rebind irinotecan up to 18 nmol/mg with good specificity. Fluorescence emission at 525 nm (excitation at 448 nm) was quenched by increasing concentrations of irinotecan via a static mechanism and also in analytically useful environments as mixtures of human plasma and organic solvents. This allowed the direct detection of irinotecan (in the 10 nM-30 µM range) in human plasma treated with acetonitrile; the limit of detection (LOD) was 9.4 nM, with within-run variability of 10% and day-to-day variability of 13%.
RESUMEN
Quantitative analyses of mono-p-coumaroylquinic acids (pCoQAs) and total chlorogenic acids (CGAs) in green coffee commercial lots of C. arabica, C. canephora and C. liberica from different geographical origins and eight wild Coffea species were carried out. Among the commercial lots, pCoQAs average content of C. arabica (0.67â¯mg/g) is higher than that of C. canephora (0.40â¯mg/g) being C. liberica intermediate (0.58â¯mg/g). As far as the analyzed wild Coffea species is concerned, C. pseudozanguebariae is characterized by the lower pCoQAs content (0.12â¯mg/g) whereas C. sessiliflora is by far the richest source of pCoQAs (2.18â¯mg/g). Effect of the roasting process on the mono-p-coumaroylquinic acids profile was evaluated for the economically exploited species C. arabica and C. canephora. For the first time distribution of mono-p-coumaroylquinic acid isomers in wild coffee species by fast and accurate UHPLC-DAD analyses using authentic standards previously synthetized, is reported.
Asunto(s)
Ácido Clorogénico/análisis , Coffea/química , Ácido Quínico/análisis , Ácido Clorogénico/análogos & derivados , Cromatografía Líquida de Alta Presión/métodos , Café/química , Manipulación de Alimentos , Isomerismo , Ácido Quínico/análogos & derivados , Ácido Quínico/química , Semillas/químicaRESUMEN
Identification of both hydroxycinnamic and chlorogenic acids present in aqueous extracts of walnut leaves (Juglans regia L.) were carried out by using, for the first time, standard compounds not commercially available for qualitative identification. In particular, in addition to caffeic, ferulic, p-coumaric and sinapic acids, cis and trans mono-caffeoylquinic, dicaffeoylquinic, mono-feruloylquinic and cis and trans mono-p-coumaroylquinic acid isomers were detected and quantified by Ultra High Pressure Liquid Chromatography and the seasonal variations of these secondary metabolites were investigated.