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1.
Nutrients ; 15(9)2023 Apr 28.
Article in English | MEDLINE | ID: mdl-37432298

ABSTRACT

In our previous studies, Prunus spinosa fruit (PSF) ethanol extract was showed to exert antioxidant, antimicrobial, anti-inflammatory and wound healing activities. In the present study, an integrated bioinformatics analysis combined with experimental validation was carried out to investigate the biological mechanism(s) that are responsible for the reported PSF beneficial effects as an antioxidant during a pro-inflammatory TLR4 insult. Bioinformatics analysis using miRNet 2.0 was carried out to address which biological process(es) the extract could be involved in. In addition, Chemprop was employed to identify the key targets of nuclear receptor (NR) signaling and stress response (SR) pathways potentially modulated. The miRNet analysis suggested that the PSF extract mostly activates the biological process of cellular senescence. The Chemprop analysis predicted three possible targets for nine phytochemicals found in the extract: (i) ARE signaling, (ii) mitochondrial membrane potential (MMP) and (iii) p53 SR pathways. The PSF extract antioxidant effect was also experimentally validated in vitro using the human monocyte U937 cell line. Our findings showed that Nrf2 is modulated by the extract with a consequent reduction of the oxidative stress level. This was confirmed by a strong decrease in the amount of reactive oxygen species (ROS) observed in the PSF-treated cells subjected to lipopolysaccharide (LPS) (6 h treatment, 1 µg/mL). No visible effects were observed on p53 and MMP modulation.


Subject(s)
Prunus , Signal Transduction , Prunus/chemistry , Fruit/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Computational Biology , Humans , U937 Cells , Signal Transduction/drug effects , Antioxidants/pharmacology
2.
Food Chem ; 428: 136680, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-37418880

ABSTRACT

Quercetin-loaded nano-liposomes were prepared by high-pressure homogenization (HPH) at different pressures (up to 150 MPa) and number of passes (up to 3) to define the best processing conditions allowing the lowest particle size and the highest encapsulation efficiency (EE). The process at 150 MPa for 1 pass was the best, producing quercetin-loaded liposomes with the lowest particle size and 42% EE. Advanced techniques (multi-detector asymmetrical-flow field flow fractionation and analytical ultracentrifugation combined with transmission electron microscopy) were further used for the characterization of the liposomes which were oblong in shape (ca. 30 nm). Results highlight the need for several techniques to study nano-sized, polydisperse samples. The potential of quercetin-loaded liposomes against colon cancer cells was demonstrated. Results prove that HPH is an efficient and sustainable method for liposome preparation and highlight the remarkable role of process optimisation as well as the powerfulness of advanced methodologies for the characterisation of nano-structures.


Subject(s)
Liposomes , Nanoparticles , Liposomes/chemistry , Quercetin/chemistry , Microscopy, Electron, Transmission , Particle Size , Nanoparticles/chemistry
3.
FEBS J ; 290(7): 1740-1764, 2023 04.
Article in English | MEDLINE | ID: mdl-36310106

ABSTRACT

The nuclear RNA surveillance mechanism is essential for cancer cell survival and is ensured by the RNA nuclear exosome including some co-factors, such as the RNA helicase MTR4. Recent studies suggest an involvement of DNA repair proteins such as apurinic/apyrimidinic (AP) endodeoxyribonuclease 1 (APE1), a major endodeoxyribonuclease of Base Excision Repair (BER), in RNA metabolism and RNA decay of oxidized and abasic RNA. Cisplatin (CDDP) and 5-fluorouracil (5-FU) are commonly used for the treatment of solid tumours. Whether APE1 is involved in the elimination of CDDP- or 5-FU-damaged RNA is unknown, as is its possible interaction with the nuclear exosome complex. Here, by using different human cancer cell models, we demonstrated that: (a) APE1 is involved in the elimination of damaged-RNA, upon CDDP- and 5-FU-treatments, in a MTR4-independent manner; (b) the interaction between APE1 and MTR4 is stimulated by CDDP- and 5-FU-treatments through lysine residues in the APE1 N-terminal region and is, in part, mediated by nucleic acids and (c) APE1- and MTR4-depletion lead to the generation of R-loop formation causing the activation of the DNA damage response (DDR) pathway through the ATM-p53-p21 axis. Our data demonstrate a role of MTR4 in DDR underpinning the function of APE1 in controlling the RNA quality upon genotoxic treatments with possible implications in chemoresistance.


Subject(s)
Exosomes , Nuclear Proteins , Humans , Cisplatin/pharmacology , DNA Damage , DNA Repair , Endodeoxyribonucleases/metabolism , Exosomes/metabolism , Fluorouracil/pharmacology , Nuclear Proteins/genetics , Protein Binding , RNA/genetics , RNA/metabolism
4.
Antioxidants (Basel) ; 11(5)2022 Apr 27.
Article in English | MEDLINE | ID: mdl-35624724

ABSTRACT

Cannabis sativa var. Kompolti, a variety routinely used for food production purposes, is characterized by a low concentration of psychoactive molecules, although containing many other biologically attractive metabolites in all parts of the plant, including the roots. In the present work, we evaluate the specific biological activities of the roots' extract from plants cultivated through aeroponics, an affordable and reliable method facilitating the isolation and processing of roots, with the advantage of being suitable for industrial scale-up. Furthermore, aeroponics results in an increased net accumulation of the most biologically attractive constituents (ß-sitosterol, friedelin and epi-friedelanol) found in the roots. The ethanolic extract of the aeroponic roots of C. sativa (APEX) and its separate components are studied to evaluate their anti-inflammatory (modulation of the expression level of specific markers upon LPS stimulation in U937 cells, such as IL-6, IL-8, TNF-α, IkB-α, iNOS, IRAK-1 and miR-146a) and antioxidant (in either acellular or cellular settings) activities. The APEX anti-inflammatory and antioxidant capacities are also functionally benchmarked using the wound-healing assay. On the whole, the data obtained show that APEX and its main components showed significant anti-inflammatory and antioxidant activities, which may render the exploitation of roots as a source of natural antioxidants and anti-inflammatory agents highly attractive, with the additional technical and economic advantages of aeroponics compared to soil cultivation.

5.
Molecules ; 26(16)2021 Aug 12.
Article in English | MEDLINE | ID: mdl-34443479

ABSTRACT

Cannabis sativa L. has been used for a long time to obtain food, fiber, and as a medicinal and psychoactive plant. Today, the nutraceutical potential of C.sativa is being increasingly reappraised; however, C. sativa roots remain poorly studied, despite citations in the scientific literature. In this direction, we identified and quantified the presence of valuable bioactives (namely, ß-sitosterol, stigmasterol, campesterol, friedelin, and epi-friedelanol) in the root extracts of C. sativa, a finding which might pave the way to the exploitation of the therapeutic potential of all parts of the C. sativa plant. To facilitate root harvesting and processing, aeroponic (AP) and aeroponic-elicited cultures (AEP) were established and compared to soil-cultivated plants (SP). Interestingly, considerably increased plant growth-particularly of the roots-and a significant increase (up to 20-fold in the case of ß-sitosterol) in the total content of the aforementioned roots' bioactive molecules were observed in AP and AEP. In conclusion, aeroponics, an easy, standardized, contaminant-free cultivation technique, facilitates the harvesting/processing of roots along with a greater production of their secondary bioactive metabolites, which could be utilized in the formulation of health-promoting and health-care products.


Subject(s)
Cannabis/chemistry , Cannabis/growth & development , Hydroponics , Cholesterol/analogs & derivatives , Cholesterol/analysis , Oleanolic Acid/analogs & derivatives , Oleanolic Acid/analysis , Phytosterols/analysis , Plant Extracts/chemistry , Plant Roots/chemistry , Plant Roots/growth & development , Sitosterols/analysis , Stigmasterol/analysis , Triterpenes/analysis
6.
Int J Food Sci Nutr ; 72(2): 174-183, 2021 Mar.
Article in English | MEDLINE | ID: mdl-32597255

ABSTRACT

Conventional (CB) and apple-pomace-reformulated (RB) biscuits were administered to healthy rats. Although the areas under curve (AUC) of glucose concentration were comparable between samples, differences in the glycaemic profile of CB and RB were observed. RB caused an initial steeper increase in glycaemia but a shift in the glycaemic peak from 45 to 60 min, as compared to CB. When CB or RB was ingested with apple juice (AJ) no differences were observed as compared to their ingestion with a soft drink (SD) simulating AJ sugar content, indicating that reformulation, more than the presence of AJ, was crucial in affecting the glycaemic response. Consumer acceptability towards reformulation was assessed through conjoint analysis, by simulating labels reporting information on reformulation. Consumers preferred information generally referring to the health-promoting effect (i.e. "low sugar" and "high fibre" contents), despite directly relating to a specific disease (i.e. "suitable for diabetics" and "low glycaemic index").


Subject(s)
Blood Glucose/analysis , Food, Formulated , Fruit and Vegetable Juices , Malus , Animals , Consumer Behavior , Dietary Fiber , Glycemic Index , Humans , Male , Rats , Rats, Wistar
7.
Nanomaterials (Basel) ; 11(1)2020 Dec 25.
Article in English | MEDLINE | ID: mdl-33375632

ABSTRACT

Prunus spinosa fruits (PSF) contain different phenolic compounds showing antioxidant and anti-inflammatory activities. Innovative drug delivery systems such as biomimetic nanoparticles could improve the activity of PSF extract by promoting (i) the protection of payload into the lipidic bilayer, (ii) increased accumulation to the diseased tissue due to specific targeting properties, (iii) improved biocompatibility, (iv) low toxicity and increased bioavailability. Using membrane proteins extracted from human monocyte cell line THP-1 cells and a mixture of phospholipids, we formulated two types of PSF-extract-loaded biomimetic vesicles differing from each other for the presence of either 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DOPG). The biological activity of free extract (PSF), compared to both types of extract-loaded vesicles (PSF-DOPCs and PSF-DOPGs) and empty vesicles (DOPCs and DOPGs), was evaluated in vitro on HUVEC cells. PSF-DOPCs showed preferential incorporation of the extract. When enriched into the nanovesicles, the extract showed a significantly increased anti-inflammatory activity, and a pronounced wound-healing effect (with PSF-DOPCs more efficient than PSF-DOPG) compared to free PSF. This innovative drug delivery system, combining nutraceutical active ingredients into a biomimetic formulation, represents a possible adjuvant therapy for the treatment of wound healing. This nanoplatform could be useful for the encapsulation/enrichment of other nutraceutical products with short stability and low bioavailability.

8.
Food Funct ; 10(11): 7366-7377, 2019 Nov 01.
Article in English | MEDLINE | ID: mdl-31650989

ABSTRACT

Thermal (T) and ultrasound (US) pasteurization processes were applied to apple juice and the phenolic compounds (TPC) were quantified before and after in vitro digestion by HPLC-DAD-ESI-MSn, with their bioaccessibility ascertained. Digested samples were analysed for their inhibitory capacity against α-glucosidase. Since some of the compounds exhibit fluorescence, both steady state and time-resolved fluorescence methods were used to investigate the binding to a blood transport protein, human serum albumin (HSA). It was found that processing induced an increase in the TPC content, which was more pronounced when US was applied. In contrast, digestion reduced the TPC content, evening out the overall effect. Still T and US pasteurized juices exhibited a higher quantity of TPC upon digestion as compared to the raw sample. No correlation was found between the TPC content and α-glucosidase inhibition, as the T and US pasteurized juices showed the highest and lowest inhibitory capacities against the enzyme, respectively. This is indicative that other compounds, such as those formed upon thermal treatment, may be involved in the antidiabetic effect of apple juice. The fluorescence study showed that binding occurred to HSA, at slightly different rates for different species present in the US treated extract. Considering energy consumption, US pasteurization is the most power consuming treatment despite its shorter duration. Overall, no univocal indication on the best pasteurization process can be gathered. Thus, it is necessary to define the desired target in order to drive technological interventions by a customized approach.


Subject(s)
Fruit and Vegetable Juices/analysis , Hot Temperature , Malus , Pasteurization/methods , Phenols/pharmacology , Ultrasonics , Hydrogen-Ion Concentration , Phenols/chemistry
9.
Plant Physiol Biochem ; 141: 95-104, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31136935

ABSTRACT

Biostimulants improve yield, quality, and stress acclimation in crops. In this work, we tested the possibility of using phenolics-rich extracts from spelt (Triticum dicoccum L.) husks to attenuate the effects of salt stress (100-200 mM NaCl) in maize. Two methanolic extracts were prepared from the soluble-conjugated (SC), and the insoluble-bound (IB) phenolic acid fractions of the spelt husk, and their effects were investigated on several stress-associated biochemical parameters, such as proline, lipid peroxidation, H2O2, GSH levels, and ion content. Results show that SC and IB fractions of husk extracts behaved very differently, no doubt due to their greatly divergent chemical composition, as revealed by both GC-MS and HPLC analyses. The efficacy of treatments in mitigating salt stress was also dose- and timing-dependent. IB, even at the lower concentration tested, was able to recover the performance of stressed plants in terms of growth, photosynthetic pigments content, and levels of salt stress markers. Recovery of shoot growth to control levels and reduction of stress-induced proline accumulation occurred regardless of whether plants were pre-treated or post-treated with IB, whereas only pre-treatment with the higher dose of IB was effective in mitigating oxidative stress. Although in some cases SC and even methanol alone exerted some positive effects, they could also be deleterious whereas IB never was. Overall, results indicate that a polyphenol-containing extract obtained from spelt by-products can behave as biostimulant in maize plants and can mitigate their response to salt stress, by acting on different biochemical targets.


Subject(s)
Plant Extracts/pharmacology , Polyphenols/pharmacology , Salt Stress , Triticum/chemistry , Zea mays/chemistry , Antioxidants/chemistry , Crops, Agricultural/chemistry , Gas Chromatography-Mass Spectrometry , Glutathione/chemistry , Hydrogen Peroxide/chemistry , Lipid Peroxidation , Oxidative Stress , Photosynthesis , Phytochemicals/chemistry , Pigmentation , Plant Leaves/chemistry , Plant Proteins/chemistry , Potassium/chemistry , Proline/chemistry , Salt Tolerance , Sodium/chemistry
10.
J Chromatogr A ; 1597: 63-75, 2019 Jul 19.
Article in English | MEDLINE | ID: mdl-30885401

ABSTRACT

Jatropha curcas L. is an inedible plant whose seed oil is an interesting source for biodiesel production. Seed cake, the main byproduct remaining (about 70% w/w) after the oil extraction process, has a high nutritional value but the presence in Jatropha curcas seed of phorbol esters (PEs), a family of toxic compounds with a tigliane skeleton, prevents application of seed cake and other byproducts (e.g. glycerin) in animal feed without an efficient detoxification. Considering the high toxicity of PEs, it is important to have a sensitive analytical method to evaluate the presence of these compounds in Jatropha curcas derivatives. In this paper we present the study of the ESI-MS/MS fragmentation pattern of the [M+Na]+ ion at m/z 733.5 of the six known PEs, namely Jatropha factors (JFs) C1-C6, which allowed to tentatively identify a series of characteristic and specific fragment ions useful to reveal the presence of JFs in Jatropha curcas seed oil, distinguish them from each other, and identify new PEs (J1-J4). Moreover, the substitution of the usual acetonitrile/water as mobile phase with a mixture of methanol/water (85:15, v/v) allowed to increase the signal of the sodium adduct of about 50-fold during the HPLC-ESI-MS/MS analysis.


Subject(s)
Animal Feed/adverse effects , Chromatography, High Pressure Liquid , Food Analysis/methods , Phorbol Esters/analysis , Plant Oils/chemistry , Tandem Mass Spectrometry , Animal Feed/analysis , Animals , Biofuels , Glycerol/chemistry , Jatropha/chemistry , Seeds/chemistry
11.
Food Res Int ; 119: 596-604, 2019 05.
Article in English | MEDLINE | ID: mdl-30884693

ABSTRACT

The aim of this work was the study of the best conditions for obtaining a callus culture from the pulp of Acca sellowiana, and to perform a quali-quantitative analysis of the secondary metabolites yielded by the in vitro callus culture. To this end, callus was induced on both Murashige and Skoog and Gamborg B5 media containing various combinations of growth regulators. Three previously undescribed ursane-type triterpenoids, 2α,3ß,6α,23-tetrahydroxy-18α,19α-urs-20-en-28-oic acid, 2α,3ß,23-trihydroxy-18α,19α-urs-20-en-28-oic acid and 2α,3ß,6ß,23-tetrahydroxy-18α,19α-urs-20-en-28-oic acid were isolated from the methanolic extract of A. sellowiana culture and characterized by 1D and 2D NMR experiments. Moreover, the quali-quantitative analysis (ESI-MSn and GC-MS) also showed the presence of ß-sitosterol, phloridzin, oleanolic, ursolic, 3ß-hydroxy-18α,19α-urs-20-en-28-oic, maslinic, corosolic, 2α,3ß-dihydroxy-18α,19α-urs-20-en-28-oic, and tormentic acid.


Subject(s)
Fruit/chemistry , Myrtaceae/chemistry , Plant Extracts/chemistry , Triterpenes/chemistry , Gas Chromatography-Mass Spectrometry , Myrtaceae/metabolism , Oleanolic Acid , Phlorhizin , Phytochemicals/chemistry , Secondary Metabolism , Sitosterols , Ursolic Acid
12.
Food Chem ; 283: 177-182, 2019 Jun 15.
Article in English | MEDLINE | ID: mdl-30722858

ABSTRACT

The sterols and triterpene dialcohols composition is an important parameter to assess the authenticity of the high value and prone to adulteration extra virgin olive oil. The official methods used to carry out this analysis are time-consuming, labor-intensive and require a high amount of solvents. In this work a simple and time-saving method, based on two solid phase extraction (SPE) steps was developed. After oil saponification, the unsaponifiable matter was purified by polymeric SPE and then the sterols and triterpene dialcohols were isolated by an in-house packed small particle silica gel SPE and analyzed by GC-FID. Results obtained analyzing a sample of extra virgin olive oil, olive oil and refined olive pomace oil with the proposed method showed a good agreement with those obtained with the International Olive Council (IOC) official method. Thus, the use of the proposed method allows a rapid screening for extra virgin olive oils authentication.


Subject(s)
Alcohols/analysis , Olive Oil/chemistry , Solid Phase Extraction/methods , Sterols/analysis , Triterpenes/analysis , Chromatography, Gas/methods , Chromatography, High Pressure Liquid , Food Contamination/analysis , Particle Size , Phytosterols , Polymers , Silica Gel , Solvents
13.
Food Chem ; 230: 604-610, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28407957

ABSTRACT

A rapid and sensitive HPLC-APCI-MS/MS method for the determination of cholesterol oxidation products (COPs) in milk powder based foods is reported. The method consists in the direct saponification of the sample and purification of oxysterols by reversed phase C18-SPE followed by HPLC-MS/MS analysis. By this procedure, the extraction and enrichment of oxysterols are combined in a unique step, reducing sample manipulation and the possible formation of artifacts. LOD and LOQ were in the concentration ranges of 2-8ngg-1 and 8-30ngg-1, respectively. The precision (CV%) was in the range 10-36% in fresh samples with a total COPs amount from 212 to 645ngg-1 and 6-14% for an oxidized sample with a higher amount (3651ngg-1). The recovery ranged from 74±8% for 7-ketocholesterol to 101±12% for 7α-hydroxycholesterol at 200ngg-1 and from 82±2% for 7-ketocholesterol to 117±10% for 5α,6α-epoxycholesterol at 500ngg-1 spiked levels, respectively.


Subject(s)
Chromatography, High Pressure Liquid/methods , Food Analysis/methods , Milk/chemistry , Solid Phase Extraction/methods , Tandem Mass Spectrometry/methods , Animals , Oxidation-Reduction
14.
Phytochem Anal ; 28(1): 5-15, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27688003

ABSTRACT

INTRODUCTION: Very rarely fruit pulp has been used in in vitro culture to produce secondary metabolites useful in promoting health. OBJECTIVES: The aims of this work were the study of the best conditions to obtain the callus cultures from the pulp of two varieties of apples, Golden Delicious (GD) and "Mela Rosa Marchigiana" (MRM), and the quali-quantitative analysis of secondary metabolites produced by the two in vitro callus cultures. METHODOLOGY: Callus was induced on both Murashige and Skoog and Gamborg B5 media containing various combinations of supplements. To achieve the maximum recovery of secondary metabolites produced, preliminary extraction tests were carried out on GD apple culture using two different organic solvents (MeOH and EtOAc). The quali-quantitative analysis of the methanolic extract of both cultures was carried out by ESI-MSn and GC-MS techniques. RESULTS: The GC-MS analysis revealed the presence of triterpenic acids, in particular, oleanolic, ursolic, maslinic, pomolic, tormentic, corosolic and annurcoic acid along with a phytosterol, ß-sitosterol. In addition, GD callus culture produced phloridzin, absent in the MRM culture. In this last culture, however, the total amount of secondary metabolites was markedly higher. The in vivo production of these bioactive compounds were also quantified in the GD and MRM apple pulps. CONCLUSION: Apple pulps produced higher amounts of triterpenic acids in vitro than in vivo. The present work can be considered a method to amplify the production of important secondary metabolites which exert beneficial effects on human health. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Malus/metabolism , Triterpenes/metabolism , Gas Chromatography-Mass Spectrometry , Malus/classification , Spectrometry, Mass, Electrospray Ionization
15.
Nat Prod Commun ; 10(6): 1037-42, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26197546

ABSTRACT

The in vitro antifungal activity was determined of an ethanolic extract of Vitis vinifera L. tendrils (TVV) against ten plant pathogenic fungi, using the agar dilution method; activity was shown against all tested fungi. Fusarium species were the most sensitive with MIC values ranging from 250 to 300 ppm, while the basidiomycete fungus Rhizoctonia solani was the most resistant, with a MIC value of 500 ppm. Electrospray ionization tandem mass spectrometry (ESI-MS(n)) was used to obtain qualitative information on the main components of TVV. The high amount of polyphenolic compounds contained in TVV is likely to contribute significantly to its antifungal activity.


Subject(s)
Antifungal Agents/pharmacology , Plant Extracts/pharmacology , Vitis/chemistry , Antifungal Agents/chemistry , Fusarium/drug effects , Fusarium/growth & development , Microbial Sensitivity Tests , Plant Diseases/microbiology , Plant Extracts/chemistry , Rhizoctonia/drug effects , Rhizoctonia/growth & development , Spectrometry, Mass, Electrospray Ionization
16.
Food Chem ; 145: 168-72, 2014 Feb 15.
Article in English | MEDLINE | ID: mdl-24128463

ABSTRACT

Coffea arabica beans were roasted in an oven at 200 °C for increasing lengths of time under vacuum (i.e. 0.15 kPa). The samples were then analysed for colour, weight loss, acrylamide concentration and sensory properties. Data were compared with those obtained from coffee roasted at atmospheric pressure (i.e. conventional roasting), as well as at atmospheric pressure for 10 min followed by vacuum treatment (0.15 kPa; i.e. conventional-vacuum roasting). To compare the different treatments, weight loss, colour and acrylamide changes were expressed as a function of the thermal effect received by the coffee beans during the different roasting processes. Vacuum-processed coffee with medium roast degree had approximately 50% less acrylamide than its conventionally roasted counterpart. It was inferred that the low pressure generated inside the oven during the vacuum process exerted a stripping effect preventing acrylamide from being accumulated. Vacuum-processed coffee showed similar colour and sensory properties to conventionally roasted coffee.


Subject(s)
Acrylamide/metabolism , Coffea/metabolism , Acrylamide/analysis , Coffea/chemistry , Hot Temperature , Seeds/chemistry , Vacuum
17.
J Mass Spectrom ; 48(11): 1136-49, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24259202

ABSTRACT

N-Boc/Fmoc/Z-N'-formyl-gem-diaminoalkyl derivatives, intermediates particularly useful in the synthesis of partially modified retro-inverso peptides, have been characterized by both positive and negative ion electrospray ionization (ESI) ion-trap multi-stage mass spectrometry (MS(n)). The MS(2) collision induced dissociation (CID) spectra of the sodium adduct of the formamides derived from the corresponding N-Fmoc/Z-amino acids, dipeptide and tripeptide acids show the [M + Na-NH2CHO](+) ion, arising from the loss of formamide, as the base peak. Differently, the MS(2) CID spectra of [M + Na](+) ion of all the N-Boc derivatives yield the abundant [M + Na-C4H8](+) and [M + Na-Boc + H](+) ions because of the loss of isobutylene and CO2 from the Boc protecting function. Useful information on the type of amino acids and their sequence in the N-protected dipeptidyl and tripeptidyl-N'-formamides is provided by MS(2) and subsequent MS(n) experiments on the respective precursor ions. The negative ion ESI mass spectra of these oligomers show, in addition to [M-H](-), [M + HCOO](-) and [M + Cl](-) ions, the presence of in-source CID fragment ions deriving from the involvement of the N-protecting group. Furthermore, MS(n) spectra of [M + Cl](-) ion of N-protected dipeptide and tripeptide derivatives show characteristic fragmentations that are useful for determining the nature of the C-terminal gem-diamino residue. The present paper represents an initial attempt to study the ESI-MS behavior of these important intermediates and lays the groundwork for structural-based studies on more complex partially modified retro-inverso peptides.


Subject(s)
Amino Acids/chemistry , Diamines/chemistry , Fluorenes/chemistry , Peptides/analysis , Peptides/chemistry , Spectrometry, Mass, Electrospray Ionization/methods
18.
Food Chem ; 135(4): 2687-93, 2012 Dec 15.
Article in English | MEDLINE | ID: mdl-22980859

ABSTRACT

In this work, a rapid and reliable purification method based on a single mixed solid phase extraction (SPE) column, for the determination of acrylamide in roasted coffee by liquid chromatography-tandem mass spectrometry, was developed. Deuterium labelled d(3)-acrylamide was used as internal standard. Acrylamide was extracted by 10 mL of water and the extract purified by a single SPE column consisting of 0.5 g of an in-house prepared mixture of C18, strong cation (SCX) and anion exchange (SAX) sorbents in the ratio 2/1.5/1.5 (w/w/w). The amount of the three sorbents was optimised in order to eliminate the main interfering compounds present in coffee extracts, such as melanoidins, trigonelline, chlorogenic acids and caffeine. The SPE procedure was very simple and consisted of pushing 1 mL of an aqueous coffee extract through the SPE column followed by 1 mL of water which was collected for the analysis. The method was tested on six samples of roasted coffee of different composition and roasting level. The repeatability of the method, expressed as relative standard deviation (n=6), was lower than 5%. The recovery of acrylamide at three spiked levels ranged from 92% to 95%. The limits of detection (LOD) and quantitation (LOQ) were 5 and 16 µg kg(-1), respectively.


Subject(s)
Acrylamide/analysis , Chromatography, High Pressure Liquid/methods , Coffea/chemistry , Coffee/chemistry , Solid Phase Extraction/methods , Tandem Mass Spectrometry/methods , Adsorption , Food Handling , Limit of Detection , Resins, Synthetic/chemistry , Seeds/chemistry , Solid Phase Extraction/instrumentation
19.
Rapid Commun Mass Spectrom ; 23(11): 1607-18, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19408275

ABSTRACT

Underivatized oligosaccharides were analyzed by electrospray ionization (ESI) using a linear ion trap mass spectrometer in the negative ion mode with post-column addition of an aqueous solution of formic acid. Under these conditions all oligosaccharides showed the presence of the corresponding formate adduct [M + HCOO](-) with high intensity and easy subsequent low-energy collision-induced dissociation (CID) fragmentation using successive MS(n) experiments. A careful examination of the mass spectra obtained from these MS(n) experiments pointed out some significant differences useful to identify and quantify the single components in mixtures of coeluted disaccharides. This new sensitive and rapid method was successfully applied to the quantification of oligosaccharides in some juices minimizing sample handling.


Subject(s)
Chromatography, Liquid/methods , Formates/chemistry , Oligosaccharides/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Chromatography, Liquid/instrumentation , Spectrometry, Mass, Electrospray Ionization/instrumentation , Spectrum Analysis
20.
Anal Bioanal Chem ; 376(5): 659-67, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12802575

ABSTRACT

The composition of the surface waxes of three apple ( Malus domesticaL.) cultivars ("Florina", "Golden B" and "Ozark Gold") has been studied by means of spectroscopic and GC-MS analysis of the class-fractionated mixture of components. Odd n-alkanes, mainly C(27) and C(29) molecules, are prevalent in the saturated fraction. Small concentrations of alkenes were also found; the C(28:1) component is strongly (72%) in excess over the other 1-alkenes. Straight-chain esters (mainly of palmitic acid) of saturated primary alcohols (C(18)-C(30)) were also detected; whereas the acyl moiety is made up essentially of an even number of carbons, the alcohol counterpart does not exhibit this characteristic. Aldehydes are present (C(20)-C(30)) with the homologue patterns C(26)-C(30) most strongly represented. Straight-chain free secondary alcohols characterize the waxes of "Florina" and "Ozark Gold"; the hydroxy function is located far from the extremity of the carbon framework. Outstanding is the presence of three alcohols with 29 carbon centres. These alcohols are accompanied by free straight-chain primary alcohols, mainly with even-numbered carbon chains in the range C(26)-C(30). Free fatty acids are present; all of have a framework of even-numbered carbon chains mainly in the range C(16)-C(20). C(18:1) (oleic acid) is well represented.


Subject(s)
Fruit/chemistry , Gas Chromatography-Mass Spectrometry/methods , Malus/chemistry , Malus/classification , Waxes/analysis , Waxes/chemistry , Alcohols/analysis , Alcohols/chemistry , Esters/analysis , Esters/chemistry , Plant Extracts/analysis , Plant Extracts/chemistry , Species Specificity , Spectroscopy, Fourier Transform Infrared
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