Electrospray Ionization Ion Trap Mass Research Articles

Cu and Zn Interactions with Peptides Revealed by High-Resolution Mass Spectrometry.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by abnormal extracellular amyloid-beta (Aβ) peptide depositions in the brain. Among amorphous aggregates, altered metal homeostasis is considered a common risk factor for neurodegeneration known to accelerate plaque formation. Recently, peptide-based drugs capable of inhibiting amyloid aggregation have achieved unprecedented scientific and pharmaceutical interest. In response to metal ions binding to Aβ peptide, metal chelation was also proposed as a therapy in AD. The present study analyzes the interactions formed between NAP octapeptide, derived from activity-dependent neuroprotective protein (ADNP), amyloid Aβ(9–16) fragment and divalent metal ions such as Cu and Zn. The binding affinity studies for Cu and Zn ions of synthetic NAP peptide and Aβ(9–16) fragment were investigated by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ion trap mass spectrometry (ESI-MS) and atomic force microscopy (AFM). Both mass spectrometric methods confirmed the formation of metal–peptide complexes while the AFM technique provided morphological and topographic information regarding the influence of metal ions upon peptide crystallization. Our findings showed that due to a rich histidine center, the Aβ(9–16) fragment is capable of binding metal ions, thus becoming stiff and promoting aggregation of the entire amyloid peptide. Apart from this, the protective effect of the NAP peptide was found to rely on the ability of this octapeptide to generate both chelating properties with metals and interactions with Aβ peptide, thus stopping its folding process.

Impact of instrumental settings in electrospray ionization ion trap mass spectrometry on the analysis of multi-CH3-/CD3-isotopologs in cellulose ether analysis: a quantitative evaluation

Exact quantification of the molar ratios of isotopologous mixed O-methyl-O-methyl-d3-cellooligosaccharides (COS) comprising all combinations from fully methylated to fully deuteromethylated constituents within an individual degree of polymerization (DP) is the key step in the analysis of the substituent distribution over the polymer chains in methyl celluloses (MC). Deuteromethylation of MC is performed to level chemical differences, but due to a m/z range of 3 DP·ΔMe/Me-d3, bias during MS measurement cannot certainly be excluded. Therefore, ionization, ion transportation, and ion storage were studied with an electrospray ionization ion trap mass spectrometer (ESI-IT-MS) using binary equimolar mixtures of per-O-Me- and per-O-Me-d3-COS, defining the border cases of a particular Me/Me-d3-profile. Reference data of their molar ratio were determined after reductive amination with m-amino benzoic acid by HPLC-UV. COS of DP2–6 were measured as their sodium adducts at c = 10−6 M by syringe pump infusion. The impact of the RF voltage of the ion trap (TD), the octopole RF and DC voltages, and the Cap Exit potential on absolute and relative ion intensities were studied. Adapting the Cap Exit voltage was essential for correct quantification of DP2, while all COS of higher DP behaved insensitive with respect to bias. To check whether any bias occurs in the electrospray ionization process of the isotopologs, concentration-dependent measurements were performed with optimized instrumental settings for each DP. Intensity ratios IR = I (Me-d3)/I (Me) did not show any concentration-dependent trend and no selective ion suppression. Its decrease with DP observed under usually applied standard conditions (smart mode) is a consequence of discrimination according to m/z and can be overcome by appropriate instrumental settings of Oct 2 DC and TD. IR between 0.971 ± 0.008 and 1.040 ± 0.009 with no trend for DP (2-6) were obtained by averaging all measurements in the range 2 · 10−7 to 2 · 10−5 M total concentration. The DP-related optimized settings were applied to two MCs and compared with the results obtained under so far applied standard conditions.Graphical abstract

Thymosin β4 and β10 are highly expressed at the deep infiltrative margins of colorectal cancer - A mass spectrometry analysis.

Colorectal cancer (CRC) is a complicated tumor, involving several oncogenic signaling pathways, and with a molecular mechanism not fully understood yet. The implication of thymosin β4 (Tβ4) with tumor insurgence and in migration of CRC cells was evidenced in the past with different methodologies, while Tβ10 connection with CRC has been sporadically investigated. This study focused on the implication of both types of thymosin in CRC progression and invasion by analyzing the changes in their levels according to different zones of the tumor, and to Dukes stage and budding index. Tβ4 and Tβ10 were analyzed in deep and superficial tumor samples, and normal mucosa from 18 patients. Concentrations of Tβ4 and Tβ10 have been measured by high-pressure liquid chromatography (HPLC) coupled to electrospray-ion trap mass spectrometry (ESI-IT-MS). MS data were compared by t-test and ANOVA statistical analysis. Identification of thymosin and their proteoforms has been performed by HPLC-high resolution-ESI-IT-MSMS. Both Tβ4 and Tβ10, exhibited intra-tumoral quantitative differences, being upregulated in the deep part of the CRC. They exhibited, moreover, strong association with the Dukes stage and the budding grade, being more concentrated in patients at Dukes stage B and with budding index "2". The results obtained in the present investigation encouraged the hypothesis that the two thymosin are involved in colorectal cancer progression, and in promoting cancer invasion. Thus, they are good candidates to be diagnostic/prognostic biomarkers and therapy targets.

Carpobrotus edulis (L.) N.E.Br. extract as a skin preserving agent: From traditional medicine to scientific validation

ObjectiveCarpobrotus edulis (L.) N.E.Br. is a succulent perennial plant native to South Africa and grows invasively in the Mediterranean basin. It is commonly used for the treatment of various diseases, including skin wound healing and regeneration, for which experimental validation is lacking. We therefore evaluated the skin healing properties by testing a C. edulis aqueous leaf extract (CAE) on cell cultures and in enzymatic assays. MethodsMicro-morphological analysis of leaves was carried out using scanning electron microscopy and light microscopy. Phytochemical features and antioxidant activity of CAE were evaluated by reversed-phase liquid chromatography coupled with diode array detection and electrospray ion trap mass spectrometry (RP-LC-DAD-ESI-MS), and in vitro cell-free assays. Biological activities were evaluated using keratinocytes and fibroblasts, as well as elastase, collagenase, and hyaluronidase. ResultsCAE showed high carbohydrates (28.59% ± 0.68%), total phenols ([101.9 ± 6.0] g gallic acid equivalents/kg dry extract [DE]), and flavonoids ([545.9 ± 26.0] g rutin equivalents/kg DE). RP-LC-DAD-ESI-MS revealed the predominant presence of hydroxycinnamic acids (51.96%), followed by tannins (14.82%) and flavonols (11.32%). The extract was not cytotoxic, had a strong and dose-dependent antioxidant activity, and inhibited collagenase (> 90% at 500 µg/mL) and hyaluronidase (100% at 1000 µg/mL). In cell culture experiments, CAE increased wound closure and collagen production, which was consistent with its high polyphenol content. ConclusionOur data support the use of the C. edulis for skin care and the treatment of skin problems. Moreover, use of C. edulis for skin care purposes could be an eco-friendly solution to reduce its invasiveness in the environment.

A targeted prenylation analysis by a combination of IT-MS and HR-MS: Identification of prenyl number, configuration, and position in different subclasses of (iso)flavonoids

Prenylated (iso)flavonoids are potent bioactive compounds found in the Fabaceae family. Analysis and quantification of this type of phytochemicals is challenging due to their large structural diversity. In this study, the fragmentation of prenylated (iso)flavonoids was investigated using electrospray ionization ion trap mass spectrometry (ESI-IT-MSn) with fragmentation by collision induced dissociation (CID) in combination and Orbitrap-MS (ESI-FT-MS2) with fragmentation by higher energy C-trap dissociation (HCD). With this combination of IT-MSn and high resolution MS (FT-MSn), it was possible to determine the fragmentation pathways and characteristic spectral features of different subclasses of prenylated (iso)flavonoid standards, as well as characteristic fragmentations and neutral losses of different prenyl configurations. Based on our findings, a decision guideline was developed to (i) identify (iso)flavonoid backbones, (ii) annotate prenyl number, (iii) configuration, and (iv) position of unknown prenylated (iso)flavonoids, in complex plant extracts. In this guideline, structural characteristics were identified based on: (i) UV absorbance of the compound, (ii) mass-to-charge (m/z) ratio of the parent compound; (iii) ratio of relative abundances between neutral losses 42 and 56 u in MSn; (iv) retro-Diels-Alder (RDA) fragments, neutral losses 54 and 68 u, and the ratio [M+H–C4H8]+/[M+H]+. Using this guideline, 196 prenylated (iso)flavonoids were annotated in a Glycyrrhiza glabra root extract. In total, 75 skeletons were single prenylated, 104 were double prenylated, and for merely 17 skeletons prenyl number could not unambiguously be annotated. Our prenylation guideline allows rapid screening for identification of prenylated (iso)flavonoids, including prenyl number, configuration, and position, in complex plant extracts. This guideline supports research on these bioactive compounds in the areas of plant metabolomics and natural products.

Eco-Friendly Pharmaceutical Analysis of Rifaximin in Tablets by HPLC-MS and Microbiological Turbidimetry.

Rifaximin, an antimicrobial used for the treatment of various diseases, lacks analytical methods in official compendia for evaluation of the final product. This paper presents an eco-friendly protocol for rifaximin tablets by high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The method was completely validated according to the International Conference on Harmonization guidelines and developed following the concept of Quality by Design. The separation was achieved using a C18 column, purified water +0.1% glacial acetic acid and ethyl alcohol, 52:48 (v/v), as mobile phase, 0.9mLmin-1 at 290nm and ambient room temperature. Mass spectral analyses were performed using electrospray ionization (ESI) ion source and ion trap mass analyzer. The method was linear over the concentration range of 5-50μgmL-1. The sample was subjected to acidic, basic, neutral, oxidative and photolytic degradation. Degradation products did not interfere in the quantification of the rifaximin, so the method can be considered indicative of stability. Degradation products were also evaluated individually by microbiological method using Escherichia coli. The validated method could be used promisingly as green analytical strategies for detection and quantification of rifaximin in tablets.

Distribution of 5,6-dihydro-α-pyrones by electrospray ionization ion trap mass spectrometry in different aerial parts of Hyptis monticola

Hyptis monticola Mart. ex Benth. (Lamiaceae) is an endemic species of altitude regions of Brazil. From the leaves of this plant, two 5,6-dihydro-α-pyrones, named monticolides A and B, have been reported as cytotoxic agents against different tumor cell lines. The isolation by high-speed countercurrent chromatography in combination with recycling preparative high-performance liquid chromatography of the undescribed monticolides C-F is presented. These compounds corresponded to a series of related monticolide derivatives differing from each other by the number of acyl substituents. Their characterization by mass spectrometry and nuclear magnetic resonance is also presented, in conjunction with an evidence by a simple chemical correlation for their absolute stereochemistry. The distribution of these chemical markers in extracts of flowers, leaves and branches collected in different seasons by electrospray ionization ion trap mass spectrometry in positive mode was analyzed. Multivariate data analyses indicated that seasonality affects monticolide concentrations in different organs of the aerial parts. Monticolides A-F seem to be present as the original markers of the analyzed plant. However, mono-, di- and triacetylated monticolides can undergo acid-catalyzed transesterifications and their natural yields estimated were affected during the isolation procedures.

Phytochemical Profile, Safety Assessment and Wound Healing Activity of Artemisia absinthium L.

The aim of study was to validate, by in vitro and in vivo studies, the traditional use for wound-healing activity of Artemisia absinthium L. Reversed-phase liquid chromatography coupled with diode array detection and electrospray ion trap mass spectrometry (RP-LC-DAD-ESI-MS) analysis allowed to identify eleven polyphenols with chlorogenic acid as the most abundant compound (3.75 g/100 g of dry extract). After that, antibacterial activity as well as acute dermal and oral toxicity were assessed in animal models. In order to investigate the wound-healing activity of A. absinthium methanol extract, two ointments were formulated (MEO 5% and 10%). The ointment with the highest concentration of plant extract (10%) showed a statistically significant effect on the rats wound contraction, similar to that exerted by the reference drug Cicatryl-Bio. Moreover, A. absinthium methanol extract showed the best antibacterial activity against the Gram-negative Escherichia coli ATCC 10536 (MIC 1.25–2.5 mg/mL) and the Gram-positive Staphylococcus aureus ATCC 6538 (0.31–0.625 mg/mL). The absence of oral and topical toxicity of the treated animals allowed to establish the safety of the ointments. Overall, data collected in the present study support and validate the use of A. absinthium as a wound healing agent in the Algerian traditional medicine.

Schisandra rubriflora Plant Material and In Vitro Microshoot Cultures as Rich Sources of Natural Phenolic Antioxidants.

Schisandra rubriflora is a dioecious, underestimated medicinal plant species known from traditional Chinese medicine. The present study was aimed at characterising the polyphenolic profile composition and the related antioxidant capacity of S. rubriflora fruit, stem and leaf and in vitro microshoot culture extracts. Separate analyses of material from female and male specimens were carried out. This study was specifically aimed at detailed characterisation of the contribution of phenolic compounds to overall antioxidant activity using ultra-high-performance liquid chromatography with a photodiode array detector coupled to electrospray ionization ion trap mass spectrometry (UHPLC-DAD-ESI-MS3) and a high-performance liquid chromatography-diode array detector (HPLC-DAD). Using UHPLC-DAD-ESI-MS3, twenty-seven phenolic compounds from among phenolic acids and flavonoids were identified. Concentrations of three phenolic acids (neochlorogenic, chlorogenic and cryptochlorogenic acids) and eight flavonoids (hyperoside, rutoside, isoquercitrin, guaijaverin, trifolin, quercetin, kaempferol, and isorhamnetin) were determined using HPLC-DAD using reference standards. The highest total phenolic content was confirmed for the stem and leaf extracts collected in spring. The contents of phenolic compounds of in vitro biomasses were comparable to that in the fruit extracts. The methanolic extracts from the studied plant materials were evaluated for their antioxidant properties using various in vitro assays, namely free radicals scavenging estimation using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), ferric-reducing antioxidant power (FRAP) and cupric-reducing antioxidant capacity (CUPRAC) as well as QUick, Easy, New, CHEap, and Reproducible CUPRAC (QUENCHER-CUPRAC) assays. A close relationship between the content of polyphenolic compounds in S. rubriflora and their antioxidant potential has been documented.

Silver Nanoparticle Trypsin Corona Formation and the Impacts on Enzymatic Potency

Herein, the protein corona formation on the spherical metal nanoparticles was studied to investigate the possible effects of silver nanoparticles (AgNPs) on the protein activity and conformation. The digestion capability of trypsin was monitored on the human serum albumin (HSA) at standard enzymatic hydrolysis conditions in the absence and presence of different concentrations of AgNPs. So the ratio of enzyme:HSA, the duration and the temperature of nanoparticle treatment were evaluated. The activity of treated trypsin molecules, in the form of hard (HC) and soft corona (SC) were studied using sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE), and nano liquid chromatography electrospray (ion trap) mass spectrometry (nano LC-ESI/MS, LC-ESI/MS). In addition the characteristics of silver nanoparticles and the formation of HSA corona on the nanoparticle surface were monitored using ultra-violet/visible spectroscopy (UV-Vis), Dynamic light scattering (DLS) and fluorescence spectrophotometry. The results demonstrated that not only the corona formation but also the AgNPs/Trypsin interaction, decreases the hydrolysis potency of trypsin. Furthermore, the encountering of the AgNPs/HSA could influence both nanoparticles and HSA molecule features. Accompanied with fluorescence study, that the HSA secondary structure. Also LC-ESI/MS data revealed the most affected HSA triptics have α-helix structure.

Quantum chemical mass spectrometry: Ab initio study of b2 -ion formation mechanisms for the singly protonated Gln-His-Ser tripeptide.

Both amide bond protonation triggering peptide fragmentations and the controversial b2 -ion structures have been subjects of intense research. The involvement of histidine (H), with its imidazole side chain that induces specific dissociation patterns involving inter-side-chain (ISC) interactions, in b2 -ion formation was investigated, focusing on the QHS model tripeptide. To identify the effect of histidine on fragmentations issued from ISC interactions, QHS was selected for a comprehensive analysis of the pathways leading to the three possible b2 -ion structures, using quantum chemical calculations performed at the DFT/B3LYP/6-311+G* level of theory. Electrospray ionization ion trap mass spectrometry allowed the recording of MS2 and MS3 tandem mass spectra, whereas the Quantum Chemical Mass Spectrometry for Materials Science (QCMS2 ) method was used to predict fragmentation patterns. Whereas it is very difficult to differentiate among protonated oxazolone, diketopiperazine, or lactam b2 -ions using MS2 and MS3 mass spectra, the calculations indicated that the QH b2 -ion (detected at m/z 266) is probably a mixture of the lactam and oxazolone structures formed after amide nitrogen protonation, making the formation of diketopiperazine less likely as it requires an additional step for its formation. In contrast to glycine-histidine-containing b2 -ions, known to be issued from the backbone-imidazole cyclization, we found that interactions between the side chains were not obvious to perceive, neither from a thermodynamics nor from a fragmentation perspective, emphasizing the importance of the whole sequence on the dissociation behavior usually demonstrated from simple glycine-containing tripeptides.

Green Extraction of Alkaloids and Polyphenols from Peumus boldus Leaves with Natural Deep Eutectic Solvents and Profiling by HPLC-PDA-IT-MS/MS and HPLC-QTOF-MS/MS.

Peumus boldus Mol., is a Chilean medicinal tree used for gastrointestinal and liver diseases. Such medicinal properties are associated with the presence of bioactive flavonoids and aporphine alkaloids. In this study, a new green and efficient extraction method used seven natural deep eutectic solvents (NADES) as extraction media. The extraction efficiency of these NADES was assessed, determining the contents of boldine and total phenolic compounds (TPC). Chemical profiling of P. boldus was done by high-performance liquid chromatography coupled to photo diode array detector and electrospray ion-trap mass spectrometry (HPLC-PDA-ESI-IT/MS) and electrospray ionization quadrupole time-of-flight high-resolution mass spectrometry (HPLC-ESI-QTOF-MS). Among the NADES tested, NADES4 (choline chloride-lactic acid) and NADES6 (proline-oxalic acid) enable better extraction of boldine with 0.427 ± 0.018 and 2.362 ± 0.055 mg of boldine g−1 of plant, respectively. Extraction of boldine with NADES4 and NADES6 was more efficient than extractions performed with methanol and water. On the other hand, the highest TPC were obtained using NADES6, 179.442 ± 3.79 mg of gallic acid equivalents (GAE g−1). Moreover, TPC in extracts obtained with methanol does not show significant differences with NADES6. The HPLC-PAD-MS/MS analysis enable the tentative identification of 9 alkaloids and 22 phenolic compounds. The results of this study demonstrate that NADES are a promising green extraction media to extract P. boldus bioactive compounds and could be a valuable alternative to classic organic solvents.

Fragmentation pathways of deprotonated amide‐sulfonamide CXCR4 inhibitors investigated by ESI‐IT‐MSn, ESI‐Q‐TOF‐MS/MS and DFT calculations

Amide-sulfonamides provide a potent anti-inflammatory scaffold targeting the CXCR4 receptor. A series of novel amide-sulfonamide derivatives were investigated for their gas-phase fragmentation behaviors using electrospray ionization ion trap mass spectrometry and quadrupole time-of-flight mass spectrometry in negative ion mode. Upon collision-induced dissociation (CID), deprotonated amide-sulfonamides mainly underwent either an elimination of the amine to form the sulfonyl anion and amide anion or a benzoylamide derivative to provide sulfonamide anion bearing respective substituent groups. Based on the characteristic fragment ions and the deuterium-hydrogen exchange experiments, three possible fragmentation mechanisms corresponding to ion-neutral complexes including [sulfonyl anion/amine] complex (INC-1), [sulfonamide anion/benzoylamide derivative] complex (INC-2) and [amide anion/sulfonamide] complex (INC-3), respectively, were proposed. These three ion-neutral complexes might be produced by the cleavages of S-N and C-N bond from the amide-sulfonamides, which generated the sulfonyl anion (Route 1), sulfonamide anion (Route 2) and the amide anion (Route 3). DFT calculations suggested that Route 1, which generated the sulfonyl anion (ion c) is more favorable. In addition, the elimination of SO2 through a three-membered-ring transition state followed by the formation of C-N was observed for all the amide-sulfonamides.

Structural characterisation of new immunoadjuvant saponins from leaves and the first study of saponins from the bark of Quillaja brasiliensis by liquid chromatography electrospray ionisation ion trap mass spectrometry.

Quillaja brasiliensis (St. A. -Hil. & Tul) Mart (Quillajaceae) is a species native to South America, which is rich in saponins. Saponins are used in different industries, so there is a constant demand for this type of compound. Based on the wide range of applications for the saponins found in this species, notably as immunoadjuvants, we conducted a comprehensive study of this tree and its saponins. The purpose of this work is to complete the characterisation of the immunoadjuvant saponin fraction from Q. brasiliensis leaves and further study the saponin fraction obtained from Q. brasiliensis bark. Saponin fractions were studied using mass spectrometry in combination with classical methods of monosaccharide and methylation analysis. We performed direct infusion and liquid chromatography/electrospray ionisation ion trap multiple-stage mass spectrometry (DI-ESI-IT-MSn and LC-ESI-IT-MS2 ). Seventy-five saponins, 21 from leaves and 54 from bark, were tentatively identified according to their molecular mass, fragmentation pattern and chromatographic behaviour. This work represents the first investigation of saponins from the bark of Q. brasiliensis and some of them presented new structural motifs not previously reported in the genus Quillaja. The efficiency and selectivity of the data dependent LC-MS2 method allowed the rapid profiling of saponins from Q. brasiliensis. The results of the monosaccharide and methylation analysis performed in saponins from Q. brasiliensis fractions and Q. saponaria Molina (Quillajaceae) fraction gives further support to the structures proposed according to the mass spectral data, validating the strategy used in the present work.

Photocatalytic Activity of BiTaO4 Nanoparticles for the Degradation of Methyl Orange Under Visible Light

BiTaO4 nanoparticles were successfully synthesized by the gel-combustion method using polyvinyl alcohol and freshly prepared precursor Ta2O5.nH2O. Materials were characterized by x-ray diffraction and transmission electron microscopy (TEM). With an average grain size of 30 nm, the prepared particle was used to investigate the photocatalytic capacity under the visible light irradiation. The photodegradation process of methyl orange occurred following the pseudo-first order reaction mechanism on the surface of the materials. BiTaO4 nanoparticles which calcined at 750°C presented the best catalytic capacity with the highest rate constant to degrade methyl orange about 5.43 × 10−2 mg l−1 min−1. Besides, the intermediates coming from the photocatalytic degradation of methyl orange were evaluated by liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry (LC/MS). The results showed that the intermediates of degradation reactions of methyl orange were not more toxic than the initial methyl orange. BiTaO4 nanoparticles can mineralize the methyl orange after 60 min of illumination.

Chemical characterization and evaluation of antioxidant and antimicrobial activities of Litchi chinensis sonn

Background: Litchi chinensis is used in traditional Chinese medicine and by Indian medical system. Ethnopharmacological studies show anti-inflammatory, antidiabetic and analgesic activities, among others. However, there are few studies of antimicrobial activity. This study evaluates antimicrobial, antioxidant, and cytotoxicity properties of the lychee's leaves extract (LE) and fractions. Materials and Methods: Extracts were obtained using an exhaustive extraction method with ethanol: Water (7:3 v/v). Subsequently, LE was concentrated in a rotary evaporator. Finally, LE was dried via lyophilization. Fractions were obtained via the partition process. Bioactivity of the LE and fractions (hexane [Hex], ethyl acetate [EtOAc], n-butanol [BuOH], and aqueous [Aq]) from L. chinensis was evaluated through antimicrobial activity using broth microdilution, antioxidant activity via both 1,1-diphenyl-2-picryl-hidrazila assay and ferric reducing capacity and cytotoxicity through 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay. Furthermore, mass spectrometry technique electrospray ionization ion trap mass spectrometry was used to identify the chemical composition of the LE and fractions. Results: Phenolic compounds, such as flavonoids and condensed tannins were the main substances found. Total phenolic and flavonoid contents were higher in EtOAc (541.15 ± 2.4 mg/g and 31.06 ± 0.5 mg/g, respectively). This fraction showed the best results for antioxidant activity (IC50= 3.45 mg/mL) and ferric reducing capacity (20.27% ± 0.11). The LE and fractions showed considerable antimicrobial activity, chiefly against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Proteus mirabilis, with the minimum inhibitory concentration ranging from 50 to 1560 μg/ml. Conclusion: This study revealed that L. chinensis is a source of bioactive compounds potentially useful for pharmaceutical and food industries. Abbreviations Used: LE: Leaves extract, Hex: Hexane fraction, EtOAc: Ethyl acetate fraction, BuOH: n-butanol fraction, Aq: Aqueous fraction, DPPH: 1,1-diphenyl-2-picryl-hidrazila, MTT: 3-(4,5-dimethyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide, ESI-IT-MSn: Electrospray ionization ion trap mass spectrometry, IC50: Median Inhibition Concentration (concentration that reduces the effect by 50%), MIC: Minimum inhibitory concentration, MS/MS: Mass spectrometry, MSn: Tandem mass spectrometry, GAE: Equivalents of gallic acid, QE: Equivalents of quercetin, BHT: Butylated Hydroxy Toluene, UV: Ultraviolet, ATCC: American Type Culture Collection, MHB: Mueller Hinton broth, DMSO: Dimethyl sulfoxide, ANOVA: Analysis of variance, CC50: Cytotoxic concentration 50.

Structural Elucidation of Cisplatin and Hydrated cis-Diammineplatinum(II) Complex Conjugated with Cyanocobalamin by Liquid Chromatography with Electrospray Ionization-Mass Spectrometry and Multistage Mass Spectrometry.

Pt(II)-based derivatives bearing a cyanocobalamin (CNCbl) unit were synthesized in aqueous solutions, and the reaction mixtures were examined by reversed-phase liquid chromatography with electrospray ionization and linear ion trap mass spectrometry (MS). Isotopic pattern analysis, multistage mass-spectra (MS/MS and MS3) interpretation, and differential isotopic labeling were used to establish the chemical composition and to suggest the chemical structures of reaction products. When cisplatin (cis-[PtCl2(NH3)2]) was used as a Pt(II) drug derivative, a coordination bond between diamminemonochloroplatinum(II) and the cyano group of CNCbl, in turn linked covalently to the vitamin Co(III) ion, occurred. The resulting conjugate with a CoIII–CN–PtII bridge was MS detected as a doubly positive charged ion with the prevailing isotopologue at m/z 810.26 (empirical formula [C63H95ClCoIIIN16O14PPt]2+). Likewise, a peak signal centered at m/z 811.26 was observed when 15N-labeled cisplatin cis-[PtCl2(15NH3)2] was used as Pt(II) complex, thus confirming the presence of both the cisplatin amino groups in the conjugate. A bifunctional conjugate was obtained between CNCbl and the cis-diamminediaquaplatinum(II), that is, cis-[Pt(NH3)2(H2O)2]2+; in this case, the planar coordination complex of Pt(II) was also involved in a covalent bond with the oxygen atom of one of the CNCbl amide moieties. The peak signal detected at m/z 792.26 (empirical formula [C63H94CoIIIN16O14PPt]2+) changed to m/z 793.26 when the labeled cis-[Pt(15NH3)2(H2O)2]2+ complex was adopted for conjugation. Comparison between MS/MS spectra allowed an extended structural characterization of both conjugates, as such or 15N-labeled. Two-dimensional heteronuclear (1H–15N) single quantum correlation NMR spectroscopy, applied to 15N-labeled conjugates, supported the hypotheses made on the Pt(II) coordination in both cases.

Modulatory Effect of Polyphenolic Compounds from the Mangrove Tree Rhizophora mangle L. on Non-Alcoholic Fatty Liver Disease and Insulin Resistance in High-Fat Diet Obese Mice.

No scientific report proves the action of the phytochemicals from the mangrove tree Rhizophora mangle in the treatment of diabetes. The aim of this work is to evaluate the effects of the acetonic extract of R. mangle barks (AERM) on type 2 diabetes. The main chemical constituents of the extract were analyzed by high-performance liquid chromatography (HPLC) and flow injection analysis electrospray-iontrap mass spectrometry (FIA-ESI-IT-MS/MS). High-fat diet (HFD)-fed mice were used as model of type 2 diabetes associated with obesity. After 4 weeks of AERM 5 or 50 mg/kg/day orally, glucose homeostasis was evaluated by insulin tolerance test (kiTT). Hepatic steatosis, triglycerides and gene expression were also evaluated. AERM consists of catechin, quercetin and chlorogenic acids derivatives. These metabolites have nutritional importance, obese mice treated with AERM (50 mg/kg) presented improvements in insulin resistance resulting in hepatic steatosis reductions associated with a strong inhibition of hepatic mRNA levels of CD36. The beneficial effects of AERM in an obesity model could be associated with its inhibitory α-amylase activity detected in vitro. Rhizophora mangle partially reverses insulin resistance and hepatic steatosis associated with obesity, supporting previous claims in traditional knowledge.

Metabolite characterization of powdered fruits and leaves from Adansonia digitata L. (baobab): A multi-methodological approach

The metabolite profiling of extracts from Adansonia digitata L. (baobab) fruit pulp and leaf, and the quantification of their major components, was conducted by means of reverse-phase, high-performance liquid chromatography with photodiode array detection, coupled to electrospray ion-trap mass spectrometry (RP-HPLC-PDA-ESI-MS/MS) and high field nuclear magnetic resonance (NMR) spectroscopy. Water-soluble metabolites from chemical classes including sugars, amino acids, organic acids, and phenolic compounds, were identified, in addition to metabolites soluble in organic solvents such as triacylglycerides, sterols, and fatty acids, and most of these were quantified. The profiling of the primary and secondary metabolites of baobab fruit and leaves addresses the limited knowledge of the chemical composition of baobab, and helps support and explain the growing evidence on its nutritional and biological properties, and provide suggestions about the possible uses of baobab fruit and leaves by food, pharmaceutical and cosmetic industries.

Identification of multiple constituents in shuganjieyu capsule and rat plasma after oral administration by ultra-performance liquid chromatography coupled with electrospray ionization and ion trap mass spectrometry

Shuganjieyu (SGJY) capsule is a classical formula widely used in Chinese clinical application. In this paper, an ultra-performance liquid chromatography coupled with electrospray ionization and ion trap mass spectrometry has been established to separate and identify the chemical constituents of SGJY and the multiple constituents of SGJY in rats. The chromatographic separation was performed on a C18 RRHD column (150 × 2.1 mm, 1.8 μm), while 0.1% formic acid–water and 0.1% formic acid–acetonitrile was used as mobile phase. Mass spectral data were acquired in both positive and negative modes. On the basis of the characteristic retention time (Rt) and mass spectral data with those of reference standards and relevant references, 73 constituents from the SGJY and 15 ingredients including 10 original constituents and 5 metabolites from the rat plasma after oral administration of SGJY were identified or tentatively characterized. This study provided helpful chemical information for further pharmacology and active mechanism research on SGJY.