Electrospray Ionization Mass Spectrometry Analysis Research Articles

An integration of UPLC-Q-TOF/MS and chemometrics analysis for the holistic quality evaluation of different geographical Paederia scandens.

Due to the special geographical location and climate of China, there are large differences in the chemical composition and content of Paederia scandens (PS) from different origins, which will have a large impact on its efficacy. An efficient quality control method for PS was established by combining ultra-high-performance liquid chromatography (UPLC) and electrospray ionization mass spectrometry analyses. First, a UPLC-quadrupole time-of-flight mass spectrometry system was employed to identify the chemical composition of PS from seven different origins. Then, the chemical variation in 73 batches of PS samples was subsequently investigated by quantitation of four marker compounds. A total of 15 common compounds were identified in the samples of PS from seven origins. And four of the marker compounds were chosen based on VIP values to characterize the differences between PS samples of different origins. The linearity ranged between 0.005 and 2.500 mg/mL; the correlation coefficients (r2 ) ranged from 0.999 to 1; the limits of detection ranged from 0.013 to 0.033 μg/mL; and the relative standard deviations for repeatability, precisions, and stabilities were below 0.2%, 1.6%, and 0.6%, respectively. The results show that the method can be effective and comprehensive in evaluating the quality of PS from different origins. And this comprehensive strategy proved to be a powerful technique used to differentiate between different geographical herbs.

Synthesis, characterization, and multielectron redox property of pyridine‐coordinated tetra‐Ru‐oxo core sandwich‐type silicotungstate, [(γ‐SiW10O36)2({Ru(IV)(pyridine)}4O4(OH)2]10−

AbstractA pyridine‐coordinated tetra‐Ru‐oxo core sandwich‐type silicotungstate, [(γ‐SiW10O36)2({Ru(IV)(pyridine)}4O4(OH)2]10−, in which four Ru atoms are coordinated by pyridine molecules, was prepared and characterized by single‐crystal X‐ray structure analysis, 1H nuclear magnetic resonance spectroscopy (1H NMR), high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS), infrared (IR) spectroscopy, and elemental analysis. Cyclic voltammetry and ultraviolet–visible (UV‐Vis) electrospectroscopy indicated that the molecule showed multielectron redox processes over a wide pH range (1–12).

Developing a novel exenatide-based incretin mimic (αB-Ex): Expression, purification and structural-functional characterization

Among the various treatments, GLP-1 receptor agonists (incretin mimics) such as liraglutide and exenatide have been well received in treating type 2 diabetes mellitus (T2DM) and obesity. In this study, an exenatide analogue, in which methionine at position 14 substituted with leucine, was ligated to human αB-crystallin (αB-Cry) and then expressed in the bacterial host cells. In the next step, the exenatide analogue was effectively released from the hybrid protein (αB-Ex) and subsequently purified using gel filtration chromatography. The HPLC and electrospray ionization mass spectrometry (ESI-MS) analyses respectively suggested a high purity (more than 97%) and an accurate molecular mass for the exenatide analogue (4168.22 Da and 835.01, z = 5). Also, the molecular mass of the αB-Ex hybrid protein based on the MALDI-TOF analysis was 24,702.162 Da. The secondary structure assessment by the three spectroscopic methods revealed that exenatide analogue and αB-Ex hybrid protein have an α-helix and a β-sheet rich structure, respectively. Also, according to the results of the DLS analysis, the αB-Ex hybrid protein indicated a high tendency to form large oligomeric structures. The NMR assessment suggested that the hybrid protein exists in its folding state. Both exenatide analogue and the αB-Ex hybrid protein revealed a crucial ability to reduce the blood sugar levels in healthy and diabetic mice. They were also capable of inducing insulin secretion to the bloodstream. Overall, our study introduces the αB-Ex hybrid protein as a novel incretin mimic, exerting its biological activity for a longer period of time. It might also be considered a potential drug candidate in the treatment of T2DM.

Seven new 2-(2-phenylethyl) chromone derivatives from agarwood of Aquilaria agallocha with inhibitory effects on nitric oxide production

Seven new 2-(2-Phenethyl) chromone derivatives (1–7), including four 2-(2-Phenethyl) chromones (1–4), one 6, 7, 8 trihydroxy-2-(2-Phenethyl) chromone (5), one acetylated 5, 6, 7, 8-tetrahydroxy-2-(2-Phenethyl) chromone (6), and one chlorine-containing 5, 6, 7, 8-tetrahydro-2-(2-Phenethyl) chromone (7), along with eight known compounds (8–15), were isolated from agarwood originating from Aquilaria agallocha Roxb.. Their structures were determined mainly by high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR) analysis. The absolute configurations of 3–7 were resolved by electronic circular dichroism (ECD) calculations. Nearly all compounds were evaluated for their anti-inflammatory activities in RAW264.7 cells. Compounds 1 and 7–11 displayed significant anti-inflammatory activities with IC50 values ranging from 3.71 to 32.04 μM.

Mechanistic Details of Asymmetric Bromocyclization with BINAP Monoxide: Identification of Chiral Proton-Bridged Bisphosphine Oxide Complex and Its Application to Parallel Kinetic Resolution.

The mechanism of our previously reported catalytic asymmetric bromocyclization reactions using 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) monoxide was examined in detail by the means of control experiments, NMR studies, X-ray structure analysis, and CryoSpray electrospray ionization mass spectrometry (ESI-MS) analysis. The chiral BINAP monoxide was transformed to a key catalyst precursor, proton-bridged bisphosphine oxide complex (POHOP·Br), in the presence of N-bromosuccinimide (NBS) and contaminating water. The thus-formed POHOP further reacts with NBS to afford BINAP dioxide and molecular bromine (Br2) simultaneously in equimolar amounts. While the resulting Br2 is activated by NBS to form a more reactive brominating reagent (Br2─NBS), BINAP dioxide serves as a bifunctional catalyst, acting as both a Lewis base that reacts with Br2─NBS to form a chiral brominating agent (P═O+─Br) and also as a Brønsted base for the activation of the substrate. By taking advantage of this novel concerted Lewis/Brønsted base catalysis by BINAP dioxide, we achieved the first regio- and chemodivergent parallel kinetic resolutions (PKRs) of racemic unsymmetrical bisallylic amides via bromocyclization.

Polyketide Derivatives from the Endophytic Fungus Phaeosphaeria sp. LF5 Isolated from Huperzia serrata and Their Acetylcholinesterase Inhibitory Activities.

The secondary metabolites of Phaeosphaeria sp. LF5, an endophytic fungus with acetylcholinesterase (AChE) inhibitory activity isolated from Huperzia serrata, were investigated. Their structures and absolute configurations were elucidated by means of extensive spectroscopic data, including one- and two-dimensional nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) analyses, and calculations of electronic circular dichroism (ECD). A chemical study on the solid-cultured fungus LF5 resulted in 11 polyketide derivatives, which included three previously undescribed derivatives: aspilactonol I (4), 2-(1-hydroxyethyl)-6-methylisonicotinic acid (7), and 6,8-dihydroxy-3-(1′R, 2′R-dihydroxypropyl)-isocoumarin (9), and two new natural-source-derived aspilactonols (G, H) (2, 3). Moreover, the absolute configuration of de-O-methyldiaporthin (11) was identified for the first time. Compounds 4 and 11 exhibited inhibitory activity against AChE with half maximal inhibitory concentration (IC50) values of 6.26 and 21.18 µM, respectively. Aspilactonol I (4) is the first reported furanone AChE inhibitor (AChEI). The results indicated that Phaeosphaeria is a good source of polyketide derivatives. This study identified intriguing lead compounds for further research and development of new AChEIs.

Cuprous‐based composite ionic liquids for the selective absorption of CO: Experimental study and thermodynamic analysis

AbstractThree cuprous‐based composite ionic liquids (ILs) [EimH][OAc]–xCuOAc (x = 0.5, 0.6, 0.7) were prepared and employed for efficient absorption of CO. It is shown that the cuprous composite IL [EimH][OAc]–0.6CuOAc exhibited the largest absorption capacity for CO (0.031 g/g at 293.15 K and 1 bar) and had a record CO/N2 selectivity of 967, which is better than most of common ILs and solvents reported in the literature. The results of Fourier transform infrared (FTIR) spectra, electrospray ionization mass spectrometry (ESI‐MS) analysis, and theoretical calculations reveal that such superior CO capacity mainly resulted from two kinds of chemical interaction between CO and the active anionic species [Cu(OAc)2]− in [EimH][OAc]–0.6CuOAc. Furthermore, a “deactivated IL model” was further proposed to accurately describe the absorption behavior of CO in [EimH][OAc]–0.6CuOAc, in which the thermodynamic parameters including Henry's law constants, reaction equilibrium constants, and absorption enthalpies were estimated by the correlation of the experimental solubilities of CO.

Isolation of the Novel Strain Bacillus amyloliquefaciens F9 and Identification of Lipopeptide Extract Components Responsible for Activity against Xanthomonas citri subsp. citri.

Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a quarantine disease that seriously affects citrus production worldwide. The use of microorganisms and their products for biological control has been proven to be effective in controlling Xanthomonas disease. In this study, a novel Xcc antagonistic strain was isolated and identified as Bacillus amyloliquefaciens F9 by morphological and molecular analysis. The lipopeptide extract of B. amyloliquefaciens F9 (F9LE) effectively inhibited the growth of Xcc in an agar diffusion assay and restrained the occurrence of canker lesions in a pathogenicity test under greenhouse conditions. Consistent with these findings, F9LE treatment significantly inhibited the production of extracellular enzymes in Xcc cells and induced cell wall damage, with leakage of bacterial contents revealed by scanning electron microscopy and transmission electron microscopy analyses. In addition, F9LE also showed strong antagonistic activity against a wide spectrum of plant pathogenic bacteria and fungi. Furthermore, using electrospray ionization mass spectrometry analysis, the main antimicrobial compounds of strain F9 were identified as three kinds of lipopeptides, including homologues of surfactin, fengycin, and iturin. Taken together, our results show that B. amyloliquefaciens F9 and its lipopeptide components have the potential to be used as biocontrol agents against Xcc, and other plant pathogenic bacteria and fungi.

Conjugation of the glutelin hydrolysates-glucosamine by transglutaminase and functional properties and antioxidant activity of the products

A novel mixture of glycopeptides was prepared from corn glutelin and glucosamine (GlcN). The functional properties and antioxidative activities of this mixture were investigated. Corn glutelin was limited hydrolyzed by Alcalase, and then its hydrolysates were glycosylated with GlcN by transglutaminase (TGase) to modify its main and side chain, respectively. Under the optimized conditions, the content of GlcN conjugated to peptides was 81.98 ± 1.98 mg/g glutelin peptides. According to electrospray ionization mass spectrometry (ESI-MS) analysis, there are two types of glycopeptides in the mixture, TGase and non-enzymatic glycated counterparts. Compared with original glutelin, the glycosylated glutelin hydrolysates exhibited better solubility in the pH range of 2–11 and other functional properties except foaming stability. Meanwhile, it is more easily digested by pepsin and trypsin, and possessed excellent antioxidative activities. It also exhibited cytoprotective effects and intracellular ROS scavenging activities in LO2 cells subjected to oxidative stress by oxidation with ethanol solution.

Neuroprotective effects of a new triterpenoid from edible mushroom on oxidative stress and apoptosis through the BDNF/TrkB/ERK/CREB and Nrf2 signaling pathway in vitro and in vivo.

Inonotus obliquus (Fr.) Pilat is an edible mushroom which is used to produce tea and syrup due to its medicinal properties. In this study, 10 secondary metabolites (1-10), including a new lanostane triterpenoid named 2α-hydroxy-inotodiol (2α-HI, 1), were identified from the edible mushroom I. obliquus through high-resolution electrospray ionization mass spectrometry (HRESIMS) and nuclear magnetic resonance spectroscopy (NMR) data analysis. The neuroprotective function of all steroidal metabolites in H2O2-induced SH-SY5Y cells was investigated. The results showed that 2α-HI exhibited the most remarkable neuroprotective activity. In the meantime, 2α-HI significantly ameliorated oxidative stress damage, reactive oxygen species (ROS) accumulation and mitochondrial damage induced by H2O2 in SH-SY5Y cells. The Nrf2 siRNA and inhibitors transfected the SH-SY5Y cells, indicating the Nrf2 and BDNF/TrkB/ERK/CREB pathway mediated the neuroprotective effects of 2α-HI against the H2O2-stimulated oxidative stress and apoptosis. Moreover, the neuroprotection of 2α-HI was preliminarily verified in zebrafish. In conclusion, this research was the first to confirm that 2α-HI could effectively protect SH-SY5Y cells against H2O2-induced oxidative stress and apoptosis via the Nrf2 and BDNF/TrkB/ERK/CREB signaling pathway. Hence, this mushroom could be a potential dietary supplement to ameliorate neurodegenerative diseases.

Effects of Fengycins and Iturins on Fusarium oxysporum f. sp. physali and Root Colonization by Bacillus velezensis Bs006 Protect Golden Berry Against Vascular Wilt.

Bacillus velezensis Bs006 has shown antagonistic activity on Fusarium oxysporum f. sp. physali and biocontrol activity against Fusarium wilt (FW) in golden berry (Physalis peruviana). We hypothesized that strain Bs006 has the ability to synthesize antimicrobial cyclic lipopeptides (CLPs) like other members of the same species. However, if so, the real effects of CLPs on F. oxysporum f. sp. physali and their potential as a biocontrol tool against Physalis-FW have not been elucidated. In this study the CLPs profile of Bs006 in liquid culture and antagonist-plant-pathogen interactions were characterized. Also, the potential effects of supernatant free of bacteria against F. oxysporum f. sp. physali and FW were explored and compared with the effects of pure CLPs. Ultraperformance liquid chromatography-electrospray ionization-mass spectrometry analysis revealed the capacity of Bs006 to synthesize homologous compounds of iturins, surfactins, and fengycins in liquid culture and on the inhibition zone against F. oxysporum f. sp. physali in dual confrontation tests. Bs006 supernatant reduced the germination and growth of F. oxysporum f. sp. physali and caused vacuolization, swelling, and lysis of F. oxysporum f. sp. physali cells in a concentration-dependent manner. Pure fengycins affected the development of F. oxysporum f. sp. physali from 11 mg/liter and iturins from 21 mg/liter. In a gnotobiotic system, Bs006 colonized the root surface of golden berry, inhibited the growth of F. oxysporum f. sp. physali, and produced CLPs. Individual application of Bs006 and supernatant protected the plants from F. oxysporum f. sp. physali infections by 37 to 53%, respectively. Meanwhile, fengycins reduced the disease progress by 39%. These results suggest further studies to select an optimum combination of Bs006 and supernatant or CLPs, which might be a good option as biofungicide against F. oxysporum f. sp. physali.

Molecular differentiation of Panax notoginseng grown under different conditions by internal extractive electrospray ionization mass spectrometry and multivariate analysis

Panax notoginseng is a highly valuable and widely used herb in traditional Chinese medicine. The quality and efficacy of Panax notoginseng grown under different conditions can greatly vary due to the differences in chemical composition. The analysis of chemical composition in Panax notoginseng typically involves various experimental steps including extraction, chromatographic separation and characterization, which can be time- and labor-consuming. Therefore, the efficient quality assessment and control of Panax notoginseng requires the development of more rapid methods for the chemical characterization and classification of Panax notoginseng. In this study, a method based on internal extractive electrospray ionization mass spectrometry (iEESI-MS) was developed to characterize chemical components of Panax notoginseng samples under different growth conditions (e.g., place of origin, soil quality, growth season) at the speed of 0.5 min per sample, without sample pretreatment and chromatographic separation. A total of 35 chemical components, including sugars, saponins, organic acids, etc., were identified in Panax notoginseng samples. Clear separation was observed in the multivariate analysis of the iEESI-MS data from Panax notoginseng samples grown under different conditions. The difference in the content of sucrose, fructose, Rg1, Rf, Rb1, Noto-R1, malonyl-Rb1, malonyl-Rg1, malonyl-Rf, Rd, Re, linoleic acid, palmitic acid and malic acid can be used as key characteristic indicators to discriminate origin, commercial specifications, and cultivation conditions of Panax notoginseng samples. The results of our study indicate the high power of iEESI-MS for the rapid molecular characterization and classification of Panax notoginseng under different growth conditions, which can be used for the quality assessment of traditional herbal medicines as well as in pharmaceutical and clinical analysis.

Recycling of residual valuable metals in cyanide-leached gold wastewater using the N263-TBP system

In this study, the synergistic extraction system of trioctylmethyl ammonium chloride (N263)-tributyl phosphate (TBP)-n-octanol-sulfonated kerosene was used to enrich and recover valuable metals from cyanide gold extraction of wastewater. The effects of the proportion of N263 and TBP, contact time, initial pH of water phase, temperature, and phase ratio (O/A) on the extraction percentage of metal cyanide complex ions and the synergistic extraction reaction mechanism were mainly investigated. Results showed that the single-stage extraction percentages of Cu, Zn, and Fe ions in wastewater were 99.87%, 99.8%, and 96.2%, respectively, and the saturated extraction capacity was 4356.4 mg/L under the conditions of N263 (20 vol%)-TBP (20 vol%)-n-octanol (10 vol%)-sulfonated kerosene system at 25 °C, O/A of 1:1, pH of 10, and contact time of 5 min. Fourier transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectrometry (ESI-MS) analyses showed that metals entered the organic phase in the form of metal cyanide complex ions during extraction. Metal cyanide complex ions preferentially combined with TBP to lose hydrophilicity and then reacted with N263 cations to enter the organic phase. The saturated organic phase was stripped by NaOH and NaSCN mixed solution, and the total concentration of metal ions in the stripping solution reached 11,996.6 mg/L.

Improved coverage of plant metabolites using powder laser desorption/ionization coupled with Fourier-transform ion cyclotron mass spectrometry

In this study, the effectiveness of powder laser desorption/ionization (LDI) coupled with Fourier-transform ion cyclotron mass spectrometry (FT-ICR MS) was evaluated for the improved coverage of plant metabolites. Ground plant (powder) was fixed on a metal plate using double-sided tape. Compared with the conventional approach involving liquid extraction, which is followed by electrospray ionization MS analysis, a smaller amount of sample (∼200 µg) was required in the proposed method. Additionally, the laborious steps of liquid extraction, concentration, and solid-phase extraction were avoided. Employing the proposed method in Centella asiatica leaves analysis, higher number of reproducible molecular formulas (>5000) and metabolites (>650) were obtained than the conventional methods. Flavonoids, phenolic acids, xanthones, lipids, carbohydrates, terpenoids, and alkaloids compounds were detected from leaves, stems, and roots of C. asiatica. This study indicates that LDI FT-ICR MS is a quick and effective tool for enhanced plant metabolite profiling in the solid phase.

Liquid chromatography coupled to Venturi easy ambient sonic spray ionization mass spectrometry

Venturi easy ambient sonic spray ionization (V-EASI) is a soft ambient ionization (AI) source that has the advantages of being suitable to the analysis of samples in solution (differently from the majority of AI sources), performing self-pumping, voltage- and heat-free ionization, and requiring minimum or no sample preparation. Since this ionization technique has not been fully explored, the present study provides a proof of principle of the coupling of liquid chromatography to mass spectrometry (LC-MS) using V-EASI as the interface. In order to test the performance of the developed LC-V-EASI-MS system, a quantification method for bixin, a natural dye from annatto (Bixa Orellana L.), which is known to be sensitive to the high voltage applied for electrospray ionization mass spectrometry (ESI-MS) analysis, was validated according to FDA criteria and tested in real samples. The analytical method was successfully applied and met the validation criteria, providing a detectability 10 times better than methods already reported to the quantification of bixin and no matrix effect was observed. Therefore, this proof of principle contributes to the continuous development of AI sources that represents the last great technological advance in MS towards becoming a miniaturized technique able to analyze samples closer to their actual state.

Rapid authenticity assessment of Brazilian palm kernel oils by mass spectrometry combined with chemometrics

Adulteration became a serious problem to food industries as it steadily spread across the globe in the past decades, affecting several food products, but especially vegetable oils. Palm kernel oil is a highly susceptible target for adulteration due to its exceptional characteristics and several applications. Hence, this study utilized gas chromatography with flame ionization detector, and direct infusion electrospray ionization mass spectrometry combined with chemometrics to assess the authenticity of seven Brazilian brands of palm kernel oil. Results indicated adulteration with at least 30% in all brands evaluated. Furthermore, presence of a different additive was verified for PKO1, PKO5, and PKO7. Thus, the association of direct infusion electrospray ionization mass spectrometry analysis with pattern recognition methods proved to be an attractive candidate for fast routine analyses to identify adulteration in industries.

Synthesis and pharmacological evaluation of novel naphthoquinone derivatives containing 1,2,4-triazine and 1,2,4-triazole moieties of methylene blue on the surface of a "core–shell" type catalyst for the Fenton system

Novel naphthoquinone derivatives bearing 1,2,4-triazine- (4a–b) and 1,2,4-triazole (5a–e) pharmacophores have been synthesized; their structure was confirmed by electrospray ionization mass spectrometry, 1H NMR, 13C NMR, IR spectroscopies and elemental analysis. The obtained heterocyclic compounds were estimated for their anticonvulsant activity on models of chemical- and electrical-induced seizures in pentylenetetrazole (PTZ) and maximal electroshock (MES) tests, respectively. Forced swimming test was used to evaluate the antidepressant effect of the naphthoquinone derivatives under study. Compounds 4a–b and 5a–e (100 mg kg–1) demonstrated anticonvulsant action comparable with valproic acid in PTZ-test and prevented the death of 100% of mice in MES model at 3 h and 24 h after oral administration. Moreover, these derivatives showed prolonged antidepressant-like properties, significantly reducing the duration of immobility time in comparison with the reference drug amitriptyline.

Microsampling with a Solid-Phase Extraction Cartridge: Storage and Online Mass Spectrometry Analysis.

This study aims to introduce the concept of utilizing a solid-phase extraction (SPE) cartridge for remote biofluid collection, followed by direct sample analysis at a later time. For this, a dried matrix spot was prepared in a syringe, in the form of SPE cartridge for the first time to enable small biofluid collection (microsampling), storage, shipment, and online electrospray ionization (ESI) mass spectrometry (MS) analysis of the stored dried samples. The SPE sorbents were packed into an ESI syringe and the resultant cartridge was used for sampling small volumes (<20 μL) of different complex biological fluids including blood, plasma, serum, and urine. The collected sample was stored in the dry state within the confinement of the SPE sorbent at room temperature, and analyte stability (e.g., diazepam) was maintained for more than a year. Direct coupling of the SPE cartridge to MS provides excellent accuracy, precision, and sensitivity for analyzing illicit drugs present in the biofluid. The corresponding mechanism of wrong-way positive ion generation from highly basic elution solvents was explored. Without chromatography, our direct SPE-ESI-MS analysis technique afforded detection limits as low as 26 and 140 pg/mL for raw urine and untreated plasma, respectively. These promising results proved that the new syringe-based SPE cartridge can serve as a good alternative to conventional microsampling techniques in terms of analyte stability, ease of operation and versatility, and analytical sensitivity and speed.

A Non-Covalent Dimer Formation of Quaternary Ammonium Cation with Unusual Charge Neutralization in Electrospray-Ionization Mass Spectrometry

Specific and nonspecific non-covalent molecular association of biomolecules is characteristic for electrospray-ionization mass spectrometry analysis of biomolecules. Understanding the interaction between two associated molecules is of significance not only from the biological point of view but also gas phase analysis by mass spectrometry. Here we reported a formation of non-covalent dimer of quaternary ammonium denatonium cation with +1 charge detected in the positive ion mode electrospray ionization mass spectrometry analysis of denatonium benzoate. Hydrogen deuterium exchange of amide and carbon-bonded hydrogens revealed that charge neutralization of one denatonium cation is the consequence of amide hydrogen dissociation. DFT (Density Functional Theory) calculations proved high thermodynamic stable of formed dimer stabilized by the short and strong N..H-N hydrogen bond. The signal intensity of the peak characterizing non-covalent dimer is low intensity and does not depend on the sample concentration. Additionally, dimer observation was found to be instrument-dependent. The current investigation is the first experimental and theoretical study on the quaternary ammonium ions dimer. Thus the present study has great significance for understanding the structures of the biomolecules as well as materials.

Characterization and Identification of Bioactive Polyphenols in the Trapabispinosa Roxb. Pericarp Extract.

In this study, we present the isolation and characterization of the structure of six gallotannins (1–6), three ellagitannins (7–9), a neolignan glucoside (10), and three related polyphenolic compounds (gallic acid, 11 and 12) from Trapa bispinosa Roxb. pericarp extract (TBE). Among the isolates, the structure of compound 10 possessing a previously unclear absolute configuration was unambiguously determined through nuclear magnetic resonance and circular dichroism analyses. The α-glucosidase activity and glycation inhibitory effects of the isolates were evaluated. Decarboxylated rugosin A (8) showed an α-glucosidase inhibitory activity, while hydrolyzable tannins revealed stronger antiglycation activity than that of the positive control. Furthermore, the identification and quantification of the TBE polyphenols were investigated by high-performance liquid chromatography coupled to ultraviolet detection and electrospray ionization mass spectrometry analysis, indicating the predominance of gallic acid, ellagic acid, and galloyl glucoses showing marked antiglycation properties. These findings suggest that there is a potential food industry application of polyphenols in TBE as a functional food with antidiabetic and antiglycation activities.