Electrospray Ionization Mass Spectrometry Analysis Research Articles

Turn-on detection of Al3+ ions using quinoline-based tripodal probe: mechanistic investigation and live cell imaging applications.

In this study, an easily synthesizable Schiff base probe TQSB having a quinoline fluorophore is demonstrated as a fluorescent and colorimetric turn-on sensor for Al3+ ions in a semi-aqueous medium (CH3CN/water; 4 : 1; v/v). Absorption, emission and colorimetric studies clearly indicated that TQSB exhibited a high selectivity toward Al3+, as observed from its excellent binding constant (Kb = 3.8 × 106 M-1) and detection limit (7.0 nM) values. TQSB alone was almost non-fluorescent in nature; however, addition of Al3+ induced intense fluorescence at 414 nm most probably due to combined CHEF (chelation-enhanced fluorescence) and restricted PET effects. The sensing mechanism was established via Job's plot, NMR spectroscopy, ESI-mass spectrometry, and density functional theory (DFT) analyses. Furthermore, to evaluate the applied potential of probe TQSB, its sensing ability was studied in real samples such as soil samples and Al3+-containing Digene gastric tablets as well as on low-cost filter paper strips. Fluorescence microscopy imaging experiments further revealed that TQSB can be used as an effective probe to detect intracellular Al3+ in live cells with no cytotoxicity.

Structural confirmation of position isomers 2‐(2‐methylaminoprolyl)benzofuran and 5‐(2‐methylaminopropyl)benzofuran: a combined mass spectrometric and computational study

AbstractRationalePhenylethylamines are one of the most common types of new psychoactive substances, following synthetic cannabinoids and synthetic cathinones. They are regulated in many countries because of their strong hallucinogenic effects, which can cause serious nerve damage. There is a wide variety of phenylethylamines, exhibiting rapid renewal and extremely similar structures, therefore accurate qualitative analysis of isomers is a difficult problem in current drug analysis.MethodsThe dissociation pathways of the position isomers 2‐(2‐methylaminoprolyl)benzofuran (2‐MAPB) and 5‐(2‐methylaminopropyl)benzofuran (5‐MAPB) were investigated by gas chromatography–mass spectrometry and liquid chromatography coupled to high‐resolution quadrupole Orbitrap MS. The dissociation patterns of the phenethylamine‐based designer drugs 2‐MAPB and 5‐MAPB were explored and extended in this work based on MS combined with density functional theory studies.ResultsFor electron ionization mass spectrometry (EI‐MS) analysis, the dissociation patterns of 2‐MAPB were similar to those of 5‐MAPB. For electrospray ionization mass spectrometry (ESI‐MSn) analysis, the hydrogen atom on amino group was facile to form a intramolecular hydrogen bond with the oxygen atom on the parent nucleus of benzofuran in the structure of 2‐MAPB, leading to higher abundance of the product ion at m/z 58. However, there was a conjugated system between the positive charge formed by the cleavage of the 5‐MAPB side chain and the benzofuran ring, enabling the 5‐MAPB to generate a product ion at m/z 131. Computational study showed that energy barrier and spin density difference distribution jointly control the selective dissociation in EI‐MS, while different types of orbital interaction induced by intramolecular hydrogen bond led to different dissociation results in ESI‐MSn.ConclusionsThese different dissociation patterns could be used to distinguish 2‐MAPB from 5‐MAPB. This could assist forensic laboratories in the differentiation and characterization of potential isomers in these kinds of compounds, especially in mixtures.

Synthesis, structural characterization, and DNA binding/cleavage studies of diorganotin(IV) carboxylates and their complexes with 1,10-phenanthroline: X-ray structures of [Me8Sn4(p-FC6H4CO2)4O2], [Bu2Sn(p-NO2C6H4CO2)2.phen], and DFT studies

The present study is focused on the mode of DNA-interactions with diorganotin(IV) carboxylates and their 1,10-phenanthroline (phen) complexes, and revealed that the planarity and extended π system of phen may increase the probability of DNA intercalation. Diorganotin(IV) derivatives of p-fluoro-/p-hydroxy-/p-nitro benzoic acid, viz. Bu2Sn(p-XC6H4CO2)2: X = F (1), OH (2), NO2 (3), Oct2Sn(p-NO2C6H4CO2)2 (4), and Me8Sn4(p-FC6H4CO2)4O2 (5), and their complexes with phen viz. Bu2Sn(p-XC6H4CO2)2.phen: X = F (6), OH (7), NO2 (8), Oct2Sn(p-NO2C6H4CO2)2.phen (9), and Me2Sn(p-FC6H4CO2)2.phen (10) have been synthesized and characterized by using various techniques including single crystal X-ray diffraction studies, nuclear magnetic resonance (1H, 13C, and 119Sn NMR), electrospray ionization mass spectrometry (ESI-MS), infrared (FT-IR), and elemental analysis. Based on crystal data, complexes (5) and (8) have a P-1 space group with a triclinic crystal system. In the octahedral geometry of complex (5), Sn atom has a tetranuclear Sn4O2 core, whereas complex (8) has a pentagonal bipyramidal geometry around Sn atom. The LanL2Z basis set has been employed for optimized gas-phase geometries, and the calculated ∠C-Sn-C bond angles agree with those obtained from NMR/X-ray studies. UV-visible, fluorescence and circular dichroism (CD) titrations showed interaction with Calf Thymus DNA (CT-DNA), and Kb and KSV values in the order of 103–105 M−1 indicate intercalation within the base pairs or in minor groove. Further, gel electrophoreses studies indicate that all of the complexes have efficiently cleaved plasmid pBR322 DNA into three bands; supercoiled, nicked/circular along with linear structure. The intriguing biophysical results suggest that these complexes may have anticancer potential.

A Direct Dilute-and-Shoot HPLC-MS/MS Method for Tetrahydrocannabinol (THC) Metabolites.

The Cannabis plant has been smoked for medicinal and recreational purposes for thousands of years. Tetrahydrocannabinol (THC) is the most well-known psychoactive cannabinoid, and the properties of other cannabinoids are becoming better understood. Due to increased exposure, hospitals and clinics will need access to rapid and accurate THC testing procedures to better inform patients and improve care. A rapid and reliable HPLC-MS/MS method was developed for the quantitative assessment of two THC metabolites (THC-COOH and THC-COO(Gluc)). The chromatographic separation was done using a short (50×4.6mm) phenyl-hexyl column with positive ESI mass spectrometry analysis. To reduce interferences and improve quantitation, the assay was run using multiple reaction monitoring mode. The method was shown to be precise (<15% CV with-in day & between day), accurate (±20%) and linear (>R2 0.99) within the range of 25-8000ng/mL.

Aggregation-Induced Emission via the Restriction of the Intramolecular Vibration Mechanism of Pinacol Lanthanide Complexes.

Pinacol lanthanide complexes PyraLn (Ln = Dy and Tb) with the restriction of intramolecular vibration were obtained for the first time via an in situ solvothermal coordination-catalyzed tandem reaction using cheap and simple starting materials, thereby avoiding complex, time-consuming, and expensive conventional organic synthesis strategies. A high-resolution electrospray ionization mass spectrometry (HRESI-MS) analysis confirmed the stability of PyraLn in an organic solution. The formation process of PyraLn was monitored in detail using time-dependent HRESI-MS, which allowed for proposing a mechanism for the formation of pinacol complexes via in situ tandem reactions under one-pot coordination-catalyzed conditions. The PyraLn complexes constructed using a pinacol ligand with a butterfly configuration exhibited distinct aggregation-induced emission (AIE) behavior, with the αAIE value as high as 60.42 according to the AIE titration curve. In addition, the PyraLn complexes in the aggregated state exhibit a rapid photoresponse to various 3d metal ions with low detection limits. These findings provide fast, facile, and high-yield access to dynamic, smart lanthanide complex emissions with bright emission and facilitate the rational construction of molecular machines for artificial intelligence.

Nutritionally enriched tomatoes (Solanum lycopersicum L.) grown with wood distillate: chemical and biological characterization for quality assessment.

Bio-based products are nowadays useful tools able to affect the productivity and quality of conventionally cultivated crops. Several bio-based products are currently on the market; one of the newest and most promising is the wood distillate (WD) derived from the pyrolysis process of waste biomass after timber. Its foliar application has been widely investigated and shown to promote the antioxidant profile of cultivated crops. WD was used here as additive for the cultivation of tomato (Solanum lycopersicum L.) plants. The application improved quality (chemical) parameters, minerals, polyphenols, and lycopene contents of tomato fruits. The extracts of WD-treated and untreated tomatoes have been chemically and biologically characterized. The 1 H-NMR and ESI-mass spectrometry analyses of the extracts revealed the presence of different fatty acids, amino acids and sugars. In particular, the WD-treated tomatoes showed the presence of pyroglutamic acid and phloridzin derivatives, but also dihydrokaempferol, naringenin glucoside, cinnamic acid, and kaempferol-3-O-glucoside. When tested in cells, the extracts showed a promising anti-inflammatory profile in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Furthermore, the extracts displayed a slight vasorelaxant activity on rat aorta rings (either endothelium-denuded or endothelium-intact) pre-contracted with phenylephrine or potassium chloride. PRACTICAL APPLICATION: Wood distillate has been used for tomato plant growth. Tomatoes showed improved nutritional parameters, and their extracts displayed antioxidant and anti-inflammatory activities.

Synergistic antifungal activity and potential mechanism of action of a glycolipid like compound produced by Streptomyces blastmyceticus S108 against Candida clinical isolates.

The present study aimed to investigate a novel antifungal compound produced by Streptomyces blastmyceticus S108 strain. Its effectiveness against clinical isolates of Candida species and its synergistic effect with conventional antifungal drugs were assessed and its molecular mechanism of action was further studied against C. albicans. A newly isolated strain from Tunisian soil, Streptomyces blastmyceticus S108, showed significant antifungal activity against Candida species by well diffusion method. The butanolic extract of S108 strain supernatant exhibited the best anti-Candida activity with a minimal inhibitory concentration (MIC) value of 250 μg mL-1, determined by the microdilution method. The bio-guided purification steps of the butanolic extract were performed by chromatographic techniques. Among the fractions obtained, F13 demonstrated the highest level of activity, displaying a MIC of 31.25 μg mL-1. Gas Chromatography-Mass Spectrometry (GC-MS) and Electrospray Ionisation Mass Spectrometry (ESI-MS) analyses of this fraction (F13) revealed the glycolipidic nature of the active molecule with a molecular weight of 685.6 m/z. This antifungal metabolite remained stable to physicochemical changes and did not show hemolytic activity even at 4 MIC corresponding to 125 µg mL-1 towards human erythrocytes. Besides, the glycolipid compound was combined with 5-flucytosine and showed a high synergistic effect with a FICI value 0.14 against C. albicans ATCC 10231. This combination resulted in a decrease of MIC values of 5-flucytosine and the glycolipid-like compound by 8 and 64-fold, respectively. The examination of gene expression in treated Candida albicans cells by qPCR revealed that the active compound tested alone or in combination with 5-flucytosine blocks the ergosterol biosynthesis pathway by down regulating the expression of ERG1, ERG3, ERG5, ERG11 and ERG25 genes. The new glycolipid like compound, produced by Streptomyces S108 isolate, could be a promising drug for medical use against pathogenic Candida isolates.

Development of citric acid grafted graphene oxide nanosheets as nanocatalyst in the synthesis of an imidazole derivative

Herein, we report the fabrication of graphite oxide (GO) nanosheets using the modified Hummer’s method. The prepared GO nanosheets were anchored with citrate functionality to develop a new nanocatalyst for potential organic conversions. The prepared native, as well as functionalized nanostructures, were characterized using advanced analytical techniques. The citrate functionalized GO nanosheets were then used as a nanocatalyst for the organic synthesis of an imidazole derivative through an aldehyde-amine condensation route. The hence produced imidazole derivative was elucidated using electrospray ionization mass spectrometry and thermogravimetric analysis. The nanocatalyst showed good catalytic activity and reusability for an aldol condensation reaction. We suggest that the prepared nanocatalyst could further be investigated for other condensation reactions.

Bidesmosidic and monodesmosidic triterpenoid saponins from the grain of Amaranthus hypochondriacus

Five known bidesmosidic triterpenoid saponins (1–5) and their hydrolysates, namely two new monodesmosidic triterpenoid saponins (1′ and 2′) and three known saponins (3′–5′), were isolated from Amaranthus hypochondriacus seeds. The structures of the new compounds were determined using interpreting 1D and 2D nuclear magnetic resonance (NMR) data and high-resolution electrospray ionisation mass spectrometry (HRESI-MS) analyses as 3-O-β-D-glucuronopyranosyl-30-normedicagenic acid (1′) and 3-O-[α-L-rhamnopyranosyl (1 → 3)-β-D-glucuronopyranosyl] bayogenin (2′). For the first time, 5 and 5′ were isolated from Medicago plants as the first examples of glycosides in medicagenic acid from Amaranthus plants. While bidesmosidic saponins showed no cytotoxicity, monodesmosidic saponins, except for 1′, showed moderate cytotoxicity against human cervix adenocarcinoma (HeLa) cells. In addition, monodesmosidic saponins showed anti-fungal activity against the rice blast fungus (Pyricularia oryzae).

Ruthenium arene complexes with chalcone ligands incorporating pyridyl and anthryl units: Synthesis, aqueous stability and interaction with quadruplex DNA

Twelve ruthenium(II) arene complexes incorporating chalcone ligands with pyridyl and anthryl units, as well as chlorido or oxalato ancillary ligands, have been synthesized and structurally characterized by 1H NMR spectroscopy, ESI mass spectrometry and elemental analysis. Compared to the oxalato compounds, the chlorido complexes were less stable and more susceptible to aquation in solution; the dissociation was suppressed in the presence of chloride ions. All six of the chlorido complexes and three of the oxalato complexes were able to bind to quadruplex DNA, exhibiting greater selectivity for HTelo over c-myc. The cationic species 3f, in which the chalcone chelates to the metal center, was found to bind to HTelo most strongly. These results indicate that the ancillary ligand, the location of the N-donor atom in the pyridyl ring, the position of the α,β-unsaturated ketone relative to the pyridyl and anthryl entities in the chalcone moiety, as well as the presence of the metal center all play significant roles in improving the binding of such complexes to quadruplex DNA.

Direct Analysis of Micro-biopsy Samples by Polarity Gradient Focusing Dip-and-Go Mass Spectrometry.

Direct analysis of micro-biopsy samples by mass spectrometry at single-cell level still faces major challenges. In this work, we developed a polarity gradient focusing dip-and-go strategy (PGF-Dip&Go) during induced electrospray ionization mass spectrometry (iESI-MS) analysis for real-time enrichment and spatial separation of compounds such as lipids, alkaloids, fatty amines, and drugs. Compared with direct iESI-MS analysis, enrichment of analytes (enrichment factor of 5.0-100.0) and spatial separation between different analytes were achieved. Owing to the enrichment effect and salt cleanup effect, the sensitivity of PGF-Dip&Go has been improved by 25-10,000 times compared with direct iESI-MS. PGF-Dip&Go has been successfully applied for the analysis of lipids in a 200 pL micro-biopsy section from an individual fish egg. Lysophosphatidylcholine (LPC), phosphatidylcholine (PC), and triglyceride (TG) were significantly enriched and separated according to their polarity differences, proving the potential of PGF-Dip&Go to be a noninvasive and powerful analytical tool for in situ analysis of complex small volumes in the future.

Identification of glycine betaine as a host-derived molecule required for the vegetative proliferation of the protozoan parasite Perkinsus olseni.

Perkinsus olseni is an industrially significant protozoan parasite of Manila clam, Ruditapes philippinarum. So far, various media, based on Dulbecco's Modified Eagle Medium and Ham's F-12 nutrient mixture with supplementation of fetal bovine serum (FBS), have been developed to proliferate the parasitizing trophozoite stage of P. olseni. The present study showed that P. olseni did not proliferate in FBS-deficient Perkinsus broth medium (PBMΔF), but proliferated well in PBMΔF supplemented with tissue extract of host Manila clams, indicating that FBS and Manila clam tissue contained molecule(s) required for P. olseni proliferation. Preliminary characterization suggested that the host-derived molecule(s) was a heat-stable molecule(s) with a molecular weight of less than 3 kDa, and finally a single molecule required for the proliferation was purified by high-performance liquid chromatography processes. High-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analyses identified this molecule as glycine betaine (=trimethylglycine), and the requirement of this molecule for P. olsseni proliferation was confirmed by an assay using chemically synthesized, standard glycine betaine. Although glycine betaine was required for the proliferation of all examined Perkinsus species, supplementation of glycine betaine precursors, such as choline and betaine aldehyde, enhanced the proliferation of 4 Perkinsus species (P. marinus, P. chesapeaki, P. mediterraneus and P. honshuensis), but not of 2 others (P. olseni and P. beihaiensis). Thus, it was concluded that the ability to biosynthesise glycine betaine from its precursors varied among Perkinsus species, and that P. olseni and P. beihaiensis lack the ability required to biosynthesize glycine betaine for proliferation.

Tamarind Seed Polysaccharide Hydrolysate Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis via Regulating the Gut Microbiota.

(1) Background: Ulcerative colitis (UC) is a disease caused by noninfectious chronic inflammation characterized by varying degrees of inflammation affecting the colon or its entire mucosal surface. Current therapeutic strategies rely on the suppression of the immune response, which is effective, but can have detrimental effects. Recently, different plant polysaccharides and their degradation products have received increasing attention due to their prominent biological activities. The aim of this research was to evaluate the mitigation of inflammation exhibited by tamarind seed polysaccharide hydrolysate (TSPH) ingestion in colitis mice. (2) Methods: TSPH was obtained from the hydrolysis of tamarind seed polysaccharide (TSP) by trifluoroacetic acid (TFA). The structure and physical properties of TSPH were characterized by ultraviolet spectroscopy (UV), thin-layer chromatography (TLC), fourier transform infrared spectroscopy (FT-IR), and High-Performance Liquid Chromatography and Electrospray Ionization Mass Spectrometry (HPLC-ESI/MS) analysis. Then, the alleviative effects of the action of TSPH on 2.5% dextran sodium sulfate (DSS)-induced colitis mice were investigated. (3) Results: TSPH restored pathological lesions in the colon and inhibited the over-secretion of pro-inflammatory cytokines in UC mice. The relative expression level of mRNA for colonic tight junction proteins was increased. These findings suggested that TSPH could reduce inflammation in the colon. Additionally, the structure of the gut microbiota was also altered, with beneficial bacteria, including Prevotella and Blautia, significantly enriched by TSPH. Moreover, the richness of Blautia was positively correlated with acetic acid. (4) Conclusions: In conclusion, TSPH suppressed colonic inflammation, alleviated imbalances in the intestinal flora and regulated bacterial metabolites. Thus, this also implies that TSPH has the potential to be a functional food against colitis.

Limosilactobacillus reuterias sustainable biological control agent against toxigenic Fusarium verticillioides.

Corn contamination with Fusarium verticillioides (Sacc.) Nirenberg is a worldwide problem that affects yield and grain quality resulting in severe economic losses and implications for food safety. Control of F. verticillioides is a challenge, but lactic acid bacteria (LAB) has high potential as a biological control agent. In this study, the antifungal effect of Limosilactobacillus reuteri (formerly Lactobacillus reuteri) LR-92 against F. verticillioides 97L was investigated. Cell-free supernatant (CFS) from L. reuteri showed concentration-dependent fungicidal and fungistatic activity against F. verticillioides 97L. The antifungal compounds from CFS showed heat stability and pH dependence, and antifungal activity was not affected by treatment with proteolytic enzymes. High-performance liquid chromatography analysis indicated that L. reuteri LR-92 produces lactic and acetic acids. After liquid-liquid extraction, electrospray ionization mass spectrometry analysis of the active ethyl acetate fraction containing antifungal compounds revealed the production of 3-phenyllactic acid, cyclo-(L-Pro-L-Leu), cyclo-(L-Pro-L-Phe), and cyclo-(L-Phe-trans-4-OH-L-Pro). L. reuteri LR-92 has potential as a biocontrol agent for F. verticillioides and contributes to food safety.

Cycloartane Saponins from Astragalus glycyphyllos and Their In Vitro Neuroprotective, Antioxidant, and hMAO-B-Inhibiting Effects.

Astragalus glycyphyllos (Fabaceae) is used in the traditional medicine of many countries against hepatic and cardiac disorders. The plant contains mainly flavonoids and saponins. From a defatted methanol extract from its overground parts, a new triterpenoid saponin, 3-O-[α-L-rhamnopyranosyl-(1→2)]-β-D-xylopyranosyl]-24-O-α-L-arabinopyranosyl-3β,6α,16β,24(R),25-pentahydroxy-20R-cycloartane, together with the rare saponin astrachrysoside A, were isolated using various chromatography methods. The compounds were identified via extensive high resolution electrospray ionisation mass spectrometry (HRESIMS) and NMR analyses. Both saponins were examined for their possible antioxidant and neuroprotective activity in three different in vitro models. Rat brain synaptosomes, mitochondria, and microsomes were isolated via centrifugation using Percoll gradient. They were treated with the compounds in three different concentrations alone, and in combination with 6-hydroxydopamine or tert-butyl hydroperoxide as toxic agents. It was found that the compounds had statistically significant dose-dependent in vitro protective activity on the sub-cellular fractions. The compounds exhibited a weak inhibitory effect on the enzyme activity of human recombinant monoamine oxidase type B (hMAO-B), compared to selegiline.

Datura stramonium Flowers as a Potential Natural Resource of Bioactive Molecules: Identification of Anti-Inflammatory Agents and Molecular Docking Analysis.

The present study investigated the antioxidant, antibacterial, antiviral and anti-inflammatory activities of different aerial parts (flowers, leaves and seeds) of Datura stramonium. The plant material was extracted with 80% methanol for about 24 h. The sensitivity to microorganisms analysis was performed by the microdilution technique. Antioxidant tests were performed by scavenging the DPPH and ABTS radicals, and by FRAP assay. Anti-inflammatory activity was evaluated through the inhibition of nitric oxide production in activated macrophage RAW 264.7 cells. Cell viability was assessed with an MTT assay. Results show that the flower extract revealed a powerful antimicrobial capacity against Gram-positive bacteria and strong antioxidant and anti-inflammatory activities. No significant cytotoxicity to activated macrophages was recorded. High resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analysis identified two molecules with important anti-inflammatory effects: 12α-hydroxydaturametelin B and daturametelin B. Molecular docking analysis with both pro-inflammatory agents tumor necrosis factor alpha and interleukin-6 revealed that both compounds showed good binding features with the selected target proteins. Our results suggest that D. stramonium flower is a promising source of compounds with potential antioxidant, antibacterial, and anti-inflammatory activities. Isolated withanolide steroidal lactones from D. stramonium flower extract with promising anti-inflammatory activity have therapeutic potential against inflammatory disorders.

Anticancer Tungstenocenes with a Diverse Set of (O,O-), (O,S-) and (O,N-) Chelates-A Detailed Biological Study Using an Improved Evaluation via 3D Spheroid Models.

The synthesis, characterization and biological activity of tungstenocenes with varying biologically active (O,O-), (S,O-) and (N,O-) chelates are described. Complexes were characterized by 1H and 13C NMR, elemental analysis, ESI-mass spectrometry, FT-IR spectroscopy and X-ray diffraction analysis. The aqueous stability was studied by UV/Vis spectroscopy and the WIV to WV process by cyclic voltammetry. The cytotoxicity was determined by the MTT assay in A549, CH1/PA-1 and SW480 cancer cells as well as in IMR-90 human fibroblasts. Extensive biological evaluation was performed in three other human cancer cell lines (HCT116, HT29 and MCF-7) in monolayer and multicellular tumor spheroid cultures to better understand the mode of action. Lead compounds showed promising in vitro anticancer activity in all cancer cell lines. Further studies yielded important insights into apoptosis induction, ROS generation, different patterns in metal distribution (detected by LA-ICP-TOF-MS), changes in KI67 (proliferation marker) expression and DNA interactions. The results based on qualitative and quantitative research designs show that complexes containing (S,O-) chelates are more active than their (O,O-) and (N,O-) counterparts. The most striking results in spheroid models are the high antiproliferative capacity and the different distribution pattern of two complexes differing only in a W-S or W-O bond.

In Situ Spatial Analysis of Metabolic Heterogeneity in Single Living Tumor Spheroids Using Nanocapillary-Based Electrospray Ionization Mass Spectroscopy.

Spatial metabolomic analysis of individual tumor spheroids can help investigate metabolic rearrangements in different cellular regions of a spheroid. In this work, a nanocapillary-based electrospray ionization mass spectroscopy (ESI-MS) method is established that could realize the spatial sampling of cellular components in different regions of a single living tumor spheroid and the subsequent MS analysis for a metabolic study. During the penetration of the nanocapillary into the spheroid for sampling, this "wound surface" at the outer layer of the spheroid takes only 0.1% of the whole area that maximally maintains the cellular activity inside the spheroid for the metabolic analysis. Using the ESI-MS analysis, different metabolic activities in the inner and outer (upper and lower) layers of a single spheroid are revealed, giving a full investigation of the metabolic heterogeneity inside one living tumor spheroid for the first time. In addition, the metabolic activities between the outer layer of the spheroid and two-dimensional (2D)-cultured cells show obvious differences, which suggests more frequent cell-cell and cell-extracellular environment interactions during the culture of the spheroid. This observation not only establishes a powerful tool for the in situ spatial analysis of the metabolic heterogeneity in single living tumor spheroids but also provides molecular information to elucidate the metabolic heterogeneity in this three-dimensional (3D)-cultured cell model.

Combination of Internal Extractive Electrospray Ionization Mass Spectrometry and Statistical Analysis for High-Throughput Molecular Differentiation of Rehmannia glutinosa Samples.

Rehmannia glutinosa (Gaert.) Libosch. ex Fisch. et Mey. is a perennial herb of the Scrophulariaceae family, which has long enjoyed a good reputation in China, and has a wide range of pharmacological effects and clinical applications. The place of origin is an important factor affecting the chemical composition of R. glutinosa, resulting in different pharmacological effects. Herein, internal extractive electrospray ionization mass spectrometry (iEESI-MS) combined with statistical techniques was established for high-throughput molecular differentiation of different R. glutinosa samples. Dried and processed R. glutinosa samples from four different places of origin were analyzed by iEESI-MS with high throughput (>200 peaks) and rapidness (<2 min/sample) without sample pretreatment. Clear separation models created by OPLS-DA were then established for distinguishing the places of origin of dried and processed R. glutinosa by using the obtained MS data. In addition, the molecular differences between the pharmacological effects of dried and processed R. glutinosa were also investigated by OPLS-DA, and 31 different components were screened out. This work provides a promising method for evaluating the quality of traditional Chinese medicines and studying the biochemical mechanism of processing.

Identification of Loliolide with Anti-Aging Properties from Scenedesmus deserticola JD052.

Herein, different extracts of Scenedesmus deserticola JD052, a green microalga, were evaluated in vitro as a potential anti-aging bioagent. Although post-treatment of microalgal culture with either UV irradiation or high light illumination did not lead to a substantial difference in the effectiveness of microalgal extracts as a potential anti-UV agent, the results indicated the presence of a highly potent compound in ethyl acetate extract with more than 20% increase in the cellular viability of normal human dermal fibroblasts (nHDFs) compared with the negative control amended with DMSO. The subsequent fractionation of the ethyl acetate extract led to two bioactive fractions with high anti-UV property; one of the fractions was further separated down to a single compound. While electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy analysis identified this single compound as loliolide, its identification has been rarely reported in microalgae previously, prompting thorough systematic investigations into this novel compound for the nascent microalgal industry.