Development of a facile sensor for the determination of Brilliant Blue FCF in beverages

<div><p>A facile method was developed for the detection of Brilliant Blue FCF (BB FCF) (E133), a synthetic soluble colorant in common beverages. The method is based on a new composite of multi-walled carbon nanotube (MWCNT)-graphite oxide (GO)-room temperature ionic liquids (MWCNT/GO-RTIL) of 1-butyl-3-methylimidazolium hexafluorophosphate with high dispersibility and strong conductivity. Differential pulse stripping voltammetry (DPSV) and the MWCNT/GO-RTIL composite-modified glassy carbon electrode (GCE) were used to determine the BB FCF in this work. Under the optimum experimental conditions, the oxidation current of BB FCF was proportional to its concentration in two linear ranges, from 6.34 μg kg⁻¹ to 7.93 × 10² μg kg⁻¹ and 7.93 × 10² μg kg⁻¹ to 7.93 × 10³ μg kg⁻¹.</p><p>The detection limit was down to 3.01 μg kg⁻¹ at signal-to-noise ratio of 3. Also, this method has been successfully applied in the determination of BB FCF in common beverage samples, including RIO cocktail, Bacardi Breezer and Reinnbow rum dinks. The assay results of BB FCF in drink samples obtained by the proposed method were in a good agreement with the reference values detected by high performance liquid chromatography (HPLC). The proposed method provided a useful tool for the assay of BB FCF in drink samples.</p></div

Wide-Scope Screening of Illegal Adulterants in Dietary and Herbal Supplements via Rapid Polarity-Switching and Multistage Accurate Mass Confirmation Using an LC-IT/TOF Hybrid Instrument

A new analytical strategy was developed that integrates a generic sample preparation into a liquid chromatography–multistage ion trap/time-of-flight mass spectrometry (LC-IT­(MS^<i>n</i>)/TOF), allowing for large-scale screening and qualitative confirmation of wide-scope illegal adulterants in different food matrices. Samples were pretreated by a fast single-tube multifunction extraction for accurate multistage mass measurement on the hybrid LC-IT/TOF system. A qualitative validation performed for over 500 analyte–matrix pairs showed the method can reduce most of the matrix effects and achieve a lower limit of confirmation at 0.1 mg/kg for 73% of the target compounds. A unique combination of dual-polarity detection, retention time, isotopic profile, and accurate MS^<i>n</i> spectra enables more comprehensive and precise confirmation, based on the multiparameter matching by automated library searching against the user-created database. Finally, the applicability of this LC-IT­(MS^<i>n</i>)/TOF-based screening procedure for discriminating coeluting isobars, identifying nontarget adulterants, and even tentatively elucidating unexpected species in real samples is demonstrated

Synthesis and Biological Evaluation of Novel Gigantol Derivatives as Potential Agents in Prevention of Diabetic Cataract

<div><p>As a continuation of our efforts directed towards the development of natural anti-diabetic cataract agents, gigantol was isolated from Herba dendrobii and was found to inhibit both aldose reductase (AR) and inducible nitric oxide synthase (iNOS) activity, which play a significant role in the development and progression of diabetic cataracts. To improve its bioefficacy and facilitate use as a therapeutic agent, gigantol (compound <b>14f</b>) and a series of novel analogs were designed and synthesized. Analogs were formulated to have different substituents on the phenyl ring (compounds <b>4</b>, <b>5</b>, <b>8</b>, <b>14a-e</b>), substitute the phenyl ring with a larger steric hindrance ring (compounds <b>10</b>, <b>17c</b>) or modify the carbon chain (compounds <b>17a</b>, <b>17b</b>, <b>21</b>, <b>23</b>, <b>25</b>). All of the analogs were tested for their effect on AR and iNOS activities and on D-galactose-induced apoptosis in cultured human lens epithelial cells. Compounds <b>5</b>, <b>10</b>, <b>14a</b>, <b>14b</b>, <b>14d</b>, <b>14e</b>, <b>14f</b>, <b>17b</b>, <b>17c</b>, <b>23</b>, and <b>25</b> inhibited AR activity, with IC₅₀ values ranging from 5.02 to 288.8 μM. Compounds <b>5</b>, <b>10</b>, <b>14b</b>, and <b>14f</b> inhibited iNOS activity with IC₅₀ ranging from 432.6 to 1188.7 μM. Compounds <b>5</b>, <b>8</b>, <b>10</b>, <b>14b</b>, <b>14f</b>, and <b>17c</b> protected the cells from D-galactose induced apoptosis with viability ranging from 55.2 to 76.26%. Of gigantol and its analogs, compound <b>10</b> showed the greatest bioefficacy and is warranted to be developed as a therapeutic agent for diabetic cataracts.</p></div

Pharmacometabolomics in Endogenous Drugs: A New Approach for Predicting the Individualized Pharmacokinetics of Cholic Acid

The evaluation of individual variability in endogenous drugs’ metabolism and disposition is a very challenging task. We developed and validated a metabotype to pharmacokinetics (PK) matching approach by taking cholic acid as an example to predict the individualized PK of endogenous drugs. The stable isotope-labeled cholic acid was selected as the substitute analyte of cholic acid to ensure the accurate measurement of blood concentration. First, large-scale metabolite profiling studies were performed on the predose urine samples of 28 rats. Then, to examine the individualized PK of deuterium 4-cholic acid (<i>d</i>₄-cholic acid) in these rats, we determined its plasma concentrations and calculated the differential AUC values. Subsequently, we conducted a two-stage partial least-squares analysis in which 31 baseline metabolites were screened initially for predicting the individualized AUC values of <i>d</i>₄-cholic acid using the data of predose urine metabolites. Finally, network biology analysis was applied to give the biological interpretation of the individual variances in cholic acid metabolism and disposition, and the result further narrowed the selection of baseline metabolites from 31 to 2 (sarcosine and <i>S</i>-adenosyl-l-homocysteine) for such prediction. Collectively, this pharmacometabolomics research provided a new strategy for predicting individualized PK of endogenous drugs

One-Pot Synthesis of Ternary Pt–Ni–Cu Nanocrystals with High Catalytic Performance

Shape-controlled synthesis of multicomponent metal nanocrystals (NCs) bounded by high-index facets (HIFs) is of significant importance in the design and synthesis of highly active catalysts. It is a highly challenging task to design and synthesize ternary alloy NCs with HIFs due to the formidable difficulties in controlling the nucleation/growth kinetics of NCs in the presence of three metal precursors with different reduction potentials. We report herein, for the first time, the preparation of Pt–Ni–Cu alloy NCs by tuning their shape from crossed, dendritic, concave nanocubic (CNC) to rough octahedral (ROH) NCs through a facile one-pot solvothermal synthesis method. Specifically, the crossed and CNC Pt–Ni–Cu alloy NCs are bounded by high-index {<i>hk</i>0} facets and ROH with rich lattice defects. The electrocatalytic activities of these Pt–Ni–Cu alloy NCs toward methanol and formic acid oxidation were tested. It was shown that these Pt–Ni–Cu alloy NCs exhibited enhanced activity and stability compared to commercial Pt black and Pt/C catalysts as well as previous Pt–Ni and Pt CNCs under the same reaction conditions, demonstrating the superior electrocatalytic activity of Pt–Ni–Cu ternary alloys compared to monometal and binary Pt–Ni NCs. Surprisingly, we have found that the Pt–Ni–Cu ROH NCs have exhibited a higher specific catalytic activity than the crossed and CNC Pt–Ni–Cu alloy NCs with HIFs. The electronic and structure effects have been extensively discussed to shed light on the excellent electrocatalytic performance of Pt–Ni–Cu ROH NCs

Synthesis of 17, 21, 23, and 25.

<p>Reagents and conditions: a. TsOH, ethanol; 0°C, NaBH₄; b. K₂CO₃, ethanol; c. Pd/C, H₂, RT, 12 h; d. BBr₃, CH₂Cl₂, -20°C, 2 h; RT, 4 h. e. Et₃N, CH₂Cl₂; f. 180°C, neat, N₂.</p

Inhibitory effect of gigantol and its analogs on AR activity¹.

<p>¹The results are expressed as mean ± SD (n = 3).</p><p>Abbreviation: NA, no activity</p><p>*<i>P</i> < 0.01, vs. Extractive gigantol.</p><p>Inhibitory effect of gigantol and its analogs on AR activity<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141092#t001fn001" target="_blank">¹</a>.</p

Synthesis of 4, 5, 8, 10, 14, and gigantol.

<p>Reagents and conditions: a. NaBH₄, MeOH; b. PBr₃, pyridine, 0°C; c. P(OEt)₃, 120°C; d. different aldehydes, CH₃ONa, 0°C to room temperature (RT), 12 h; e. Pd/C, H₂, RT, 12 h; f. BBr₃, CH₂Cl₂, -20°C, 2 h; RT, 4 h; g. NaH, ethanethiol, DMF, N₂, reflux; h. MOMCl, <i>i</i>-Pr₂NEt, CH₂Cl₂, 0°C, 1 h; RT, 12 h; i. diethyl naphthalen-1-ylmethylphosphonate, CH₃ONa, 0°C, 1 h; rt, 12 h; j. 2 M HCl, methanol, 50°C, 1 h; k. BnBr, 18-crown-6, K₂CO₃, reflux, 9 h.</p

Inhibitory effect of gigantol and its analogs on iNOS activity¹.

<p>¹The results are expressed as mean ± SD (n = 3). Abbreviation: NA, no activity.</p><p>Inhibitory effect of gigantol and its analogs on iNOS activity<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141092#t002fn001" target="_blank">¹</a>.</p

Gigantol analogs at 0.1, 0.5, and 1.0 μg·mL^-1 on viability of HLECs treated with 250 mmol·L^-1 D-galactose for 72 h.

<p>Cell viability was determined by the MTT assay in the absence (Con) and presence (all other groups) of D-galactose. Ext-G refers to gigantol extracted from dendrobii. Viability (mean ± SD, n = 3) is expressed as the percentage of viable cells in the treatment to those of the Con. ^#<i>P</i> < 0.01 vs. Con, *<i>P</i> < 0.05 vs. D-galactose.</p