In vitro toxicity and chemical analysis of e-cigarette aerosol produced amid dry hitting.

Dry hitting, a phenomenon produced by e-cigarettes with refillable cartridges when the liquid in the coil is low, is a common occurrence among regular vapers despite being an unintended consequence of the device. This phenomenon's hazard to public health is still unknown and needs further investigation. Lung cells cultured at the air-liquid interface were exposed to vaped aerosol consisting of 3 % w/v ethyl maltol in propylene glycol for three-second puffs every 30 seconds for 80 total puffs with either dry hit or saturated conditions. Cytotoxicity was measured colorimetrically. The thermal degradation of the heating coils and wicks was visualized using scanning electron microscopy. The chemical byproducts in the aerosol were analyzed using proton nuclear magnetic resonance and inductively coupled plasma mass spectrometry. The results revealed a highly significant increase in cytotoxicity from dry hit treatments. Imaging showed thermal decomposition of the cotton wick after dry hitting, which was confirmed by energy dispersive x-ray spectroscopy with less oxygen in the dry hit cotton. Chemical byproducts were found via unique peaks in the dry hit condensate in the aromatic and alkene regions. Saturated condensate showed higher concentrations of detected metal species than dry-hit condensate. E-cigarette users should avoid dry hitting by refilling tanks or cartridges preemptively or by using disposable coils to avoid increased toxicity during vaping.

Effects of steam explosion-modified rice bran dietary fiber on volatile flavor compounds retention and release of red date-flavored naan (ethnic specialty food of Xinjiang) during storage.

This study explored the effects of steam explosion-modified rice bran dietary fiber (S-RBDF) on red date-flavored naan quality and flavor characteristics. The results revealed that the rheological properties of the dough were improved with the incremental addition of S-RBDF (0-5%). The microstructure revealed that adding an appropriate amount of S-RBDF (1-5%) enabled more starch granules to be embedded in the dough network. Notably, the addition of 5% S-RBDF resulted in naan with an optimum specific volume and texture, which consumers preferred. Additionally, gas chromatography-mass spectrometry analysis showed that adding S-RBDF to naan contributed to the retention and sustained release of pleasant volatile compounds (e.g. red date flavor, etc.), while inhibiting the development of unpleasant volatile compounds by delaying the oxidation and decomposition of lipids and preserving the antioxidant phenolic compounds, thus contributing to flavor maintenance of naan during storage. Overall, these results provided a foundation for developing high-quality flavored naan.

Design, synthesis, and anti-oomycete activity of 3-acyloxymaltol/ethyl maltol derivatives.

Twenty 3-acyloxymaltol/ethyl maltol derivatives (7a-j and 8a-j) were synthesized and evaluated in vitro for their anti-oomycete activity against Phytophthora capsici, respectively. Among all of twenty derivatives, more than half of the compounds 7f, 7h, 8a-h and 8j had anti-oomycete activity higher than the positive control zoxamide (EC50 = 22.23 mg/L), and the EC50 values of 18.66, 20.32, 12.80, 16.18, 10.59, 14.98, 16.80, 10.36, 15.32, 12.64, and 13.59 mg/L, respectively. Especially, compounds 8c and 8f exhibited the best anti-oomycete activity against P. capsici with EC50 values of 10.59 and 10.36 mg/L, respectively. Overall, hydroxyl group of maltol/ethyl maltol is important active modification site.

Ethyl maltol disrupt iron homeostasis in SH-SY5Y neuroblastoma cell line.

Ethyl Maltol (EM) is a commonly used flavoring compound and has been reported to bind iron and facilitate iron transport. Since EM is membrane permeable, the potential that it disrupts intracellular iron homeostasis was investigated. EM increased the labile iron pool in SH-SY5Y cells and increased iron-responsive protein activity using a reporter assay in the HEK293 cells. EM induced the expression of transferrin receptor 1 messenger RNA (mRNA) and decreased the expression of ferritin light chain protein in SH-SY5Y cells. Expression of the iron-responsive amyloid precursor protein attenuated the effects of EM on these iron-responsive genes. EM treatment decreased cell viability and increased DNA damage. EM also increased the level of phosphorylated p53 and the expression of the p53-regulated genes, p21, and 14-3-3σ. The expression of amyloid precursor protein (APP) attenuated the effects of EM on viability, DNA damage, and the p53 response. Overall, we suggest that EM decreases cell viability through a mechanism involving the p53 pathway. The attenuated responses observed in cells expressing APP suggest that the effects of EM are due to disrupting iron homeostasis.

Synthesis and Anti-Oomycete Preliminary Mechanism of Sulfonate Derivatives of Ethyl Maltol.

To discover novel molecules with unique mechanism against plant pathogenic oomycetes, sixteen new sulfonate derivatives of ethyl maltol (3a-p) were synthesized by structural modification of 2-ethyl-3-hydroxy-4H-pyran-4-one, and their anti-oomycete activity against a serious agricultural disease, Phytophthora capsici Leonian was determined in this study. Among all tested compounds, derivatives 3e, 3m and 3p exhibited the most potent anti-oomycete activity against P. capsici with EC50 values of 19.40, 21.04 and 31.10 mg/L, respectively; especially 3e and 3m showed the best promising and pronounced anti-oomycete activity than zoxamide (EC50 =26.87 mg/L). The results further proved that 4-tert-butylphenylsulfonyl group, 3-nitro-4-chlorophenylsulfonyl group and 8-quinolinesulfonyl group introduced at the hydroxy position of ethyl maltol or maltol were necessary for obtaining the most potent compounds. Further mechanism studies of P. capsici treated with 3e demonstrated that this compound can affect the growth of mycelia by disrupting the integrity of the membrane, and the higher the concentration of the compound is, the greater the degree of membrane integrity damage. These important results will pave the way for further modification of ethyl maltol to develop potential new fungicides.

Dispersive solid-phase extraction and dispersive liquid-liquid microextraction for the determination of flavor enhancers in ready-to-eat seafood by HPLC-PDA.

The dispersion solid-phase microextraction (DSPE) combined with dispersion liquid-liquid microextraction (DLLME) was developed as a rapid, simple and effective pretreatment method for the determination of flavor enhancers (maltol, ethyl maltol, vanillin, methyl vanillin, ethyl vanillin) of ready-to-eat seafood products (dried squid, baked squid, fried fish, steamed abalone). Under the optimized DSPE-DLLME method, the developed method exhibited low limits of quantitation (0.20-0.50 µg g-1) and excellent linearity (R2 ≥ 0.995). The recoveries of flavor enhancers in the actual samples were 83.7%-114.9%. Compared with traditional pretreatment methods, the developed DSPE-DLLME method was rapid (17 min) and easy to determine the flavor enhancers by high performance liquid chromatography with photodiode array detector (HPLC-PDA). In the actual samples, creamy compounds such as vanillin, methyl vanillin and ethyl vanillin were hardly found. However, the flavor compounds produced by thermal reactions such as maltol (except for dried squid 3) and ethyl maltol were present in all samples.

Flavored e-liquids increase cytoplasmic Ca2+ levels in airway epithelia.

E-cigarettes are noncombustible, electronic nicotine-delivery devices that aerosolize an e-liquid, i.e., nicotine, in a propylene glycol-vegetable glycerin vehicle that also contains flavors. While the effects of nicotine are relatively well understood, more information regarding the potential biological effects of the other e-liquid constituents is needed. This is a serious concern, because e-liquids are available in >7,000 distinct flavors. We previously demonstrated that many e-liquids affect cell growth/viability through an unknown mechanism. Since Ca2+ is a ubiquitous second messenger that regulates cell growth, we characterized the effects of e-liquids on cellular Ca2+ homeostasis. To better understand the extent of this effect, we screened e-liquids for their ability to alter cytosolic Ca2+ levels and found that 42 of 100 flavored e-liquids elicited a cellular Ca2+ response. Banana Pudding (BP) e-liquid, a representative e-liquid from this group, caused phospholipase C activation, endoplasmic reticulum (ER) Ca2+ release, store-operated Ca2+ entry (SOCE), and protein kinase C (PKCα) phosphorylation. However, longer exposures to BP e-liquid depleted ER Ca2+ stores and inhibited SOCE, suggesting that this e-liquid may alter Ca2+ homeostasis by short- and long-term mechanisms. Since dysregulation of Ca2+ signaling can cause chronic inflammation, ER stress, and abnormal cell growth, flavored e-cigarette products that can elicit cell Ca2+ responses should be further screened for potential toxicity.

Evaluation and comparison of zinc absorption level from 2-Alkyle 3-Hydroxy pyranon-zinc complexes and zinc sulfate in rat in vivo.

BACKGROUND: Although zinc sulfate has been used to improve disorders originated from zinc deficiency, its low compliance is due to gastrointestinal complications; therefore, other zinc compounds have been suggested as replacers for zinc deficient people. The objective of this study was to evaluate and compare the absorption of ethyl and methyl zinc-maltol with that of zinc sulfate to substitute zinc sulfate with those complexes. MATERIALS AND METHODS: After five weeks of being fed by zinc deficient food, zinc deficient rats were divided into four groups randomly receiving medicinal solutions of zinc sulfate, zinc ethyl maltol and zinc methyl maltol using feeding tube method for two weeks while the control was received distilled water. Serum zinc concentration and ALP (Alkaline Phosphatase) and LDH (Lactate Dehydrogenase) activity of rats were determined before and after the study. Statistical analyses were performed using SPSS 11.5. The study was conducted from 2008 to 2010. RESULTS: Serum zinc concentration and enzyme activity in all groups receiving drug solution increased. The most and least increase were in zinc sulfate and zinc methyl maltol groups, respectively. The difference between zinc methyl maltol and zinc sulfate group was significant (P < 0.05); however, this difference was not significant in the case of zinc ethyl maltol. CONCLUSION: Zinc ethyl maltol can be a suitable and preferable substitute for zinc sulfate.

Taste-modifying technology of Jinzhen Oral Liquid / 中草药

Objective: To study the optimal method for taste-modifying of Jinzhen Oral Liquid (JOL). Methods: Active carbon adsorption method was optimized through L9(34) orthogonal test and with the change rate of concentration of bilirubin as index, and the different taste-modifying prescriptions were evaluated by the fuzzy mathematics synthetic evaluation system. Results: The optimal adsorption conditions were as follows: The pH value of the mixture of Cornu Bubali and artificial Calculus ovis was adjusted to 7.0 at 50 °C with 0.25% activated carbon, and stirring for 10 min. The optimal formula ingredient was as follows: 15.0 mg ethyl maltol, 5.0 g CMC-Na, 1.0 g steviosin, and 0.5 g orange flavor in 1 000 mL JOL. Conclusion: The taste-modifying prescriptions provide great value for further scale production.

Simultaneous kinetic-spectrophotometric determination of maltol and ethyl maltol in food samples by using chemometrics.

A fast and accurate procedure has been researched and developed for the simultaneous determination of maltol and ethyl maltol, based on their reaction with iron(III) in the presence of o-phenanthroline in sulfuric acid medium. This reaction was the basis for an indirect kinetic spectrophotometric method, which followed the development of the pink ferroin product (λmax=524nm). The kinetic data were collected in the 370-900nm range over 0-30s. The optimized method indicates that individual analytes followed Beer's law in the concentration range of 4.0-76.0mgL(-1) for both maltol and ethyl maltol. The LOD values of 1.6mgL(-1) for maltol and 1.4mgL(-1) for ethyl maltol agree well with those obtained by the alternative high performance liquid chromatography with ultraviolet detection (HPLC-UV). Three chemometrics methods, principal component regression (PCR), partial least squares (PLS) and principal component analysis-radial basis function-artificial neural networks (PC-RBF-ANN), were used to resolve the measured data with small kinetic differences between the two analytes as reflected by the development of the pink ferroin product. All three performed satisfactorily in the case of the synthetic verification samples, and in their application for the prediction of the analytes in several food products. The figures of merit for the analytes based on the multivariate models agreed well with those from the alternative HPLC-UV method involving the same samples.