Analysis of Scopoletin and Caffeic Acid in Tobacco by GC–MS After a Rapid Derivatization Procedure

Harmful and Potentially Harmful Constituents in E-Liquids and Aerosols from Electronic Nicotine Delivery Systems (ENDS)

In 2012, the U.S. Food & Drug Administration (FDA) published an established list of 93 harmful and potentially harmful constituents (HPHCs) targeting four tobacco product types (cigarettes, cigarette tobacco, roll-your-own tobacco, smokeless tobacco). In 2016, the FDA finalized the deeming rule to regulate electronic nicotine delivery systems (ENDS). However, knowledge gaps exist regarding whether certain HPHCs are present in ENDS e-liquids and aerosols. We identified and addressed these gaps by conducting literature searches and then experimentally quantifying HPHCs in the e-liquid and aerosol of 37 ENDS brands based on gaps in the literature. The literature searches identified 66 e-liquid HPHCs and 68 aerosol HPHCs that have limited to no information regarding the quantifiability of these constituents. A contracted ISO 17025 accredited laboratory performed the HPHC quantifications. The availability of validated analytical methods in the contracted laboratory determined the HPHCs included in the study scope (63/66 for e-liquids, 64/68 for aerosols). Combining the results from the quantifications and literature searches, 36 (39%) and 34 (37%) HPHCs were found quantifiable (≥limit of quantification [LOQ]) in ENDS e-liquids and aerosols, respectively, with 25 HPHCs being quantifiable in both matrices. Quantifiability results imply potential HPHC transfers between matrices, leaching from components, or formations from aerosol generation. The study results can inform the scientific basis for manufacturers and regulators regarding regulatory requirements for HPHC reporting. The HPHC quantities can also inform evaluations of the public health impact of ENDS and public communications regarding ENDS health risks.

Metabolomics Provides Novel Insights into the Potential Toxicity Associated with Heated Tobacco Products, Electronic Cigarettes, and Tobacco Cigarettes on Human Bronchial Epithelial BEAS-2B Cells

Smoking is an established risk factor for various pathologies including lung cancer. Electronic cigarettes (e-cigs) and heated tobacco products (HTPs) have appeared on the market in recent years, but their safety or, conversely, their toxicity has not yet been demonstrated. This study aimed to compare the metabolome of human lung epithelial cells exposed to emissions of e-cigs, HTPs, or 3R4F cigarettes in order to highlight potential early markers of toxicity. BEAS-2B cells were cultured at the air-liquid interface and exposed to short-term emissions from e-cigs set up at low or medium power, HTPs, or 3R4F cigarettes. Untargeted metabolomic analyses were performed using liquid chromatography coupled with mass spectrometry. Compared to unexposed cells, both 3R4F cigarette and HTP emissions affected the profiles of exogenous compounds, one of which is carcinogenic, as well as those of endogenous metabolites from various pathways including oxidative stress, energy metabolism, and lipid metabolism. However, these effects were observed at lower doses for cigarettes (2 and 4 puffs) than for HTPs (60 and 120 puffs). No difference was observed after e-cig exposure, regardless of the power conditions. These results suggest a lower acute toxicity of e-cig emissions compared to cigarettes and HTPs in BEAS-2B cells. The pathways deregulated by HTP emissions are also described to be altered in respiratory diseases, emphasizing that the toxicity of HTPs should not be underestimated.

Harmful and Potentially Harmful Constituents in the Filler and Smoke of Tobacco-Containing Tobacco Products

The U.S. Food and Drug Administration established a list of 93 harmful and potentially harmful constituents (HPHCs) in tobacco products. While HPHCs are required to be submitted for tobacco products, knowledge gaps exist regarding which tobacco-containing tobacco product (TCTP, i.e., tobacco products that contain tobacco(s) as a component) types (cigarettes, cigars, roll-your-own tobaccos [RYOs], pipe tobaccos [pipes], smokeless tobacco products [STPs], waterpipe tobaccos [waterpipes]) and matrices (filler, smoke) contain which HPHCs. This study identified and addressed such gaps by conducting literature searches and measuring the amount of HPHCs in TCTP types and matrices. First, literature searches, performed for cigarettes, RYOs, and STPs for publications up to 2014 and for cigars, pipes, and waterpipes for publications up to 2016, identified knowledge gaps for the 93 HPHCs (or 119 HPHCs if cresols [o-, m-, p-cresol] are counted as 3 and chlorinated dioxins/furans as 25) across TCTP types and matrices. Then, three ISO 17025 accredited laboratories including two subcontracted laboratories performed the HPHC quantifications. Inclusion of the HPHCs, TCTP types, and matrices in the study scope was also determined by the availability of validated analytical methods in each laboratory. Eleven (9%) HPHCs are quantifiable in all brands for all TCTP types and matrices, 33 (28%) HPHCs are not quantifiable in any brands of any TCTP type and matrix, and 74 (63%) HPHCs are quantifiable only in some brands across TCTP types and matrices examined. Understanding the quantifiability of HPHCs in each TCTP type and matrix can inform the scientific basis for manufacturers regarding the regulatory requirements for reporting HPHCs. The quantity of HPHCs observed can also inform the evaluation of the public health impact of HPHCs and public communications regarding the health risks of tobacco products.

Changes in key constituents of clonally propagated Artemisia annua L. during preparation of compressed leaf tablets for possible therapeutic use

Artemisia annua L., long used as a tea infusion in traditional Chinese medicine, produces artemisinin. Although artemisinin is currently used as artemisinin-based combination therapy (ACT) against malaria, oral consumption of dried leaves from the plant showed efficacy and will be less costly than ACT. Many compounds in the plant have some antimalarial activity. Unknown, however, is how these plant components change as leaves are processed into tablets for oral consumption. Here we compared extracts from fresh and dried leaf biomass with compressed leaf tablets of A. annua. Using GC-MS, nineteen endogenous compounds, including artemisinin and several of its pathway metabolites, nine flavonoids, three monoterpenes, a coumarin, and two phenolic acids, were identified and quantified from solvent extracts to determine how levels of these compounds changed during processing. Results showed that compared to dried leaves, artemisinin, arteannuin B, artemisinic acid, chlorogenic acid, scopoletin, chrysoplenetin, and quercetin increased or remained stable with powdering and compression into tablets. Dihydroartemisinic acid, monoterpenes, and chrysoplenol-D decreased with tablet formation. Five target compounds were not detectable in any of the extracts of this cultivar. In contrast to the individually measured aglycone flavonoids, using the AlCl₃ method, total flavonoids increased nearly fivefold during the tablet formation. To our knowledge this is the first study documenting changes that occurred in processing dried leaves of A. annua into tablets. These results will improve our understanding of the potential use of not only this medicinal herb, but also others to afford better quality control of intact plant material for therapeutic use.

Optimizing the models for rapid determination of chlorogenic acid, scopoletin and rutin in plant samples by near-infrared diffuse reflectance spectroscopy

Polyphenols in plant samples have been extensively studied because phenolic compounds are ubiquitous in plants and can be used as antioxidants in promoting human health. A method for rapid determination of three phenolic compounds (chlorogenic acid, scopoletin and rutin) in plant samples using near-infrared diffuse reflectance spectroscopy (NIRDRS) is studied in this work. Partial least squares (PLS) regression was used for building the calibration models, and the effects of spectral preprocessing and variable selection on the models are investigated for optimization of the models. The results show that individual spectral preprocessing and variable selection has no or slight influence on the models, but the combination of the techniques can significantly improve the models. The combination of continuous wavelet transform (CWT) for removing the variant background, multiplicative scatter correction (MSC) for correcting the scattering effect and randomization test (RT) for selecting the informative variables was found to be the best way for building the optimal models. For validation of the models, the polyphenol contents in an independent sample set were predicted. The correlation coefficients between the predicted values and the contents determined by high performance liquid chromatography (HPLC) analysis are as high as 0.964, 0.948 and 0.934 for chlorogenic acid, scopoletin and rutin, respectively.

Rapid and sensitive analysis of three polyphenols in tobacco by CE using homemade C(4)D with a mini detection cell

A rapid, sensitive, and practical CE with C(4) D detection was developed for the analysis of three polyphenols (rutin, scopoletin, and chlorogenic acid) in tobacco samples. The constructed mini detection cell (12 mm × 10 mm × 10 mm) of C(4) D featured with small inner cell volume (∼2 nL), smaller noise (<0.9 mV), repeatability, high strength and durableness. Three polyphenols were ultrasonically extracted with methanol-water (70:30, v/v) solution following SPE cleanup. The CE method was optimized with the running buffer of 150 mmol L(-1) 2-amino-2-methyl-1-propanol (pH 11.2), and the applied separation voltage of +20 kV over a capillary of 50 μm id × 375 μm od × 50 cm (38 cm to the C(4) D window, 41.5 cm to the UV detector window), which gave a baseline separation of three polyphenols within ca. 6 min. The method provided the limits of quantification (S/N = 10) at about 0.08-0.15 μg g(-1) for three polyphenols, whereas the overall recoveries ranged from 82% to 88%. The proposed method has been successfully applied to measure three polyphenols in the actual tobacco samples, and their contents were calculated and evaluated.

Analysis of phenolic compounds by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry in senescent and water-stressed tobacco

Evaluation of a significant part of the phenylpropanoid pathway metabolites is facilitated by the fast high-performance liquid chromatography with electrospray ionization tandem mass spectrometry (LC-MS/MS) analytical method. The technology described was applied in tobacco plants (Nicotiana tabacum L. cv. Wisconsin) to identify 20 phenolic compounds and to detect differences in phenylpropanoid profiles in two types of experiments. In the first one, senescent and non-senescent parts of flowering plants were compared, while in the second, watered plants were compared with water-stressed young plants. The 20 identified phenolic compounds were: seven hydroxycinnamoylquinic acids, seven hydroxycinnamic acid glucosides, one salicylic acid glucoside, two conjugated flavonols with disaccharides, and three hydroxycinnamic acid amides (HCAA) of putrescine. In general, the levels of phenylpropanoid compounds increased under water stress or senescent conditions, with the exception of HCAA, which decreased in senescent samples, and 4-O-p-coumaroylquinic acid and trihydroxycinamic acid-O-glucoside, which did not change in both experiments. The main product in all the samples was 5-O-caffeoylquinic acid (neochlorogenic acid). Another compound, kaempferol-7-O-neohesperidoside, was tentatively identified for the first time in tobacco plants. This method, which can be applied in other plant species, allows a simple and efficient comparative study of metabolite profile variations (qualitative and quantitative) in response to different physiological and/or environmental plant situations.