The fate of ingredients in and impact on cigarette smoke

Exploring Metabolic Characteristics in Different Geographical Locations and Yields of Nicotiana tabacum L. Using Gas Chromatography-Mass Spectrometry Pseudotargeted Metabolomics Combined with Chemometrics

The quality of crops is closely associated with their geographical location and yield, which is reflected in the composition of their metabolites. Hence, we employed GC-MS pseudotargeted metabolomics to investigate the metabolic characteristics of high-, medium-, and low-yield Nicotiana tabacum (tobacco) leaves from the Bozhou (sweet honey flavour) and Shuicheng (light flavour) regions of Guizhou Province. A total of 124 metabolites were identified and classified into 22 chemical categories. Principal component analysis revealed that the geographical location exerted a greater influence on the metabolic profiling than the yield. Light-flavoured tobacco exhibited increased levels of sugar metabolism- and glycolysis-related intermediate products (trehalose, glucose-6-phosphate, and fructose-6-phosphate) and a few amino acids (proline and leucine), while sweet honey-flavoured tobacco exhibited increases in the tricarboxylic acid cycle (TCA cycle) and the phenylpropane metabolic pathway (p-hydroxybenzoic acid, caffeic acid, and maleic acid). Additionally, metabolite pathway enrichment analysis conducted at different yields and showed that both Shuicheng and Bozhou exhibited changes in six pathways and four of them were the same, mainly C/N metabolism. Metabolic pathway analysis revealed higher levels of intermediates related to glycolysis and sugar, amino acid, and alkaloid metabolism in the high-yield samples, while higher levels of phenylpropane in the low-yield samples. This study demonstrated that GC-MS pseudotargeted metabolomics-based metabolic profiling can be used to effectively discriminate tobacco leaves from different geographical locations and yields, thus facilitating a better understanding of the relationship between metabolites, yield, and geographical location. Consequently, metabolic profiles can serve as valuable indicators for characterizing tobacco yield and geographical location.

An Approach to Flavor Chemical Thermal Degradation Analysis

Toxicological evaluations of flavor chemicals for use in inhalation products that utilize heat for aerosol generation are complicated because of the potential effect heat may have on the flavor chemical. The objective was to develop a thermal degradation technique to screen flavor chemicals as part of a toxicological testing program for their potential use in ENDS formulations. Based upon published data for acetaldehyde, acrolein, and glycidol from ENDS products (common thermal degradants of propylene glycol and glycerin), the pyrolizer temperature was adjusted until a similar ratio of acetaldehyde, acrolein, and glycidol was obtained from a 60/40 ratio (v/v) of glycerin/propylene glycol via GC/MS analysis. For each of 90 flavor chemicals, quantitative measurements of acetaldehyde, acrolein, and glycidol, in addition to semiquantitative non-targeted analysis tentatively identifying chemicals from thermal degradation, were obtained. Twenty flavor chemicals transferred at greater than 99% intact, another 26 transferred at greater than 95% intact, and another 15 flavor chemicals transferred at greater than 90% intact. Most flavor chemicals resulted in fewer than 10-12 tentatively identified thermal degradants. The practical approach to the thermal degradation of flavor chemicals provided useful information as part of the toxicological evaluation of flavor chemicals for potential use in ENDS formulations.

Aldehyde and Volatile Organic Compound Yields in Commercial Cigarette Mainstream Smoke Are Mutually Related and Depend on the Sugar and Humectant Content in Tobacco

Introduction

The World Health Organization (WHO) Framework Convention on Tobacco control recognizes the need for tobacco product regulation. In line with that, the WHO Study Group on Tobacco Product Regulation (TobReg) proposed to regulate nine toxicants in mainstream cigarette smoke, including aldehydes, volatile organic compounds (VOCs), and carbon monoxide (CO). We analyzed their relations in 50 commercially available cigarette brands, using two different smoking regimes, and their dependence on sugar and humectant concentrations in tobacco filler.

Methods

We measured sugar and humectant in tobacco filler and aldehydes, VOCs, and tar, nicotine, and CO (TNCO) in mainstream smoke. The general statistics, correlations between emission yields, and correlations between contents and emissions yields were determined for these data.

Results

For aldehydes, several significant correlations were found with precursor ingredients in unburnt tobacco when smoked with the Intense regime, most prominently for formaldehyde with sucrose, glucose, total sugars, and glycerol. For VOCs, 2,5-dimethylfuran significantly correlates with several sugars under both International Standards Organization (ISO) and Intense smoking conditions. A correlation network visualization shows connectivity between a sugar cluster, an ISO cluster, and an Intense cluster, with Intense formaldehyde as a central highest connected hub.

Conclusions

Our multivariate analysis showed several strong connections between the compounds determined. The toxicants proposed by WHO, in particular, formaldehyde, can be used to monitor yields of other toxicants under Intense conditions. Emissions of formaldehyde, acetaldehyde, acrolein, and 2,5-dimethylfuran may decrease when sugar and humectants contents are lowered in tobacco filler.

Implications

Our findings suggest that the aldehydes and VOCs proposed by TobReg are a representative selection for smoke component market monitoring purposes. In particular, formaldehyde yields may be useful to monitor emissions of other toxicants under Intense conditions. Since the most and strongest correlations were observed with the Intense regime, policymakers are advised to prescribe this regime for regulatory purposes. Policymakers should also consider sugars and humectants contents as targets for future tobacco product regulations, with the additional advantage that consumer acceptance of cigarette smoke is proportional to their concentrations in the tobacco blend.

Assessment of priority tobacco additives per the requirements of the EU Tobacco Products Directive (2014/40/EU): Part 1: Background, approach, and summary of findings

This paper is part of a series of 3 publications and describes the non-clinical and clinical assessment performed to fulfill the regulatory requirement per Art. 6 (2) of the EU Tobacco Products Directive 2014/40/EU; under which Member States shall require manufacturers and importers of cigarettes and roll-your-own tobacco containing an additive that is included in the priority list established by Commission Implementing Decision (EU) 2016/787 to carry out comprehensive studies. The Directive requires manufacturers and importers of cigarettes and Roll Your Own tobacco to examine for each additive whether it; contributes to and increases the toxicity or addictiveness of tobacco products to a significant or measurable degree; if it leads to a characterizing flavor of the product; if it facilitates inhalation or nicotine uptake, and if it results in the formation of CMR (carcinogenic, mutagenic and reprotoxic) constituents and if these substances increase the CMR properties of the respective tobacco product to a significant or measurable degree. This publication gives an overview on comprehensive smoke chemistry, in vitro toxicity, and human clinical studies commissioned by the members of the Priority Additives Tobacco Consortium to independent Contract Research Organizations (CROs) where the emissions of test cigarettes containing priority additives were compared to emissions emerging from an additive-free reference cigarette. Whilst minor changes in smoke chemistry parameters were observed when comparing emissions from test cigarettes with emissions from additive-free reference cigarettes, only two of the additives (sorbitol and guar gum) tested led to significant increases in a limited number of smoke constituents. These changes were not observed when sorbitol or guar gum were tested in a mixture with other priority additives. None of the priority additives resulted in increases in in vitro toxicity (Ames, Micronucleus, Neutral Red Uptake) or led to changes in smoking behavior or absorption (rate or amount) of nicotine measured during the human clinical study as compared to the additive-free reference cigarette.

Investigation of menthol content and transfer rates in cigarettes and Tobacco Heating System 2.2

Menthol cigarettes account for a significant market share in many countries. However, little recent data exists on menthol levels in cigarettes and in mainstream smoke, limited to some markets or specific cigarette designs, such as cigarettes containing capsules filled with flavoring liquids. Samples of mentholated cigarettes bought worldwide with a variety of cigarette designs were analyzed for menthol content in cigarettes and in cigarette mainstream smoke with two analytical machine smoking regimes. A wide range of menthol content in cigarettes, from 1 to 22 mg/cigarette, was observed. The transfer of menthol to the cigarette mainstream smoke was generally slightly higher than the transfer of nicotine, with a range of 17%-40% using an intense smoking regime and 1%-17% using the ISO smoking regime. For the Tobacco Heating System (THS) 2.2, the menthol content was 12.8 mg/stick, and the transfer of menthol into the aerosol was about 17% with the ISO intense smoking regime, similar to the transfer of nicotine. The menthol content of the novel product THS 2.2 corresponds to the midpoint of the menthol content range of cigarettes, and the transfer of menthol to its aerosol is in the low range of cigarette menthol transfer.

Contribution of tobacco composition compounds to characteristic aroma of Chinese faint-scent cigarettes through chromatography analysis and partial least squares regression

To further explore the aroma mechanism of Chinese faint-scent cigarettes, the contribution of tobacco leaf composition, including six kinds of saccharides, eight tobacco alkaloids, seventeen kinds of organic acids, eighteen kinds of amino acids and four ions (Na+, K+, Mg2+ and Ca2+), on aroma quality characteristic (freshness, flowery and acidic notes) of faint-scent cigarettes was analyzed by chromatography and PLSR. The results showed that (i) xylose, fructose, glucose, maltose and sucrose were negatively correlated to acidic note, while galactose showed significantly positive correlation to acidic note. (ii) Phenylalanine and proline showed significant and positive correlation with characteristic aromas. Proline contributed to freshness and flowery, while leucine significantly contributed to acidic note. (iii) Most organic acids were significantly correlated to characteristic aromas. Palmitic acid and stearic acid contributed to the freshness, while dodecanoic acid and palmitic acid significantly contributed to flowery. (iv) Tobacco Na ion plays negative and significant correlation to acidic note.

Fate of pyrazines in the flavored liquids of e-cigarettes

Popularity of electronic cigarettes (ECIGs) has increased tremendously among young people, in part due to flavoring additives in ECIG liquids. Pyrazines are an important class of these additives, and their presence in tobacco cigarettes has been correlated with increased acceptability of smoking among smokers and bystanders. Pyrazine use by the tobacco industry is therefore thought to encourage smoking. However, the extent of transfer of pyrazines present in the liquid to aerosols upon vaping remains unclear. We present a simple analytical method to quantify six pyrazine derivatives in liquids and aerosols of ECIGs that allows the isolation of pyrazines from interfering compounds, like nicotine. Standard pyrazine solutions and commercial ECIG samples of different brands and flavors were tested for their pyrazine content in the liquids and in the generated aerosols from these solutions. Testing on ECIG commercial liquids revealed a heterogeneous distribution in the levels and types of pyrazines, with acetyl and alkyl pyrazines present in more than 70% of the samples. This method confirmed that pyrazine additives are common in ECIG and that labels do not usually reflect the type and quantity of pyrazines in the liquid. Pyrazines were not correlated with the nicotine content or the brand of the liquid. The aerosols showed similar pyrazine profiles to their corresponding liquids. The efficiency of transfer of pyrazines into the particle phase was approximately 46%. Therefore, addition of pyrazines to ECIGs should be regulated, because they act synergistically with nicotine to increase product appeal, ease smoking initiation, and discourage cessation.

Oxidative and inert pyrolysis on-line coupled to gas chromatography with mass spectrometric detection: On the pyrolysis products of tobacco additives

According to European legislation, tobacco additives may not increase the toxicity or the addictive potency of the product, but there is an ongoing debate on how to reliably characterize and measure such properties. Further, too little is known on pyrolysis patterns of tobacco additives to assume that no additional toxicological risks need to be suspected. An on-line pyrolysis technique was used and coupled to gas chromatography-mass spectrometry (GC/MS) to identify the pattern of chemical species formed upon thermal decomposition of 19 different tobacco additives like raw cane sugar, licorice or cocoa. To simulate the combustion of a cigarette it was necessary to perform pyrolysis at inert conditions as well as under oxygen supply. All individual additives were pyrolyzed under inert or oxidative conditions at 350, 700 and 1000°C, respectively, and the formation of different toxicants was monitored. We observed the generation of vinyl acrylate, fumaronitrile, methacrylic anhydride, isobutyric anhydride and 3-buten-2-ol exclusively during pyrolysis of tobacco additives. According to the literature, these toxicants so far remained undetectable in tobacco or tobacco smoke. Further, the formation of 20 selected polycyclic aromatic hydrocarbons (PAHs) with molecular weights of up to 278Da was monitored during pyrolysis of cocoa in a semi-quantitative approach. It was shown that the adding of cocoa to tobacco had no influence on the relative amounts of the PAHs formed.

Tobacco alkaloids reduction by casings added/enzymatic hydrolysis treatments assessed through PLSR analysis

Based on encouraged development of potential reduced-exposure products (PREPs) by the US Institute of Medicine, casings (glucose and peptides) added treatments (CAT) and enzymatic (protease and xylanase) hydrolysis treatments (EHT) were developed to study their effect on alkaloids reduction in tobacco and cigarette mainstream smoke (MS) and further investigate the correlation between sensory attributes and alkaloids. Results showed that the developed treatments reduced nicotine by 14.5% and 24.4% in tobacco and cigarette MS, respectively, indicating that both CAT and EHT are potentially effective for developing lower-risk cigarettes. Sensory and electronic nose analysis confirmed the significant influence of treatments on sensory and cigarette MS components. PLSR analysis demonstrated that tobacco alkaloids were positively correlated to the off-taste, irritation and impact attributes, and negatively correlated to the aroma and softness attributes. Additionally, nicotine and anabasine from tobacco leaves positively contributed to the impact attribute, while they negatively contributed to the aroma attribute (P<0.05). Meanwhile, most alkaloids in cigarette MS positively contributed to the impact and irritation attributes (P<0.05). Hence, this study paved a way to better understand the correlation between tobacco alkaloids and sensory attributes.

An ethyl acetate fraction of Moringa oleifera Lam. Inhibits human macrophage cytokine production induced by cigarette smoke

Moringa oleifera Lam. (MO) has been reported to harbor anti-oxidation and anti-inflammatory activity and useful in the treatment of inflammatory diseases. However, despite these findings there has been little work done on the effects of MO on immune cellular function. Since macrophages, TNF and related cytokines play an important pathophysiologic role in lung damage induced by cigarette smoke, we examined the effects of MO on cigarette smoke extract (CSE)-induced cytokine production by human macrophages. An ethyl acetate fraction of MO (MOEF) was prepared from fresh leaves extract of Moringa and shown to consist of high levels of phenolic and antioxidant activities. Human monocyte derived macrophages (MDM) pre-treated with varying concentrations of MOEF showed decreased production of TNF, IL-6 and IL-8 in response to both LPS and CSE. The decrease was evident at both cytokine protein and mRNA levels. Furthermore, the extract inhibited the expression of RelA, a gene implicated in the NF-κB p65 signaling in inflammation. The findings highlight the ability of MOEF to inhibit cytokines (IL-8) which promote the infiltration of neutrophils into the lungs and others (TNF, IL-6) which mediate tissue disease and damage.

Metabolic profile and genotoxicity in obese rats exposed to cigarette smoke

OBJECTIVE

Experimental studies have shown that exposure to cigarette smoke has negative effects on lipid metabolism and oxidative stress status. Cigarette smoke exposure in nonpregnant and pregnant rats causes significant genotoxicity (DNA damage). However, no previous studies have directly evaluated the effects of obesity or the association between obesity and cigarette smoke exposure on genotoxicity. Therefore, the aim of the present investigation was to evaluate DNA damage levels, oxidative stress status and lipid profiles in obese Wistar rats exposed to cigarette smoke.

DESIGN AND METHODS

Female rats subcutaneously (s.c.) received a monosodium glutamate solution or vehicle (control) during the neonatal period to induce obesity. The rats were randomly distributed into three experimental groups: control, obese exposed to filtered air, and obese exposed to tobacco cigarette smoke. After a 2-month exposure period, the rats were anesthetized and killed to obtain blood samples for genotoxicity, lipid profile, and oxidative stress status analyses.

RESULTS

The obese rats exposed to tobacco cigarette smoke presented higher DNA damage, triglycerides, total cholesterol, free fatty acids, VLDL-c, HDL-c, and LDL-c levels compared to control and obese rats exposed to filtered air. Both obese groups showed reduced SOD activity. These results showed that cigarette smoke enhanced the effects of obesity.

CONCLUSION

In conclusion, the association between obesity and cigarette smoke exposure exacerbated the genotoxicity, negatively impacted the biochemical profile and antioxidant defenses and caused early glucose intolerance. Thus, the changes caused by cigarette smoke exposure can trigger the earlier onset of metabolic disorders associated with obesity, such as diabetes and metabolic syndrome.

Determination of pesticide residues in cannabis smoke

The present study was conducted in order to quantify to what extent cannabis consumers may be exposed to pesticide and other chemical residues through inhaled mainstream cannabis smoke. Three different smoking devices were evaluated in order to provide a generalized data set representative of pesticide exposures possible for medical cannabis users. Three different pesticides, bifenthrin, diazinon, and permethrin, along with the plant growth regulator paclobutrazol, which are readily available to cultivators in commercial products, were investigated in the experiment. Smoke generated from the smoking devices was condensed in tandem chilled gas traps and analyzed with gas chromatography-mass spectrometry (GC-MS). Recoveries of residues were as high as 69.5% depending on the device used and the component investigated, suggesting that the potential of pesticide and chemical residue exposures to cannabis users is substantial and may pose a significant toxicological threat in the absence of adequate regulatory frameworks.