Comprehensive Chemical Characterization of Natural American Spirit Cigarettes

Reactions of [13C]-labelled tobacco smoke with DNA to generate selected adducts formed without metabolic activation

DNA adducts are central in the carcinogenic process because they can cause miscoding leading to permanent mutations in important genes involved in carcinogenesis. While it is known that tobacco smoking leads to increased levels of multiple DNA adducts, most DNA adducts detected to date in humans cannot be explicitly attributed to smoking but instead have various possible exogenous and endogenous sources. We plan to probe the tobacco source of DNA adducts by providing carbon-13 labelled ([13C]-labelled) cigarettes to smokers and analyzing [13C]-labelled DNA adducts in their oral cells to determine which adducts arise from smoking. Prior to conducting studies in humans, we first report here proof-of-principle machine smoking experiments to evaluate carbon isotopologues of (a) selected carbonyls and (b) DNA adducts resulting from direct exposure of cigarette smoke vapour-phase to calf-thymus DNA. The smoke of the study cigarettes, made from a 50:50 mixture of [13C]-labelled tobacco and a popular commercial tobacco, yielded similar concentrations of carbonyl compounds and their respective DNA adducts compared with the smoke of 1R6F reference cigarettes and the popular brand of cigarettes. We detected [13C]-isotopologues of DNA adducts such as 1,N6-etheno-dA, (8R/S)-3-(2'-deoxyribos-1-yl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10(3H)-one (γ-OH-Acr-dG), and (6S,8S and 6R,8R)-3-(2'-deoxyribos-1-yl)-5,6,7,8-tetrahydro-8-hydroxy-6-methylpyrimido[1,2-a]purine-10(3H)-one [(6S,8S)-γ-OH-Cro-dG and (6R,8R)-γ-OH-Cro-dG], proving that they have a direct source from tobacco smoke and providing important new insights regarding their mechanisms of formation. These unique results form the basis for further studies in cell culture and in cigarette smokers to establish how carcinogens in tobacco smoke cause DNA adduct formation.

Variability in addictive and carcinogenic potential of smokeless tobacco products marketed in Mumbai, India: a surveillance study

Background

India has the highest incidence worldwide of smokeless tobacco (SLT)-associated oral cancer, accounting for nearly 70% of all SLT users globally. Nicotine and tobacco-specific N-nitrosamines (TSNA) play critical roles in the addictive and carcinogenic potential, respectively, of SLT products. Our group has previously reported substantial variability in nicotine and TSNA levels across a small SLT product sample in India, calling for systematic surveillance. However, there is no information available on the current levels of these constituents in Indian SLT.

Methods

We analysed 321 samples representing 57 brands of eight popular types of manufactured SLT products purchased from five local markets in Mumbai, India between August, and September 2019. The sampling locations were Mumbai Central, Kurla, Thane, Vashi, and Airoli. Product pH, moisture content, total and unprotonated (biologically available) nicotine, and TSNA levels were measured at the Advanced Centre for Treatment, Research, and Education in Cancer (ACTREC) in Mumbai.

Findings

Total nicotine content ranged from 0.45 to 35.1 mg/g across products. The unprotonated nicotine fraction contributed 0.1-100% of the total nicotine content. The carcinogenic TSNA levels ranged 0.06-76 ug/g for N'-nitrosonornicotine (NNN), 0.02-19.2 ug/g for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and 0.01-6.51 ug/g for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). Consistent with our previous study, we observed substantial variations across different brands of the same product type.

Interpretation

This is the most extensive and the first within-country study to report brand-specific nicotine and TSNA levels in SLT products marketed in Mumbai, India. Our results show that levels of these constituents remain extremely variable across Indian SLT and are strikingly high in many products. Enhanced public education and continued efforts to reduce SLT use prevalence in India are critical for reducing the global burden of SLT-associated morbidity and mortality. Regulation of nicotine and TSNA levels in SLT products should be considered.

Funding

This work was supported by the National Institutes of Health (USA) grant R01-TW010651 and, in part, by grants R01-CA180880 and R50-CA211256. The LC-MS/MS analysis was supported in part by XII Plan project funding from the Department of Atomic Energy, Government of India.

Hydroponic Growth of [13C]-Labeled Tobacco for DNA Damage Studies in Cigarette Smokers

Cigarette smoking is the acknowledged major cause of cancers of the lung and oral cavity and is an established important risk factor for multiple other cancers. DNA addition products (DNA adducts) caused by cigarette smoking are critical factors in its mechanism of carcinogenesis. However, most DNA adducts detected to date in humans cannot be specifically ascribed to smoking but rather have multiple exogenous and endogenous sources. In the study reported here, we prepared [13C]-labeled tobacco to address this problem. We report for the first time the successful growth from seeds to flowering under hydroponic conditions of highly [13C]-labeled tobacco in a controlled 13CO2 environment. The standard growth procedure with optimized conditions is described in detail. The [13C]-enrichment rate was assessed by quantifying nicotine and sugars and their [13C]-isotopologues in this tobacco using high-resolution mass spectrometry, reaching >94% in the tobacco leaves. The [13C]-labeled leaves after curing will be used to make cigarettes, allowing investigation of the specific contributions of tobacco smoke carcinogens to identified DNA adducts in smokers.

Acute effects of charcoal filters and package color on cigarette perceptions and use behaviors: Results from a randomized pilot study examining Natural American Spirit "Sky"

INTRODUCTION

Charcoal-filtered cigarettes have been available for decades but have never held a major share of the U.S. cigarette market. This pilot study gathered initial behavioral data characterizing how "Sky"-a recently introduced charcoal-filtered cigarette variety that uses potentially misleading marketing features-is used and what impact its packaging color has on consumer perceptions.

METHODS

Forty adult daily non-menthol cigarettes users (52.5% male, 75.0% White, mean age = 46.1, 14.3 mean cigarettes/day) completed a single-session deception study utilizing a 2 ×2 mixed factorial design to manipulate cigarette filter condition (charcoal vs. non-charcoal) and pack color (light vs. dark). Participants smoked two cigarettes identical in appearance and packaging but differing in filter type (blinded and order counterbalanced) and completed pre- and post-cigarette CO samples and post-cigarette questionnaires.

RESULTS

Participants endorsed more favorable subjective ratings, puffed less of, held more correct beliefs about risks, and expressed greater intentions to use the charcoal (vs. non-charcoal)-filtered cigarette (p's <0.05). Pack color had few effects on outcomes; however, cigarettes in light vs. dark colored packs were rated as cleaner tasting (p <0.01). Neither filter condition nor pack color affected CO boost. There were no interaction effects on any outcomes.

CONCLUSIONS

Under blinded conditions, Sky charcoal-filtered cigarettes are initially appealing independent of their packaging color. Findings warrant further study of these effects on perceptions, behavior, and harm exposure after longer, open-label use periods. Findings may inform regulatory decisions regarding cigarette packaging and filter composition.

Heterogeneity of Harmful Constituent Profiles in Smokeless Tobacco Products from Five African Countries

Addictive, toxic, and carcinogenic constituents present in smokeless tobacco (SLT) products are responsible for the harmful effects associated with SLT use. There are limited data on levels of such constituents in SLT products used in Africa, a region with high prevalence of SLT use and the associated morbidity and mortality. Manufactured and custom-made SLT products were purchased from five African countries (South Africa, Uganda, Mauritania, Nigeria, and Zambia) using a standard approach for sample collection, labeling, and storage. Moisture content, pH, total and unprotonated (biologically available) nicotine, five tobacco-specific N-nitrosamines (TSNA), 10 polycyclic aromatic hydrocarbons (PAH), five metals and metalloids (As, Cd, Cr, Ni, and Pb), nitrate, and nitrite were analyzed. A total of 54 samples representing 15 varieties of manufactured SLT products and 13 varieties of custom-made SLT products were purchased and analyzed. In all samples, the total nicotine ranged from 1.6 to 20.5 mg/g product and unprotonated nicotine accounted for 5.3-99.6% of the total nicotine content. The sum of all five TSNA ranged from 1.6 to 100 μg/g product, with significant within-country variations observed across both the manufactured and custom-made varieties. Significant variations were also found for PAH, metals and metalloids, nitrates, and nitrites. This is the most comprehensive report on the chemical profiling of products from African countries. This is also the first study illustrating the variability of harmful constituents within the same types and brands of African SLT. Our findings emphasize the need for consumer education and interventions to reduce SLT use in Africa. The data reported here can be useful to regulators in considering measures to prevent the occurrence of high levels of known toxicants and carcinogens in manufactured products.

High-Field Asymmetric Waveform Ion Mobility Spectrometry Analysis of Carcinogenic Aromatic Amines in Tobacco Smoke with an Orbitrap Tribrid Mass Spectrometer

Smoking is a risk factor for bladder cancer (BC), although the specific chemicals responsible for BC remain uncertain. Considerable research has focused on aromatic amines (AAs), including o-toluidine (o-tol), o-anisidine (o-anis), 2-naphthylamine (2-NA), and 4-aminobiphenyl (4-ABP), which are linked to human BC based on elevated BC incidence in occupationally exposed factory workers. These AAs arise at nanogram levels per combusted cigarette. The unambiguous identification of AAs, particularly low-molecular-weight monocyclic AAs in tobacco smoke extracts, by liquid chromatography-mass spectrometry (LC-MS) is challenging due to their poor performance on reversed-phase columns and co-elution with isobaric interferences from the complex tobacco smoke matrix. We employed a tandem liquid-liquid and solid-phase extraction method to isolate AAs from the basic fraction of tobacco smoke condensate (TSC) and utilized high-field asymmetric waveform ion mobility spectrometry (FAIMS) coupled to high-resolution accurate mass (HRAM) Orbitrap LC-MS2 to assay AAs in TSC. The employment of FAIMS greatly reduced sample complexity by removing precursor co-isolation interfering species at the MS1 scan stage, resulting in dramatically improved signal-to-noise of the precursor ions and cleaner, high-quality MS2 spectra for unambiguous identification and quantification of AAs in TSC. We demonstrate the power of LC/FAIMS/MS2 by characterizing and quantifying two low-molecular-weight carcinogenic AAs, o-tol and o-anis, in TSC, using stable isotopically labeled internal standards. These results demonstrate the power of FAIMS in trace-level analyses of AA carcinogens in the complex tobacco smoke matrix.

Diet as a Source of Acrolein: Molecular Basis of Aldehyde Biological Activity in Diabetes and Digestive System Diseases

Acrolein, a highly reactive α,β-unsaturated aldehyde, is a compound involved in the pathogenesis of many diseases, including neurodegenerative diseases, cardiovascular and respiratory diseases, diabetes mellitus, and the development of cancers of various origins. In addition to environmental pollution (e.g., from car exhaust fumes) and tobacco smoke, a serious source of acrolein is our daily diet and improper thermal processing of animal and vegetable fats, carbohydrates, and amino acids. Dietary intake is one of the main routes of human exposure to acrolein, which is a major public health concern. This review focuses on the molecular mechanisms of acrolein activity in the context of its involvement in the pathogenesis of diseases related to the digestive system, including diabetes, alcoholic liver disease, and intestinal cancer.

The Tobacco Smoke Component, Acrolein, as a Major Culprit in Lung Diseases and Respiratory Cancers: Molecular Mechanisms of Acrolein Cytotoxic Activity

Acrolein, a highly reactive unsaturated aldehyde, is a ubiquitous environmental pollutant that seriously threatens human health and life. Due to its high reactivity, cytotoxicity and genotoxicity, acrolein is involved in the development of several diseases, including multiple sclerosis, neurodegenerative diseases such as Alzheimer’s disease, cardiovascular and respiratory diseases, diabetes mellitus and even the development of cancer. Traditional tobacco smokers and e-cigarette users are particularly exposed to the harmful effects of acrolein. High concentrations of acrolein have been found in both mainstream and side-stream tobacco smoke. Acrolein is considered one of cigarette smoke’s most toxic and harmful components. Chronic exposure to acrolein through cigarette smoke has been linked to the development of asthma, acute lung injury, chronic obstructive pulmonary disease (COPD) and even respiratory cancers. This review addresses the current state of knowledge on the pathological molecular mechanisms of acrolein in the induction, course and development of lung diseases and cancers in smokers.

DNA Damage and Oxidative Stress of Tobacco Smoke Condensate in Human Bladder Epithelial Cells

Smoking is a major risk factor for bladder cancer (BC), with up to 50% of BC cases being attributed to smoking. There are 70 known carcinogens in tobacco smoke; however, the principal chemicals responsible for BC remain uncertain. The aromatic amines 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA) are implicated in BC pathogenesis of smokers on the basis of the elevated BC risk in factory workers exposed to these chemicals. However, 4-ABP and 2-NA only occur at several nanograms per cigarette and may be insufficient to induce BC. In contrast, other genotoxicants, including acrolein, occur at 1000-fold or higher levels in tobacco smoke. There is limited data on the toxicological effects of tobacco smoke in human bladder cells. We have assessed the cytotoxicity, oxidative stress, and DNA damage of tobacco smoke condensate (TSC) in human RT4 bladder cells. TSC was fractionated by liquid-liquid extraction into an acid-neutral fraction (NF), containing polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, phenols, and aldehydes, and a basic fraction (BF) containing aromatic amines, heterocyclic aromatic amines, and N-nitroso compounds. The TSC and NF induced a time- and concentration-dependent cytotoxicity associated with oxidative stress, lipid peroxide formation, glutathione (GSH) depletion, and apurinic/apyrimidinic (AP) site formation, while the BF showed weak effects. LC/MS-based metabolomic approaches showed that TSC and NF altered GSH biosynthesis pathways and induced more than 40 GSH conjugates. GSH conjugates of several hydroquinones were among the most abundant conjugates. RT4 cell treatment with synthetic hydroquinones and cresol mixtures at levels present in tobacco smoke accounted for most of the TSC-induced cytotoxicity and the AP sites formed. GSH conjugates of acrolein, methyl vinyl ketone, and crotonaldehyde levels also increased owing to TSC-induced oxidative stress. Thus, TSC is a potent toxicant and DNA-damaging agent, inducing deleterious effects in human bladder cells at concentrations of <1% of a cigarette in cell culture media.

Carcinogenic components of tobacco and tobacco smoke: A 2022 update

Tobacco and tobacco smoke contain a complex mixture of over 9500 chemical compounds, many of which have been recognized as hazardous to human health by regulatory agencies. In 2012, the U.S. Food and Drug Administration established a list of harmful and potentially harmful constituents in unburned tobacco and tobacco smoke, 79 of which are considered as carcinogens. Over the past 10 years, with advancing analytical technology, significant amounts of new data have been published, increasing our understanding of levels of carcinogens in tobacco products. The International Agency for Research on Cancer (IARC) has released 35 monographs since 2012, with an increasing number of compounds in unburned tobacco and tobacco smoke classified as carcinogens. In this paper, we provide an updated list of IARC-classified carcinogens in unburned tobacco and tobacco mainstream smoke. A total of 83 carcinogens has been identified - 37 in unburned tobacco and 80 in tobacco smoke - with their occurrence levels reported since 2012. No clear decreasing trends were observed for any of these carcinogens in recent years. Surveillance of the levels of tobacco carcinogens as well as regulatory actions are needed to ensure control of their levels so that potential reduced risks of cancer and other diseases may be achieved.

Cigarette Smoke Extract, but Not Electronic Cigarette Aerosol Extract, Inhibits Monoamine Oxidase in vitro and Produces Greater Acute Aversive/Anhedonic Effects Than Nicotine Alone on Intracranial Self-Stimulation in Rats

Conventional tobacco cigarettes appear to have greater abuse liability than non-combusted products such as electronic cigarettes (ECs) and nicotine replacement therapy (NRT). This may be due to the higher levels of behaviorally active non-nicotine constituents [e.g., monoamine oxidase (MAO) inhibitors such as β-carbolines] in cigarette smoke (CS) compared to non-combusted products. To evaluate this hypothesis, the current studies compared the relative abuse liability of CS and EC aerosol extracts containing nicotine and a range of non-nicotine constituents to that of nicotine alone (NRT analog) using intracranial self-stimulation (ICSS) in rats. Effects of formulations on brain MAO activity in vitro and ex vivo were also studied to evaluate the potential role of MAO inhibition in the ICSS study. CS extract contained higher levels of several behaviorally active non-nicotine constituents (e.g., the β-carbolines norharmane and harmane) than EC extract. Nicotine alone reduced ICSS thresholds at a moderate nicotine dose, suggesting a reinforcement-enhancing effect that may promote abuse liability, and elevated ICSS thresholds at a high nicotine dose, suggesting an aversive/anhedonic effect that may limit abuse liability. CS extract elevated ICSS thresholds to a greater degree than nicotine alone at high nicotine doses. Effects of EC extract on ICSS did not differ from those of nicotine alone. Finally, CS extract significantly inhibited MAO-A and MAO-B activity in vitro, whereas EC extract and nicotine alone did not. None of the formulations inhibited MAO measured ex vivo. These findings indicate greater acute aversive/anhedonic effects for CS extract compared to nicotine alone, suggesting lower abuse liability. Although confirmation of our findings using other dosing regimens, preclinical addiction models, and tobacco product extracts is needed, these findings suggest that the centrally-mediated effects of MAO inhibitors and other non-nicotine constituents may not account for the greater abuse liability of cigarettes compared to non-combusted products. Nonetheless, identifying the specific constituent(s) mediating the effects of CS extracts in this study could help clarify mechanisms mediating tobacco addiction and inform FDA product standards.

Carbonyl Compounds in Mainstream Smoke of Hemp Cigarettes

Introduction: CBD is a major phytocannabinoid in hemp (Cannabis sativa containing less than 0.3% THC). Hemp cigarettes are a combustible form of hemp consisting of dried and smokable flowers, which represent 2% of the overall CBD market, and the market is expected to grow. Combustion and pyrolysis of organic material are associated with the production of carbonyl compounds, which are known toxicants and are associated with adverse health outcomes. Concentrations of carbonyl compounds in mainstream hemp cigarette smoke are unknown. Materials and Methods: We analyzed and compared carbonyl concentrations in the mainstream smoke produced by a hemp cigarette (Brand B), a premium hemp cigarette (Brand A), Marlboro Red tobacco cigarette, and a research reference tobacco cigarette using high-performance liquid chromatography. We measured carbonyl concentrations in μg per puff and mg per cigarette. Carbonyls investigated were formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, crotonaldehyde, 2-butanone, and butyraldehyde. Significance was determined using Tukey's test. Results: We observed that Brand B had significantly higher butyraldehyde than any cigarette. No significant differences were observed in crotonaldehyde concentration in the cigarettes. For the remaining carbonyls, Brand A had consistently lower concentrations in mainstream smoke than tobacco cigarettes. Hemp cigarettes emit carbonyls in a lower concentration in μg/puff than tobacco cigarettes, but the magnitude of significance generally decreases when normalized to mg/cigarette. Conclusions: Smoke from hemp cigarettes contains carbonyls at biologically significant concentrations. Opportunities may exist to reduce carbonyl production in these products, and identified potential risks must be considered when balancing the harms and benefits of hemp cigarettes when used for therapeutic purposes.

Adolescents' Health Perceptions of Natural American Spirit's On-the-Pack Eco-Friendly Campaign

PURPOSE

Natural American Spirit (NAS) cigarettes, which have recently grown in popularity, are marketed as eco-friendly and natural. The present study examined whether NAS's on-the-pack messaging influences adolescents' health perceptions of the brand.

METHODS

In a mixed-factor design, adolescent participants (N = 1,003, ages 13-17, 75% female) were randomized to one of the six exposure conditions. All viewed images of an NAS and a Pall Mall (comparison brand) cigarette pack, but differed in pack color (blue, green, or gold/orange) and brand viewed first. Perceptions of pack logos, addictiveness, harms to the smoker, others, and the environment were assessed directly after viewing pack images for each brand.

RESULTS

Adolescents who perceived NAS as more pro-environment tended to perceive NAS cigarettes to be less addictive, r = -.19, p < .01. NAS cigarettes also were perceived as less addictive and better for the environment than Pall Mall. Most (90%) participants provided nature-friendly words (e.g., environment, recycle) when asked to describe logos on the NAS packs. In adjusted models, relative to Pall Mall, NAS was perceived as healthier for smokers, healthier for smokers' family and friends, and safer for the environment. Findings did not differ by pack color and ever tobacco use.

CONCLUSIONS

Adolescents perceived a health advantage for NAS cigarettes with its on-the-pack, eco-friendly and pro-health marketing. The findings are consistent with prior research with adults. Given the accumulating evidence of consumer misperceptions, eco-friendly messaging on cigarettes is a public health concern that warrants further consideration for regulatory intervention.

Popularity of natural American Spirit cigarettes is greater in U.S. cities with lower smoking prevalence

BACKGROUND

Often perceived as a safer smoke, Natural American Spirit (NAS) may find particular appeal in communities with strong non-smoking norms. We hypothesized NAS would be more popular in cities with lower smoking prevalence, with the pattern unique to NAS. We tested household income, cigarette taxes, and young adult population as alternative correlates and examined brand specificity, relative to Marlboro and Pall Mall.

METHODS

Using proprietary, city-specific sales estimates obtained from Nielsen for 30 U.S. cities over one year (9/7/18-9/9/19), we computed cigarette sales volume as standard pack units per 10,000 adult smokers for NAS and Marlboro and Pall Mall. Linear regression models examined associations between city-level sales volume and adult smoking prevalence, median household income, the sum of state/local cigarette excise taxes, and young adult population.

RESULTS

NAS sales volume averaged 44,785 packs per 10,000 adult smokers (SD = 47,676). Across 30 cities, adult smoking prevalence averaged 18.0% (SD = 4.5%), median household income averaged $53,677 (SD = $14,825), cigarette excise tax averaged $2.55 (SD = $1.63), and young adult population averaged 10.6% (SD = 2.2%). NAS sales volume was greater in cities with lower adult smoking prevalence (β = -0.39, 95% CI[-0.74, -0.03], p = 0.034), a pattern that was not observed for Marlboro or Pall Mall (ps > 0.356). Marlboro (β = -0.40, 95% CI[-0.76, -0.05], p = 0.027) and Pall Mall (β = -0.48, 95% CI[-0.82, -0.14], p = 0.008) sales volumes were higher in cities where cigarette excise taxes were lower, a pattern not observed for NAS (p = 0.224).

CONCLUSION

NAS appears to be more popular in cities with lower smoking prevalence and may deter efforts to further decrease prevalence.