Search Results (75)

The use of sweeteners in e-cigarette liquids has become increasingly common, aiming to enhance the sensory appeal of vaping products. Compounds like aspartame, saccharin, and sucralose are added to provide a sweet taste without any calories, especially in flavored e-liquids popular among younger users. However, recent studies suggest that these additives may pose significant health risks when vaporized and inhaled. Sucralose, in particular, can break down into potentially harmful chlorinated by-products at high temperatures typical of vaping devices. Moreover, there is growing concern about the synergistic effects of sweeteners like sucralose, one sweetener with another and when combined with other e-liquid components. It has been observed that the presence of sucralose may amplify oxidative stress; genotoxicity, including mutations; and overall toxicity, along with environmental impact. This is not limited to nicotine- and smoke-related harm, as it may strengthen the toxic effect of the substances used in e-liquids that are not present in traditional cigarettes. The combined exposure to these heated compounds can intensify cytotoxicity, potentially increasing the risk of respiratory, cardiovascular, and neurological effects over time. While marketed as safer alternatives to tobacco, e-cigarettes containing sweeteners like sucralose may introduce new and poorly understood toxicological hazards that deserve urgent regulatory attention. Full article

The use of electronic cigarettes has increased in the U.S. with menthol and mint flavors showing notably higher sales. While research on the bacterial microbiome of traditional tobacco products is growing, particularly regarding menthol and nicotine effects, data regarding potential microbial contaminants within electronic liquids (e-liquids) remain limited. Additionally, the potential antibacterial properties of e-liquids remain sparse. To address these gaps, we evaluated the prevalence of viable bacteria in e-liquids; characterized their antimicrobial susceptibility patterns; and tested the antibacterial activity of the e-liquids. Two e-liquid flavors (menthol and non-menthol) across three different nicotine concentrations (0, 6 and 12 mg/mL) were tested using culture-based methods and Sanger sequencing. Antimicrobial susceptibility testing and e-liquid antibacterial activity assays were performed using the Kirby Bauer disc diffusion method. The majority of the isolates (63.15%) were identified as Pseudomonas aeruginosa and Bacillus spp. (B. pumilus, B. megaterium and B. cereus). Notably, P. aeruginosa and P. fluorescens isolates exhibited multidrug resistance against penicillin, tetracyclines, and phenicols. The e-liquids also demonstrated antimicrobial activity, inhibiting the growth of B. cereus, P. aeruginosa, and Staphylococcus aureus, with greater inhibition of P. aeruginosa growth at higher (12 mg/mL) compared to lower (0 mg/mL) nicotine concentrations across the menthol-flavored samples. These findings offer preliminary evidence of viable, multidrug-resistant bacteria and antibacterial properties in e-liquids, underscoring potential public health concerns regarding user exposure risks and microbial interactions, and emphasizing the need for continued surveillance of microbial safety in electronic cigarette products. Full article

Litchi (Litchi chinensis Sonn.) is a kind of evergreen fruit tree with good flavor and taste which has high economic value. Sufficiently low temperature in winter is essential for the successful flower formation of litchi. Therefore, in the context of global warming, litchi often experiences unstable flower formation, ultimately resulting in a decrease in litchi production. Our previous research has highlighted the pivotal role of the LcFT1 gene in regulating the flower formation of litchi and identified two AP1 homologous genes associated with LcFT1 (named LcAP1-1 and LcAP1-2) based on RNA-Seq and weight gene co-expression network analysis (WGCNA). In this study, the functions of the two AP1 homologous genes in regulating flowering time were investigated. Result showed that LcAP1-1 and LcAP1-2 were expressed in all litchi tissues. LcAP1-1 was more highly expressed in mature leaves compared to other tissues, while the LcAP1-2 has the highest expression level in flower buds. Both of them exhibited upregulation in the terminal bud of litchi under low temperature. The expression of LcAP1-1 and LcAP1-2 was highly correlated with the initiation of flower buds and the development of flower organs. They increased gradually during the floral initiation but decreased gradually during flower bud development. The transgenic tobacco of LcAP1-2 flowered about 55 days earlier than wild-type, while tobacco overexpressing the LcAP1-1 gene had no significant changes in flowering time compared to the wild-type. These results indicate that the two genes have divergent regulatory functions, and that the LcAP1-2 gene may be involved in the regulation of flower transformation and flower organ development in litchi. Our research will further reveal the molecular regulatory mechanisms of flower formation in litchi and will also provide theoretical guidance for the molecular breeding of litchi. Full article

Once marketed as smoking cessation tools, e-cigarettes are used by adolescents mainly for entertainment, driven by aggressive marketing, appealing flavors, and safer alternatives to smoking. This study analyzes data from the National Youth Tobacco Survey (NYTS) to explore trends in adolescent perceptions and usage patterns of e-cigarettes from 2011 to 2023, focusing on their dual roles as cessation aids and recreational products. Cross-sectional data from the NYTS over four years (2011: N = 18,866; 2015: N = 17,711; 2019: N = 19,018; 2023: N = 22,069) formed the foundation of this study. This study investigated demographic trends, usage frequency, initial and future use patterns, and quitting behavior. Descriptive statistics and latent class analysis (LCA) were employed to examine adolescent e-cigarette use patterns, with statistical significance determined at p < 0.05. The reasons for using e-cigarettes have changed significantly over the years because of family or friends. In all years (2015–2023), use for smoking cessation dropped significantly (2.33% in 2023 vs. 6.95% in 2015). In 2023, 38% wanted to quit using e-cigarettes within 30 days, and 25% attempted to quit at least 10 times. Flavored e-cigarette users were more than twice as likely to consider quitting compared to those not interested in flavors (OR = 2.64). Our findings highlight a significant decrease in the use of e-cigarettes for cessation, with a corresponding increase in recreational use over time. These trends emphasize the urgency of implementing interventions to mitigate nicotine addiction and its associated health risks among adolescents. Adolescent e-cigarette use has transitioned from being primarily driven by cessation efforts to recreational purposes, largely influenced by appealing flavors and social factors such as peer influence, showing the need for stricter marketing regulations and targeted educational campaigns. Full article

Tobacco control policies have aimed to reduce the global prevalence of smoking. Unfortunately, the recent survey data shows that about 24% of Europeans still smoke. Although combustible cigarettes remain the most used tobacco product, the tendency made evident in the prevalence of smoking-alternative nicotine-containing products increases. Studies that can objectively assess the long-term health effects of the latter products are lacking, so assessing toxic substances associated with smoking-alternative products and comparing them to substances from combustible cigarettes could inform future public health efforts. The manufacturers of these alternative products claim that the use of alternatives to combustible cigarettes reduces exposure to toxic compounds, but the reality is unclear. This study compares the concentrations of toxic substances in generated aerosols and performs calculations based on mainstream cigarette smoke and aerosols from smoking-alternative products. It summarizes the amounts of harmful and potentially harmful constituents per single puff. Alternative smoking products are undoubtedly harmful to non-smokers. Still, based on the analysis of the latest independent studies’ empirical data, the concentrations of inhaled HPHCs using heated tobacco products or e-cigarettes are reduced up to 91–98%, respectively; therefore, for those who cannot quit, these could provide a less harmful alternative. However, more well-designed studies of alternative product emissions are needed, including an analysis of the compounds that are not present in conventional tobacco products (e.g., thermal degradation products of propylene glycol, glycerol, or flavorings) to evaluate possible future health effects objectively. Full article

Electronic cigarettes (ECIGs) are widely used but their effects on the immune system need to be further investigated. Macrophages are white blood cells central to the immune response. Using THP-1-derived M0 macrophages, this study aims to determine the effects of ECIG liquids (E-liquids) on the polarization of M0 to the pro-inflammatory M1 macrophage subtype. THP-1 cells were cultured and differentiated to M0 macrophages using RPMI media. E-liquids ± cinnamon, menthol, strawberry and tobacco flavors were added to cell cultures at 1% (v/v) during polarization with lipopolysaccharides and interferon γ for 24 to 72 h. Morphology, viability, gene expression and cytokine production were measured using light microscopy, the LDH cytotoxicity assay, qPCR and ELISA, respectively. The results show that cells present little to no LDH activity under any treatments. In addition, cinnamon-flavored E-liquid severely affects morphology (i.e., abolishing pseudopodia formation), gene expression of all genes tested, and cytokine production. Other E-liquid flavors also affect some of these parameters, but to a lesser extent. Our data suggest that E-liquids can affect the polarization from M0 to M1, thus affecting the immune response in ECIG-exposed tissues such as the mucosa in the oral cavity and airways, ultimately mitigating the health status. Full article

Alpha-cembratriene-4,6-diol (α-CBT-diol) is a complex diterpenoid primarily found in Solanaceae (i.e., tobacco leaves), Pinaceae, and marine corals. Due to its intricate chemical structure, it serves as a precursor for several aroma compounds, including farnesal. Farnesal and its derivatives have applications across various fields, such as the fragrance and flavor industry, pharmaceuticals, agriculture, and cosmetics. In this study, Stenotrophomonas maltophilia H3-1, a strain capable of efficiently biodegrading α-CBT-diol into farnesal, was isolated from soil and identified through 16S rDNA sequence analysis. S. maltophilia H3-1 biodegraded 93.3% of α-CBT-diol (300 mg/L) within 36 h when grown under optimized culture conditions, including a temperature of 40 °C, pH of 8, 2 g/L maltose, and 2 g/L ammonium sulfate. Theoretically, this strain can produce 201 mg/L of farnesal during the biotransformation of α-CBT-diol. The putative α-CBT-diol bioconversion pathway expressed in S. maltophilia H3-1 is also proposed. This is the first study to report the bioconversion of α-CBT-diol into the high-value compound farnesal using a novel S. maltophilia H3-1 strain. It highlights that other compounds found in tobacco can also be bioconverted into valuable products. Full article

Background: Electronic cigarettes (ECIGs) have grown in popularity, particularly among adolescents and young adults. Flavored ECIG-liquids (E-liquids) are aerosolized by these ECIGs and inhaled into the respiratory system. Several studies have shown detrimental effects of E-liquids in airway tissues, revealing that flavoring agents may be the most irritating component. However, research on the effects of E-liquids on biological processes of the oral cavity, which is the first site of aerosol contact, is limited. Hence, this study focuses on the effects of E-liquid flavors on oral epithelial cells using the OKF6/TERT-2 cell line model. Methodology: E-liquid was prepared with and without flavors (tobacco, menthol, cinnamon, and strawberry). OKF6/TERT-2 oral epithelial cells, cultured at 37 °C and 5% CO₂, were exposed to 1% E-liquid ± flavors for 24 h. Outcomes determined include cell morphology, media pH, wound healing capability, oxidative stress, expression of mucin and tight junction genes, glycoprotein release, and levels of inflammatory cytokines (TNFα, IL-6, and IL-8). Results: Exposure to 1% flavored E-liquids negatively affect cellular confluency, adherence, and morphology. E-liquids ± flavors, particularly cinnamon, increase oxidative stress and production of IL-8, curtail wound healing recovery, and decrease glycoprotein release. Gene expression of muc5b is downregulated after exposure to E-liquids. In contrast, E-liquids upregulate occludin and claudin-1. Conclusions: This study suggests that ECIG use is not without risk. Flavored E-liquids, particularly cinnamon, result in pathophysiological responses of OKF6/TERT-2 cells. The dysregulation of inflammatory responses and cellular biology induced by E-liquids may contribute to various oral pathologies. Full article

Menthol, a cyclic monoterpene alcohol commonly derived from mint essential oils, is widely utilized across the pharmaceutical, cosmetic, and personal care industries due to its cooling, analgesic, and aromatic properties. This study presents a comprehensive patent landscape analysis of organic menthol crystals and their derivatives, with a focus on identifying current trends and emerging applications. Patent data were retrieved from The Lens and Google Patents, and 23,515 relevant patents were analyzed using international patent classification codes. The results revealed significant applications in pharmaceuticals, personal care, and drug delivery systems, with notable innovations in controlled-release formulations, cancer treatments, and pain relief products. Emerging trends include the combination of menthol with other natural compounds, advances in microencapsulation for controlled drug delivery, and its use as flavor enhancement in the tobacco industry. The United States leads in menthol-related patents, followed by China and the European Union. This analysis provides valuable insights into the future of menthol applications, suggesting that its role in therapeutic and cosmetic industries will continue to grow, driven by technological advancements and regulatory factors. Full article

Background: There is limited evidence on how the United States Food and Drug Administration’s (FDA) proposed ban on menthol cigarettes and flavored cigars will impact individuals with mood disorders who smoke menthol cigarettes. This study aimed to evaluate how individuals with mood disorders who smoke menthol cigarettes might respond to a hypothetical ban on menthol cigarettes, explore the reasons for their current use, and examine how these reasons are associated with participants’ characteristics. Methods: Study data were collected at baseline from adults (18+ years) with mood disorders who participated in a randomized controlled trial evaluating the impact of gradual nicotine reduction. Participants were individuals who smoked and had no plan to quit in the next six months. They reported demographics and tobacco consumption patterns, interest in quitting, and responded to a hypothetical question on a potential ban on menthol cigarettes. The question asked participants which actions they would most likely take if menthol-flavored cigarettes were banned. Means and frequencies were used to describe the sample. Logistic regression was used to determine factors associated with each reason for menthol use (less harmful, better flavor, less harsh on the throat, and less harsh on the chest). Results: Participants (n = 77) were an average age of 42.5 (SD 12.5) years, 61% (n = 47) were female, 68.8% (n = 53) identified as White, and 5.2% (n = 4) identified as Hispanic. On average, participants reported currently smoking 18.1 (SD 9.9) cigarettes per day and had smoked for 23.9 (SD 13.6) years. About 58.4% of participants (n = 45) expressed their intention to switch to non-menthol cigarettes, 19.5% (n = 15) intended to transition to a different type of tobacco product, and 22.1% (n = 17) intended to quit smoking entirely without substitution. The most endorsed reason for using menthol cigarettes was better flavor (89.6%, n = 69/77), followed by less harshness on the throat (41.3%, n = 31/75) and chest (40%, n = 30/75), and the belief that they were less harmful than non-menthol cigarettes (24%, n = 18/75). Older age was associated with the belief that menthol cigarettes were less harmful (OR = 1.06; p = 0.02). Conclusion: Among individuals with mood disorders and who smoke menthol cigarettes and have no plans to quit smoking, 22.1% may try to quit smoking if a menthol ban is implemented, while the majority (58.4%) stated that they would switch to non-menthol cigarettes. As the reasons for using menthol cigarettes included perceived lower harm, there is a need for targeted public awareness campaigns to correct misconceptions about the harms of menthol cigarettes. Full article

New-generation disposable e-cigarettes have become increasingly popular among young adults in the USA since the FDA’s partial flavor ban. This study aims to examine longitudinal changes in health risks among young adults who adopted these novel products, as well as the health effects of device types beyond the effects of other important e-cigarette characteristics. This study recruited e-cigarette users via voluntary response sampling from three college campuses in the USA to respond to four-wave online surveys conducted in four consecutive semesters. Among the participants who adopted disposables during the study, their health risks (dependence symptoms, respiratory symptoms, combustible tobacco use) and e-cigarette consumption characteristics (use frequency, nicotine concentration and flavors) before and after the adoption were compared using paired-sample t- or McNemar’s tests. Generalized linear mixed models with a random intercept were conducted on data from the entire sample to investigate the effects of device type (tank, cartridge/pod, disposable) on health risks, controlling for other e-cigarette consumption characteristics. The study sample of 650 e-cigarette users were, on average, 20 years old, with 49% being male, 70% being White, and 13% being Hispanic. Adopting disposables may increase secondary dependence motives (t = 2.42, p < 0.05) and the use of higher levels of nicotine concentration (t = 2.09, p < 0.05) and sweet flavors (x² = 22.53, p < 0.05) but decrease the number of times of vaping per day (t = −2.18, p < 0.05) and the use of menthol flavors (x² = 4.57, p < 0.05). Tank use is associated with a higher level of primary dependence motives (b = 0.1998, p < 0.05) and a greater odds of using combustible tobacco (b = 0.4772, p < 0.05). Although disposable use is not associated with the likelihood of using combustible tobacco, it is associated with higher levels of both primary (b = 0.2158, p < 0.05) and secondary (b = 0.2533, p < 0.05) dependence motives. It is not the device type, but rather the frequency of vaping, that affects respiratory symptoms (b = 0.0602, p < 0.05). The findings indicate that when young adults switch to disposables, their e-cigarette dependence and use of sweet-flavored e-liquids increase. Even after controlling for use frequency, nicotine concentration and flavors, using disposables is related to not only instrumental motives that are influenced by psychological and environmental contexts but also heavy, automatic use that can operate without environmental cues. Given the health risks associated with disposable e-cigarettes, more comprehensive tobacco product regulations that consider the impact of device types may be needed. Full article

This study investigates the application of an eNose (electrochemical sensory array) device as a rapid and cost-effective screening tool to detect increasingly prevalent counterfeit electronic cigarettes, and those to which potentially hazardous excipients such as vitamin E acetate (VEA) have been added, without the need to generate and test the aerosol such products are intended to emit. A portable, in-field screening tool would also allow government officials to swiftly identify adulterated electronic cigarette e-liquids containing illicit flavorings such as menthol. Our approach involved developing canonical discriminant analysis (CDA) models to differentiate formulation components, including e-liquid bases and nicotine, which the eNose accurately identified. Additionally, models were created using e-liquid bases adulterated with menthol and VEA. The eNose and CDA model correctly identified menthol-containing e-liquids in all instances but were only able to identify VEA in 66.6% of cases. To demonstrate the applicability of this model to a commercial product, a Virginia Tobacco JUUL product was adulterated with menthol and VEA. A CDA model was constructed and, when tested against the prediction set, it was able to identify samples adulterated with menthol 91.6% of the time and those containing VEA in 75% of attempts. To test the ability of this approach to distinguish commercial e-liquid brands, a model using six commercial products was generated and tested against randomized samples on the same day as model creation. The CDA model had a cross-validation of 91.7%. When randomized samples were presented to the model on different days, cross-validation fell to 41.7%, suggesting that interday variability was problematic. However, a subsequently developed support vector machine (SVM) identification algorithm was deployed, increasing the cross-validation to 84.7%. A prediction set was challenged against this model, yielding an accuracy of 94.4%. Altered Elf Bar and Hyde IQ formulations were used to simulate counterfeit products, and in all cases, the brand identification model did not classify these samples as their reference product. This study demonstrates the eNose’s capability to distinguish between various odors emitted from e-liquids, highlighting its potential to identify counterfeit and adulterated products in the field without the need to generate and test the aerosol emitted from an electronic cigarette. Full article

Heated Tobacco Products (HTPs) purport to reduce exposure to tobacco-related toxicants compared to combustible cigarettes. This cross-sectional study examined the content of nicotine, two humectants (propylene glycol (PG) and vegetable glycerin (VG)), and four tobacco-specific nitrosamines (TSNAs: NNN, NNK, NAT, and NAB) in the tobacco filler of a popular HTP brand (IQOS). Non-menthol and menthol IQOS sticks were purchased from nine countries between 2017 and 2020 and were classified into two versions (“Bold” and “Light”) using Philip Morris’s flavor descriptors. The average nicotine concentration was 4.7 ± 0.5 mg/stick, and the highest nicotine concentration was found in products from Japan (5.1 ± 0.2 mg/stick). VG was the dominant humectant found in all sticks, with an average concentration of (31.5 ± 2.3 mg/stick). NNN, NNK, and NAT were substantially higher in the “Bold” sticks than the “Light” sticks. Significant differences between countries for TSNAs were also observed: the NAT and NAB contents were the highest in the “Light” products from Canada (192.5 ± 24.1 and 22.9 ± 1.0 ng/stick, respectively); the NNK concentration was the highest in the “Bold” products from Poland (64.8 ± 7.9 ng/stick); and the highest NNN concentrations were observed in the “Bold” products from South Africa (488.9 ± 26.7 ng/stick). As NNN and NNK are known human carcinogens, and as humectants like PG and VG can degrade into toxic carbonyl compounds upon heating, monitoring the concentration of these chemicals in HTPs is important for protecting users’ health and ensuring compliance with regulations. Full article

Tobacco smoking remains one of the leading causes of premature death worldwide. Electronic Nicotine Delivery Systems (ENDSs) are proposed as a tool for smoking cessation. In the last few years, a growing number of different types of ENDSs were launched onto the market. Despite the manufacturing differences, ENDSs can be classified as “liquid e-cigarettes” (e-cigs) equipped with an atomizer that vaporizes a liquid composed of vegetable glycerin (VG), polypropylene glycol (PG), and nicotine, with the possible addition of flavorings; otherwise, the “heated tobacco products” (HTPs) heat tobacco sticks through contact with an electronic heating metal element. The presence of some metals in the heating systems, as well as in solder joints, involves the possibility that heavy metal ions can move from these components to the liquid, or they can be adsorbed into the tobacco stick from the heating blade in the case of HTPs. Recent evidence has indicated the presence of heavy metals in the refill liquids and in the mainstream such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb). The present review discusses the toxicological aspects associated with the exposition of heavy metals by consumption from ENDSs, focusing on metal carcinogenesis risk. Full article

Assessment of in vitro cytotoxicity is an important component of tobacco product toxicological evaluations. However, current methods of regulatory testing involve exposing monolayer cell cultures to various preparations of aerosols from cigarettes or other emerging products such as electronic nicotine delivery systems (ENDS), which are not representative of human exposure. In the present study, a whole aerosol (WA) system was used to expose lung epithelial cultures (2D and 3D) to determine the potential of six Vuse Alto ENDS products that varied in nicotine content (1.8%, 2.4%, and 5%) and flavors (Golden Tobacco, Rich Tobacco, Menthol, and Mixed Berry), along with a marketed ENDS and a marked cigarette comparator to induce cytotoxicity and oxidative stress. The WA from the Vuse Alto ENDS products was not cytotoxic in the NRU and MTT assays, nor did it activate the Nrf2 reporter gene, a marker of oxidative stress. In summary, Vuse Alto ENDS products did not induce cytotoxic or oxidative stress responses in the in vitro models. The WA exposures used in the 3D in vitro models described herein may be better suited than 2D models for the determination of cytotoxicity and other in vitro functional endpoints and represent alternative models for regulatory evaluation of tobacco products. Full article