Effects of Ingredients on Cigarette Smoke Composition and Biological Activity: A Literature Overview

Paschke, Thilo; Scherer, Gerhard; Heller, Wolf-Dieter

doi:10.2478/cttr-2013-0736

Cited by 41 publications

(46 citation statements)

References 70 publications

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“…The evidence includes chemical data, e.g., smoke composition and pyrolysates, biological data on inhalation, skin painting, and genotoxicity. In more recent detailed assessments of reported chemical and biological properties for the MSSs from cigarettes fabricated with tobacco with or without one or more additives, PASCHKE et al (81) and RODGMAN (16) reached a similar conclusion: No significant increase in the biological activity of tobacco was reported from cigarettes containing added ingredients. Information that flavorful components in tobacco did not enhance the PAH level in MSS was provided by the study of the organic solvent extraction of tobacco.…”

Section: The Assertion Of the Generation Of Toxicants From Additivessupporting

confidence: 48%

Toxic Chemicals in Cigarette Mainstream Smoke - Hazard and Hoopla

Rodgman¹,

Green²

2003

Beiträge Zur Tabakforschung International/Contributions to Tobacco Research

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These are curious times. The Canadian government has passed legislation that requires cigarette manufacturers to routinely test and publish the amounts of 44 toxic substances in cigarette mainstream smoke (MSS). Following in the footsteps of their northern neighbor, various US legislators and regulators are considering modifications to their cigarette testing and reporting programs that will also list toxicants in MSS. Across the Atlantic Ocean, the European Commission has passed a directive that may also follow the North American lead for public disclosure of MSS toxic chemicals for each brand of cigarette sold in the marketplace. United Kingdom authorities have also expressed their intention to follow this mandate.It is difficult to understand the motivation and value of these existing or potentially forthcoming legislative actions. Although there is nearly total agreement among the world's scientists that cigarette smoking is a health hazard, few are bold enough to say with credibility which smoke chemicals or classes of chemicals are responsible for the adverse effects. Therefore, if the specialists are unable to interpret the smoke toxicant data, how is the general public to use their newfound knowledge?The posting of smoke chemical toxicant data is also problematic for the Tobacco Industry for several reasons. First, no standard analytical methods exist for most suspected toxicants. Second, the listing of smoke toxicant yields may ignite a 21st Century version of the ‘tar’ wars in the USA during the 1960s; we have already seen evidence of such competition beginning in the US. Third, and most important of all, no one knows whether or not reducing the yield of one or more publicized MSS toxicant will result in a ‘less hazardous’ cigarette.Assuming that the current situation is approximately as described above, the authors of this paper critically examined the existing lists of MSS toxicants. They discarded chemicals that are no longer relevant, e.g., DDT, N-nitrosodiethanolamine, added known smoke constituents that are glaringly absent, e.g., dioxins, and replaced the existing 1950-60s era nonfiltered cigarette MSS yields with those more representative of the present-day marketplace. Data for the Kentucky reference 1R4F cigarette smoked under standardized smoking conditions, i.e., those established by the International Organization for Standardization (ISO) and the Federal Trade Commission (FTC), are used as a surrogate for the modern-day cigarette whenever possible.A list of smoke toxicants and their approximate concentrations in today's cigarettes is nearly useless without an appropriate ranking of their relative toxicity. Unfortunately, the toxicological data for ranking importance are available for fewer than 5% of the approximately 4800 reported smoke constituents. Although neither of this paper's authors presumes to be a toxicologist, we cite in our discussion several published attempts at ranking smoke toxicants. Specifically, ranking by US Occupational Safety and Health Administration (OSHA) permissible workplace exposure levels, use of US Environmental Protection Agency (EPA) toxicity criteria supplemented with California EPA criteria, and use of the Human Exposure - Rodent Potential methodology and database developed by AMES et al. when data are available. There appears to be a wide divergence in the permissible exposures allowable in the workplace and those advocated by environmental regulators. Thus, it is expected that rankings such as those presented herein will ultimately form the basis of MSS toxic chemical prioritization for either attempts at reduction by product developers or development of standardized analytical methods.This review of MSS toxicants also explores the limitations of toxicological evaluations. The toxicity data used in the above ranking are derived wholly from studies of pure compounds. It is highly improbable that extrapolation of bioassay results determined on an individual compound to that compound when it is a component of a mixture as complex as cigarette MSS is valid. For example, several decades of research involving numerous investigators reported that the benzo[a]pyrene (BaP) content of cigarette smoke condensate (CSC) accounts for only a few percent of the tumor-bearing animals in the skin-painting bioassay. Subsequently they asserted that the tumorigenic polycyclic aromatic hydrocarbons (PAHs) in CSC could account for no more than 3 to 4% of the tumor-bearing animals. Inclusion of promoters, e.g., phenols, raises the level to about 5%. However, several of the same investigators recently claimed that BaP is one of two smoke components responsible for lung cancer in cigarette smokers.While much is written about the hundred or so toxic components in cigarette smoke, little is published about the numerous nontoxic smoke components that have been shown in various bioassays to counteract the effects of the toxic ones. In some cases the inhibiting components are also listed as toxic, e.g., nicotine inhibits the mutagenicity of N-nitrosodimethylamine; the promoter phenol inhibits the tumorigenicity of BaP; the weakly tumorigenic benz[a]anthracene negates the potent tumorigenicity of BaP. On a one-to-one molar basis, many bicyclic, tricyclic, and tetracyclic nontumorigenic PAHs counteract the tumorigenicity of BaP and dibenz[a,h]anthracene.To further illustrate this murky toxicological situation, the history and current knowledge of the importance of tobacco-specific nitrosamines (TSNAs) to the hazards of smoking is reviewed. In brief, these compounds were discovered in tobacco products and found to transfer to MSS (and sidestream smoke). Toxicological evaluations on the pure compounds demonstrated that they are potent carcinogens. Some public health scientists believed that if the levels of TSNAs could be reduced or lowered in MSS, then this would lead to a ‘less hazardous’ cigarette. Once given this assignment, agronomists discovered that at least for flue-cured tobaccos, the levels of TSNAs can be greatly reduced through the use of indirect heating in the curing barns. This was wonderful news. However, toxicologists soon conducted experiments comparing the toxicity of MSS from flue-cured cigarettes containing high and ultra-low concentrations of TSNAs. It must have been a surprise to these investigators when they could find no significant difference between the toxicities of the two smokes.Some public health scientists have asserted that the reduction of the per cigarette ‘tar’ delivery below 15 mg/cig does not reduce the risk from smoking because of the hazard resulting from the higher levels of additives used to maintain consumer acceptability. Although no data in support of this assertion have ever been offered, much data generated during the past decade contradict the assertion. Ingredient addition at the usual level or at levels several times greater than normal does produce some minor changes in the smoke chemistry, but these changes do not result in any adverse biological response as measured in various bioassays to determine mutagenicity, tumorigenicity, etc.From our review of the literature gathered to prepare this paper, we have come to several conclusions. These include the following:1. It is possible to prepare a list of the known toxicants in MSS and to prioritize some of them based upon existing biological data. However, for more than 95% of the known constituents in MSS, there are no biological data.2. Even if there were biological data for most MSS components, extrapolation of this pure-compound knowledge to the biological properties of a mixture containing them is beyond our scientific ability.3. At our current state of scientific knowledge, no one will ever be able to legitimately claim the development of a ‘less hazardous’ cigarette based solely on the reduction of known toxic chemicals in MSS.4. The approach of reducing ‘tar’ yields of cigarettes appears in retrospect to be the most practical means of producing a ‘less hazardous’ cigarette, because when product developers reduce ‘tar', both the known and unknown toxicants are reduced.5. The ranked toxicants in MSS contain both gas-phase and semi-volatile constituents that appear to be important determinants of toxicity. Some of these constituents, e.g., N-nitrosodimethylamine, phenols, are reduced by triacetin-plasticized cellulose acetate filters. These filters also reduce ‘tar'. Additionally, it is well known that charcoal-containing filters have a high efficiency for removing carbonyl compounds from MSS. Development of more consumer-acceptable products that reduce gas-phase toxicants appears to be another route to a ‘less hazardous’ cigarette.

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Section: The Assertion Of the Generation Of Toxicants From Additivessupporting

confidence: 48%

Toxic Chemicals in Cigarette Mainstream Smoke - Hazard and Hoopla

Rodgman¹,

Green²

2003

Beiträge Zur Tabakforschung International/Contributions to Tobacco Research

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“…Smoke chemistry has been extensively investigated in tobacco (6)(7)(8)(9), as has the impact of ingredients on smoke chemistry (10)(11)(12)(13), and the journal Beitrage zur Tabakforshchung has published many papers on smoke chemistry since 1961. However, there are substantially fewer investigations into the chemical characterization of the smoke arising from marijuana cigarettes.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Mainstream and Sidestream Marijuana and Tobacco Cigarette Smoke Produced under Two Machine Smoking Conditions

Moir

Rickert²,

Levasseur³

et al. 2007

Chem. Res. Toxicol.

405

313

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The chemical composition of tobacco smoke has been extensively examined, and the presence of known and suspected carcinogens in such smoke has contributed to the link between tobacco smoking and adverse health effects. The consumption of marijuana through smoking remains a reality and, among youth, seems to be increasing. There have been only limited examinations of marijuana smoke, including for cannabinoid content and for tar generation. There have not been extensive studies of the chemistry of marijuana smoke, especially in direct comparison to tobacco smoke. In this study, a systematic comparison of the smoke composition of both mainstream and sidestream smoke from marijuana and tobacco cigarettes prepared in the same way and consumed under two sets of smoking conditions, was undertaken. This study examined the suite of chemicals routinely analyzed in tobacco smoke. As expected, the results showed qualitative similarities with some quantitative differences. In this study, ammonia was found in mainstream marijuana smoke at levels up to 20-fold greater than that found in tobacco. Hydrogen cyanide, NO, NO x , and some aromatic amines were found in marijuana smoke at concentrations 3-5 times those found in tobacco smoke. Mainstream marijuana smoke contained selected polycyclic aromatic hydrocarbons (PAHs) at concentrations lower than those found in mainstream tobacco smoke, while the reverse was the case for sidestream smoke, with PAHs present at higher concentrations in marijuana smoke. The confirmation of the presence, in both mainstream and sidestream smoke of marijuana cigarettes, of known carcinogens and other chemicals implicated in respiratory diseases is important information for public health and communication of the risk related to exposure to such materials.

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“…For all blends and combinations of additives, no substantive increase in mutagenicity was observed compared to control cigarettes (227). In conclusion, RODGMAN joined the assessment of DOULL et al (223) and PASCHKE et al (224) "that the components of the flavorant formulation ("top dressing") added to tobacco in the manufacture of cigarettes are not hazardous under the conditions of use". In the second paper (21), RODGMAN reviewed certain aspects of the use of casing materials and humectants in cigarettes.…”

Section: Literature Reviewsmentioning

confidence: 99%

“…• PASCHKE, SCHERER and HELLER (224) In 2002, PASCHKE et al (224) released a literature review based on published scientific studies of the effects of tobacco product ingredients and various experimental additives on tobacco smoke composition and biological activity. The format of this paper was that of an uncommented reference paper rather than a critical review.…”

Section: Literature Reviewsmentioning

confidence: 99%

Influence of Additives on Cigarette Related Health Risks

Klus¹,

Scherer²,

Müller

2012

Beiträge Zur Tabakforschung International/Contributions to Tobacco Research

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Tobacco additives play an important role in the manufacturing and for the quality of tobacco products, particularly cigarettes and roll-your-own tobaccos. Attention is increasingly given to the potential effects of additives on consumer behavior and health. This review is intended to compile, collate and - to some degree - evaluate the wealth of pertinent scientific information available from the published literature and other special sources. At first, the reasons are set forth for the use of additives in cigarette manufacturing. In response to the growing controversy over the attractiveness and addictiveness of smoking, the clarification of terms and concepts is followed by a detailed discussion of two kinds of substances with particular relevance: Additives like ammonium compounds that are claimed to increase nicotine availability, and additives that are claimed to increase nicotine addictiveness.The composition and toxicity of mainstream smoke of cigarettes with and without additives are assessed in several respects. The potentials of pyrolysis studies are explored by looking at a number of key studies and some basic considerations regarding in vitro and in vivo toxicity testing are addressed. Five major literature reviews on additives published between 1994 and 2004, and the results of several comprehensive experimental studies covering a large range of additives, released between 2002 and 2012, are dealt with in detail. Single tobacco additives of particular importance (menthol, glycerol, 1,2-propylene glycol, sorbitol, sugars, cocoa, licorice, citric acid, triacetin, and ammonium compounds) are discussed in dedicated chapters, which are generally subdivided into special sections: Use and toxicological assessment; inclusion level in cigarettes, transfer and pyrolysis; attractiveness and addictiveness; effect on cigarette mainstream smoke composition; effect on cigarette mainstream smoke toxicity. Epidemiological findings and data obtained by the biomonitoring of smokers consuming cigarettes with and without additives are compiled and interpreted specifically for American blend cigarettes, Virginia cigarettes, “French” (dark) cigarettes and menthol cigarettes whereby the focus is on the effects of additives on smoking topography and potential health risks.Opinionated reviews were published in recent years that are compromised by arbitrary selection of sources and unbalanced views. Leaving those unconsidered, the aggregated scientific knowledge shows that tobacco additives have only occasional and limited effects on cigarette mainstream smoke composition, which are almost never reflected in the results of toxicological in vitro assays or in vivo studies. This supports the conclusion that tobacco additives are not likely to increase the known health risks of smoking. There is also no evidence for sustaining claims that certain additives increase nicotine availability or nicotine addictiveness.

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Effects of Ingredients on Cigarette Smoke Composition and Biological Activity: A Literature Overview

Cited by 41 publications

References 70 publications

Toxic Chemicals in Cigarette Mainstream Smoke - Hazard and Hoopla

Toxic Chemicals in Cigarette Mainstream Smoke - Hazard and Hoopla

A Comparison of Mainstream and Sidestream Marijuana and Tobacco Cigarette Smoke Produced under Two Machine Smoking Conditions

Influence of Additives on Cigarette Related Health Risks

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