Department of Food Science, Pennsylvania State University, College of Agricultural Sciences, University Park, PA, USA.
Department of Public Health Sciences, Pennsylvania State University Tobacco Center of Regulatory Science (TCORS), Pennsylvania State University College of Medicine, 500 University Dr., Mail Code: CH69, Hershey, PA 17033, USA.
Free Radic Biol Med. 2018 May 20;120:72-79. doi: 10.1016/j.freeradbiomed.2018.03.020. Epub 2018 Mar 13.
Flavoring chemicals, or flavorants, have been used in electronic cigarettes (e-cigarettes) since their inception; however, little is known about their toxicological effects. Free radicals present in e-cigarette aerosols have been shown to induce oxidative stress resulting in damage to proliferation, survival, and inflammation pathways in the cell. Aerosols generated from e-liquid solvents alone contain high levels of free radicals but few studies have looked at how these toxins are modulated by flavorants.
We investigated the effects of different flavorants on free radical production in e-cigarette aerosols.
Free radicals generated from 49 commercially available e-liquid flavors were captured and analyzed using electron paramagnetic resonance (EPR). The flavorant composition of each e-liquid was analyzed by gas chromatography mass spectroscopy (GCMS). Radical production was correlated with flavorant abundance. Ten compounds were identified and analyzed for their impact on free radical generation.
Nearly half of the flavors modulated free radical generation. Flavorants with strong correlations included β-damascone, δ-tetradecalactone, γ-decalactone, citral, dipentene, ethyl maltol, ethyl vanillin, ethyl vanillin PG acetal, linalool, and piperonal. Dipentene, ethyl maltol, citral, linalool, and piperonal promoted radical formation in a concentration-dependent manner. Ethyl vanillin inhibited the radical formation in a concentration dependent manner. Free radical production was closely linked with the capacity to oxidize biologically-relevant lipids.
Our results suggest that flavoring agents play an important role in either enhancing or inhibiting the production of free radicals in flavored e-cigarette aerosols. This information is important for developing regulatory strategies aimed at reducing potential harm from e-cigarettes.
自电子烟问世以来，调味化学品（或调味剂）就一直被用于电子烟中；然而，人们对其毒理学效应知之甚少。电子烟气溶胶中存在的自由基已被证明会引起氧化应激，从而导致细胞增殖、存活和炎症途径受损。仅从电子烟液溶剂中产生的气溶胶就含有高水平的自由基，但很少有研究探讨这些毒素如何被调味剂调节。
我们研究了不同调味剂对电子烟气溶胶中自由基生成的影响。
使用电子顺磁共振（EPR）捕获并分析了 49 种市售电子烟液口味产生的自由基。通过气相色谱质谱联用仪（GCMS）分析了每种电子烟液的调味剂成分。自由基的产生与调味剂的丰度相关。鉴定了 10 种化合物，并分析了它们对自由基生成的影响。
近一半的口味调节了自由基的生成。具有强相关性的调味剂包括β-大马酮、δ-十四内酯、γ-癸内酯、柠檬醛、双戊烯、乙基麦芽酚、乙基香兰素、乙基香兰素 PG 缩醛、芳樟醇和胡椒醛。双戊烯、乙基麦芽酚、柠檬醛、芳樟醇和胡椒醛以浓度依赖的方式促进自由基的形成。乙基香兰素以浓度依赖的方式抑制自由基的形成。自由基的产生与氧化生物相关脂质的能力密切相关。
我们的研究结果表明，调味剂在增强或抑制调味电子烟气溶胶中自由基的产生方面起着重要作用。这些信息对于制定旨在减少电子烟潜在危害的监管策略非常重要。
