Kejian Liu

Evaluation of whole cigarette smoke induced oxidative stress in A549 and BEAS-2B cells.

Cigarette smoke is a complex and oxidative aerosol. Previous researches on the hazards of cigarette smoke mainly focused on the adverse bioeffects induced by its condensates or gas vapor phase, which ignored the dynamic processes of smoking and the cigarette smoke aging. To overcome these disadvantages, we performed air-liquid interface exposure of whole smoke, which used native and unmodified smoke and ensured the exposure similar to physiological inhalation. Our results indicated that whole cigarette smoke induced lung epithelial cells (A549) and bronchial epithelial cells (BEAS-2B) damages in cytotoxicity assays (methyl thiazoly tetrazolium and neutral red uptake assays). In addition, A549 and BEAS-2B cells showed oxidative damages in whole smoke exposure, with concentration change of several biomarkers (reduced and oxidized glutathione, malondialdehyde, 4-hydroxyhydroxy-2-nonenal, extracellular superoxide dismutase, and 8-hydroxyl deoxyguanosine). These results indicate that whole smoke-induced oxidative stress occurs in two different kinds of cells at air-liquid interface.

Separation and detection of polar cuticular components from Oriental tobacco leaf by integration of normal-phase liquid chromatography fractionation with reversed-phase liquid chromatography-mass spectrometry

Integration of normal-phase LC (NPLC) fractionation with RPLC-ESI/MS was established to detect the polar fractions of cuticular components from Oriental tobacco leaf. NPLC was selected for the fractionation of polar components of cuticular leaf extract, after being concentrated with rotary evaporator, each of the enriched fractions was further analyzed by RPLC-ESI/MS. In total, 83 compounds were finally detected including 45 cembranoids, 15 labdanoids, 20 sucrose esters, and 3 glucose esters (or fructose esters). Three cembranoids and seven labdanoids possibly are new diterpenoids. Glucose esters (or fructose esters) are also reported in Nicotiana tobacco for the first time.

Distribution of toxic chemicals in particles of various sizes from mainstream cigarette smoke

Abstract To accurately estimate the risk of inhaling cigarette smoke containing toxic chemicals, it is important that the distribution of these chemicals is accurately measured in cigarette smoke aerosol particles of various sizes. In this study, a single-channel smoking machine was directly coupled to an electrical low-pressure impactor. The particles of mainstream cigarette smoke were collected using 12 polyester films, and the particulate matter (PM) was characterized. Nicotine, tobacco-specific N-nitrosamines (TSNAs, including NNN, NAT, NAB, and NNK), polycyclic aromatic hydrocarbons (PAHs, including benzo(a)pyrene (BaP), benzo(a)anthracene, and chrysene), and heavy metals (including Cr, As, Cd, and Pb) present in the particles of different sizes were analyzed by GC, HPLC-MS/MS, GC/MS, or ICP-MS, respectively. The results demonstrated that the nicotine, TSNAs, PAHs, and heavy metals in mainstream cigarette smoke were dispersed over a particle size ranging from 0.1 μm to 2.0 μm, and the concentration of these toxic chemicals initially increased and then decreased the particle size grew. The distribution of nicotine was uniform for the PM in the size ranges of less than 0.1 μm, 0.1–1.0 μm, and 1.0–2.0 μm, TSNAs and heavy metals in particles of less 0.1 μm were more abundant, and PAHs in fine particles were also more abundant.