Moghbel Nahid, Ryu BoMi, Cabot Peter J, Ratsch Angela, Steadman Kathryn J
School of Pharmacy, The University of Queensland, Brisbane, Qld 4072, Australia.
School of Pharmacy, The University of Queensland, Brisbane, Qld 4072, Australia.
Toxicol Lett. 2016 Jul 8;254:45-51. doi: 10.1016/j.toxlet.2016.05.011. Epub 2016 May 10.
The Aboriginal population of Central Australia use endemic Nicotiana species to make a smokeless tobacco product known usually as pituri or mingkulpa. Nicotiana leaves are masticated with wood ash into a 'quid' that is chewed/sucked for absorption of nicotine. In addition to nicotine, smokeless tobacco products contain a spectrum of biologically active compounds that may contribute to effects on health. The objective of this study was to quantify nicotine, and related alkaloids and tobacco specific nitrosamines (TSNAs), in Nicotiana leaves used in pituri, and compare in vitro toxicity of pure nicotine with Nicotiana leaf extract at the same concentration of nicotine. An aqueous extract of dry leaves of Nicotiana gossei and a reference smokeless tobacco (CORESTA CRP2) were quantified for major pyridine alkaloids and TSNAs using HPLC-UV and LC-MS/MS. A range of extract concentrations and corresponding concentrations of nicotine standard were tested using an MTS assay to measure human lung epithelium cell (A549) survival. Cells treated for 24h with the maximum concentration of 1.5mg/ml of nicotine resulted in 77% viability. In contrast, extracts from N. gossei leaves and CRP2 containing a similar concentration of nicotine (1.3mg/ml) resulted in remarkably lower viability of 1.5 and 6%, respectively. Comparison of cytotoxicity of pure nicotine with that of the extracts revealed that nicotine was not the source of their cytotoxicity. Other biologically active compounds such as the known carcinogens NNK and NNN, derived from nicotine and nornicotine and found to be present in the smokeless tobacco extracts, may be responsible.
澳大利亚中部的原住民使用当地特有的烟草属植物制作一种通常称为皮特鲁里或明库尔帕的无烟烟草产品。烟草属植物的叶子与木灰一起咀嚼成“咀嚼物”，通过咀嚼/吮吸来吸收尼古丁。除尼古丁外，无烟烟草产品还含有一系列生物活性化合物，可能对健康产生影响。本研究的目的是对皮特鲁里中使用的烟草属植物叶子中的尼古丁、相关生物碱和烟草特有亚硝胺（TSNAs）进行定量，并比较相同尼古丁浓度下纯尼古丁与烟草属植物叶提取物的体外毒性。使用高效液相色谱-紫外检测法（HPLC-UV）和液相色谱-串联质谱法（LC-MS/MS）对戈氏烟草干叶的水提取物和参考无烟烟草（CORESTA CRP2）中的主要吡啶生物碱和TSNAs进行定量。使用MTS法测试一系列提取物浓度和相应的尼古丁标准浓度，以测量人肺上皮细胞（A549）的存活率。用最高浓度1.5mg/ml的尼古丁处理细胞24小时后，细胞存活率为77%。相比之下，戈氏烟草叶提取物和CRP2中尼古丁浓度相似（1.3mg/ml），但细胞存活率分别显著降低至1.5%和6%。纯尼古丁与提取物的细胞毒性比较表明，尼古丁不是其细胞毒性的来源。其他生物活性化合物，如已知的致癌物NNK和NNN，它们由尼古丁和去甲烟碱衍生而来，且存在于无烟烟草提取物中，可能是造成这种情况的原因。
