Moghbel Nahid, Ryu BoMi, Ratsch Angela, Steadman Kathryn J
School of Pharmacy, The University of Queensland, Brisbane, Qld, 4072, Australia.
School of Nursing, Midwifery and Social Work, The University of Queensland, Brisbane, Qld, 4072, Australia.
Heliyon. 2017 Dec 1;3(11):e00469. doi: 10.1016/j.heliyon.2017.e00469. eCollection 2017 Nov.
A range of endemic species are chewed as a smokeless tobacco by several Aboriginal populations of Australia. In tobacco research, nicotine to nornicotine conversion is important because nornicotine lowers tobacco quality and is detrimental to health. A diverse group of cytochrome P450 genes with different transcriptional regulations are involved in this conversion. The primary aims of this study were to quantify the pyridine alkaloids and investigate nicotine to nornicotine conversion in laboratory-grown Australian spp. Nicotine, nornicotine, anatabine, anabasine, myosmine and cotinine were quantified in fresh leaves of 24 out of the 26 recognised Australian taxa. Conserved regions of CYP82E related genes were PCR amplified in all studied taxa. The conversion process in fresh leaves was compared with that in leaves that underwent a simulated curing process for species that we identified as being high converters (, ) and low converters (). Agarose gel electrophoretic analysis of CYP82E related genes obtained from the PCR amplification of the cDNA in fresh versus leaves with simulated curing showed about a 3-fold increase in transcript accumulation levels in cured leaves of the high converter species, while the transcript accumulation in and maintained a steady basal level and increased by a small amount in . This suggests the presence of functional loci that are triggered by curing in only high converter species and indicates a potential risk for chewers of high converter species.
澳大利亚的几个原住民群体将一系列本地物种当作无烟烟草咀嚼。在烟草研究中，尼古丁向去甲烟碱的转化很重要，因为去甲烟碱会降低烟草质量且对健康有害。一组具有不同转录调控的细胞色素P450基因参与了这种转化。本研究的主要目的是对吡啶生物碱进行定量，并研究实验室培育的澳大利亚烟草属物种中尼古丁向去甲烟碱的转化。在26个已确认的澳大利亚烟草属分类群中的24个的新鲜叶片中对尼古丁、去甲烟碱、假木贼碱、新烟草碱、麦斯明和可替宁进行了定量。在所有研究的分类群中对CYP82E相关基因的保守区域进行了PCR扩增。对于我们确定为高转化物种（、）和低转化物种（）的，将新鲜叶片中的转化过程与经过模拟调制过程的叶片中的转化过程进行了比较。对新鲜叶片与模拟调制叶片的cDNA进行PCR扩增得到的CYP82E相关基因的琼脂糖凝胶电泳分析表明，高转化物种调制叶片中的转录本积累水平增加了约3倍，而和的转录本积累保持稳定的基础水平，在中略有增加。这表明仅在高转化物种中存在由调制触发的功能位点，并表明高转化物种的咀嚼者存在潜在风险。
