It is well recognized that chemical composition of tobacco is highly associated with the flavor of tobacco products and the risk of smoking. In view of the fact that the unique combination of tobacco maturation stages and cultivation conditions result in unique secondary metabolites, comprehensive studies on the chemical constituents of tobacco sample of different origins harvested at different maturation stages might provide valuable information to identify superior cultivation condition and the appropriate time to harvest tobacco.
Prof. ZHOU Ｙan’s group of Chengdu Institute of Biology CAS collaborated with researchers of Kunming Institute of Botany CAS developed a gas chromatography−mass spectrometry (GC−MS) and high performance liquid chromatography−photodiode array-quadrupole time-of-flight mass spectrometry (HPLC-PDA-QTOF-MS) to analyze the fat-soluble and polar components in 12 batches of tobacco samples of three origins and four maturities.
The GC−MS analyses showed that tobacco samples harvested at 40 days after transplantation exhibited more fat-soluble components, while those harvested at 100 days after transplantation exhibited the least fat-soluble components. Tentatively, identification of the main components as well as quantitative analyses of eight reference compounds, including five alkaloids, two polyphenols, and a coumarin, was performed by the developed HPLC−QTOF-PDA method. Results showed significant differences among origins and maturities in the contents of these compounds.
The nicotine contents showed great variety among the 12 tobacco samples. The highest nicotine content were found in a sample from Zhengzhou harvested at 40 days after transplantation (ZZ-T with 25399.39 ± 308.95 μg/g), and the lowest nicotine level was detected in a sample from Zunyi harvested at 60 days after transplantation (ZY-X with 1654.49 ± 34.52 μg/g). The highest level of rutin was found in a Jiangchuan sample harvested at 60 days after transplantation (JC-X with 725.93 ± 40.70 μg/g), and the lowest rutin content was detected in a Zunyi tobacco sample harvested at 60 days after transplantation (ZY-X with 87.42 ± 2.78 μg/g).
The developed method provided a convenient approach which might be applied for rapid maturity evaluation and tobacco flavor identification and also holds the potential for analysis of compounds present in other plants.This work has been published in Journal of Agricultural and Food Chemistry.