Comparative GC-MS and phytochemical profiling of green and cured leaves of Nicotiana tabacum (PT76) consumed as Khaini in Jharkhand

Nicotiana tabacum (PT76 variety) is a major source of bioactive compounds, yet its chemical composition undergoes substantial transformation during post-harvest curing. This study aimed to compare the phytochemical profiles of green (GL) and cured tobacco leaves (CL) consumed locally as khaini in Bihar and Jharkhand, using both qualitative phytochemical screening and Gas Chromatography–Mass Spectrometry (GC–MS). Aqueous extracts of green and cured leaves were subjected to standard phytochemical tests, revealing the presence of alkaloids, flavonoids, glycosides, phenolic compounds, proteins, carbohydrates, anthocyanidins, phlobatannins, terpenoids, saponins, and steroids. Methanolic extracts of both samples were analyzed, and compounds were identified based on retention times and spectral matching with the NIST and Wiley library. The cured leaf extract exhibited 42 compounds, with (S)-3-(1-methylpyrrolidin-2-yl)pyridine (nicotine 88.83%) as the dominant constituent, along with potentially harmful compounds such as 1,2,3,6-tetrahydro-2,3′-bipyridine (1.19%), 4-nitroso-3-(pyrrolidin-1-yl)phenol (0.38%), and 1-methyl-5-(pyridin-3-yl)pyrrolidin-2-one (0.80%). In contrast, the green leaf extract contained 25 compounds including nicotine, naphthalene, 1,2,3,6-tetrahydro-2,3′-bipyridine, neophytadiene, phytol, stigmasterol, β-sitosterol, hexadecanoic acid methyl ester, methyl stearate, and 9,12-octadecadienoic acid methyl ester. Additional compounds include sclareolide, palmitic acid derivatives, and various long-chain hydrocarbons and esters. These findings indicate that curing significantly alters the chemical landscape of N. tabacum leaves, increasing the presence of toxicants and nitrosamine precursors. The study provides chemical evidence supporting the toxicological concerns associated with cured tobacco products and highlights the need for public health awareness regarding the risks of smokeless tobacco consumption.