Unraveling molecular mechanisms of cigarette smoke bitterness via chemical profiling and bitter taste receptor activation analysis

Tobacco metabolites play a crucial role in shaping the sensory experience of tobacco products, such as cigarettes. Bitter metabolites in tobacco not only serve as protective agents in plants, but also significantly influence the overall flavor profile of cigarettes. In this study, we employed an integrated approach combining chemical profiling, cell-based calcium imaging assays, and molecular docking studies to identify key bitter compounds in cigarette smoke and explore the molecular mechanisms underlying their bitterness. We analyzed 22 commercial cigarette brands, revealing notable variability in bitterness perception. GC-MS analysis identified 88 compounds in mainstream cigarette smoke (MCS), with pyridines, esters, and phenols being the most prevalent. Using a TAS2R14-Gα16gust44-HEK293T cell-based assay, we objectively measured bitterness and identified nicotine, succinimide, and scopoletin as key bitter compounds through correlation analysis. Molecular docking studies provided detailed insights into the interactions of these compounds with the TAS2R14 receptor, highlighting significant hydrogen bonding and hydrophobic interactions. This integrated methodology not only identifies key contributors to cigarette bitterness but also enhances our understanding of the molecular basis of bitterness perception in tobacco. These findings pave the way for future studies to further elucidate the complex interactions of bitter compounds. This understanding of the links between tobacco bitterness and consumption holds significant implications for public health and tobacco control initiatives.