An Artemisia-derived natural product-based fluorescent probe for the bitter taste receptor hTAS2R38

The discovery of taste receptors hTAS2Rs expression in extra oral tissue, especially in the gastrointestinal tract and in the respiratory system, has endowed bitter receptors of functionalities that exceed the simple perception of taste and flavour. In particular, stimulation of hTAS2Rs by bitter agents in the airway smooth muscle triggers bronchodilation of possible pharmacological relevance. To study the receptor localization in pulmonary smooth muscle cells and to investigate their biological response to hTAS2R38 activation, we have developed a fluorescent probe for hTAS2R38 starting from the sesquiterpene lactone costunolide, available in multigram amounts from Artemisia umbelliformis Lam. The N-methylanthranilate-containing probe demonstrated a very low cytotoxicity compared to the natural product toward human airway smooth muscle cells and epithelial bronchial cells, but fully retained its binding to hTAS2R38, making it possible the fluorescent detection of cells expressing this bitter receptor.