Scientists Discover One of the Bitterest Substances: Oligoporin D

German researchers have identified oligoporin D, a compound extracted from the fungus *Amaropostia stiptica*, as one of the most intensely bitter substances known. Discovered by scientists at the Leibniz Institute for Food Systems Biology at the Technical University of Munich and the Leibniz Institute of Plant Biochemistry in Halle (Saale), the finding, published in the *Journal of Agricultural and Food Chemistry*, expands understanding of bitter compounds and their receptors. A mere gram of oligoporin D is perceptible even when diluted in the volume of 106 bathtubs of water. The research team, led by Maik Behrens and Norbert Arnold, isolated three previously unknown compounds from the non-toxic but extremely bitter fungus. Through cell-based assays, they demonstrated that these compounds activate at least one of the 25 human bitter taste receptor types. Oligoporin D notably stimulates the TAS2R46 bitter taste receptor at extremely low concentrations (approximately 63 millionths of a gram per liter). Researchers believe bitter taste receptors evolved to warn against harmful substances, though not all bitter compounds are toxic, and not all toxins taste bitter. These receptors are found not only in the mouth but also in organs like the stomach, intestines, heart, and lungs, suggesting a broader physiological role beyond taste perception. "Our results contribute to expanding our knowledge about the molecular diversity and mode of action of natural bitter compounds," says Behrens. This knowledge could lead to novel applications in food and health research, such as developing palatable foods that positively influence digestion and satiety.