Harzianopyridone is a natural inhibitor of mitochondrial complex II (succinate:ubiquinone oxidoreductase). It also inhibits the NADH-fumarate reductase activity of fungal mitochondria and the quinol-fumarate reductase activity of anaerobic parasite mitochondria. Harzianopyridone has potent antibiotic activities and its synthesis by the fungus Trichoderma is stimulated by co-culture with viable or nonviable pathogens.
![(-)-4-Hydroxy-5,6-dimethoxy-3-[(E)-2-methyl-1-oxo-4-hexenyl]pyridine-2(1H)-one](https://www.chemicalbook.com/CAS/GIF/137813-88-8.gif)