Pyridone alkaloids from the scale-insect pathogenic fungus Hypocrella discoidea BCC 71382

Abstract Hypocrellutins A–C ( 1 – 3 ), 2- and 4-pyridone alkaloids, were isolated from cultures of the scale-insect pathogenic fungus Hypocrella discoidea BCC 71382. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. The absolute configuration of hypocrellutin B ( 2 ) was determined by ECD calculation. Their plausibly biosynthetic pathways are proposed. All isolated compounds were inactive in the antifungal, antimalarial, antitubercular, and cytotoxic activity assays.