N-Hydroxypyridone alkaloids, chromone derivatives, and tetrahydroxanthones from the scale-insect pathogenic fungus Orbiocrella sp. BCC 33248

摘要

Six new compounds, an N-hydroxypyridone glucoside, orbiocrellin A (1), its aglycone orbiocrellin B (2), chromone glucosides 3 and 4, a dihydrochromone 5a/5b, and a chromone 6, were isolated from the scale-insect pathogenic fungus Orbiocrella sp. BCC 33248. Orbiocrellin A (1) exhibited antimalarial activity against Plasmodium falciparum K1 (IC_(50) 3.1 mg/mL) while it was non-cytotoxic. In contrast, orbiocrellin B (2) showed both antimalarial (IC_(50) 2.1 mg/mL) and cytotoxic (NCI-H187 cells, IC_(50) 0.70 μg/mL) activities.