Eight naphtho-gamma-pyrones (NγPs) (1-8), together with four known biosynthetically related coumarin derivatives (9-12), were isolated from the potato dextrose agar media of a marine-derived fungus Aspergillus niger S-48. Among them, natural compounds 1 and 2 were tentatively subjected to benzohydrazide reaction to evaluate the importance of pyran rings in NγPs. Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and MS spectra. Compounds 1-4 showed obvious activity for reducing cholesterol absorption verging on ezetimibe. This work highlighted the potential of natural NγPs as NPC1L1 inhibitors.
Keywords: Aspergillus niger; Niemann-Pick C1-Like 1; cholesterol; naphtho-gamma-pyrones (NγPs); natural products.