Ten Ring-B Aromatized Ergosterols from Aspergillus spectabilis

Spectasterols F−O ( 1 − 10 ), ten interesting ergosterols with an aromatized B ring, were obtained from Aspergillus spectabilis. Their structures and absolute configurations were determined based on HRESIMS, NMR, single-crystal X-ray diffraction analyses, and electronic circular dichroism (ECD) calculations. Structurally, these aromatic ergosterols feature versatile side chains, and compound 4 is an unusual C23 ergosterol with a shorter side chain due to the oxidation cleavage between C-23 and C-24. All compounds were evaluated for their neuroprotective activities, and compound 8 could reduce apoptosis and protect the mitochondria function in glutamate-induced SH-SY5Y cells dose-dependently.