Apoptotic Activity of New Oxisterigmatocystin Derivatives from the Marine-Derived Fungus Aspergillus nomius NC06

Sponge-derived fungi have recently attracted attention as an important source of interesting bioactive compounds. NC06 was isolated from the marine sponge . This fungus was cultured on rice medium and yielded four compounds including three new oxisterigmatocystins, namely, J, K, and L ( , , and ), and one known compound, aspergillicin A ( ). Structures of the compounds were elucidated by 1D and 2D NMR spectroscopy and by high-resolution mass spectrometry. The isolated compounds were tested for cytotoxic activity against HT 29 colon cancer cells, where compounds , , and exhibited IC values of 6.28, 15.14, and 1.63 µM, respectively. Under the fluorescence microscope by using a double staining method, HT 29 cells were observed to be viable, apoptotic, and necrotic after treatment with the cytotoxic compounds , , and . The result shows that compounds and were able to induce apoptosis and cell death in HT 29 cells.