Aegyoxepane: A New Oxepane Derivative from the Fungus Aspergillus aegyptiacus

Abstract

Background: The fungi have been a wealthy source of secondary metabolites with novel structures and diverse pharmacological activities. Aspergillus a large diversified genus, is one of the main contributors to bioactive metabolites originated from fungal source. Former phytochemical study of A. aegyptiacus isolated cotton textile resulted in the isolation and characterization of pyrrolidine alkaloids and ophiobolin sesterterpenoids. Method: The fungus was cultivated and the broth and mycelium were segregated by filtration. The concentrated EtOAc extract of the fungal broth was submitted to Sephadex LH-20, SiO2, and HPLC CC to get four compounds. UV, IR, NMR, and MS spectral analyses as well as molecular modelling were utilized for structure elucidation of these compounds. Cytotoxic activity of 1-4 was evaluated towards MCF7, A549, HeLa, HCT116, and PC12 cancer cell lines using MTT assay. Results: A new oxepane derivative namely, aegyoxepane (3), along with (22E,24R)-stigmasta-5,7,22- trien-3-β-ol (1), variculanol (2), and 1-methylimidazolidin-2-one (4) were separated from the EtOAc extract of A. aegyptiacus. Compounds 2 and 4 exhibited significant cytotoxic activities towards HeLa and HCT116 cell lines with IC50 values 3.97 and 4.51 μM and 2.89 and 2.91 μM, respectively compared to adriamycin. Conclusion: Aspergillus aegyptiacus has been proven to be a rich source of diverse classes of chemical constituents. The chromatographic treatment of the EtOAc of A. aegyptiacus produced four compounds, one of them was new (3) and other (4) was isolated for the first time from natural origin. They exhibited strong to moderate cytotoxic potential towards MCF7, HCT116, and HeLa cell lines. Keywords: Aegyoxepane, Aspergillus aegyptiacus, oxepane, cytotoxicity.