Molecular Networking-Driven Discovery of Antifungal Azaphilone Dimers from the Marine-Derived Fungus Humicola sp. HK1-8

A novel azaphilone dimer, humilone A (1), along with its related monomer, humilone B (2), was isolated from cultures of the marine-derived fungus Humicola sp. HK1-8 using a molecular networking-guided discovery approach. Further investigation of the molecular family of azaphilone dimers led to the putative identification of four analogues, humilones C-F (3-6), based on systematic analysis of their characteristic MS/MS fragmentation patterns. Detailed fragmentation studies of the dimers revealed that the predominant cleavage fragments originated from C-C bond scission at the dimeric methylene bridge. Compound 1 displayed antifungal activity against Rhizoctonia solani.