Antimicrobial aromatic Butenolides and anthraquinone derivative produced in cocultures of Cordyceps militaris ZYb8 and Malbranchea ostraviensis SS1.

Integrated with LC-MS/MS-based molecular networking analysis, eight previously undescribed compounds-eutypoid G-K (1-5), gotjawalides A-B (6-7), and ocauxarthrol B (8)-along with 11 known natural products (9-19) were isolated from the coculture of Cordyceps militaris ZYb8 and Malbranchea ostraviensis SS1. The structures of those previously undescribed compounds (1-8) were elucidated through comprehensive spectroscopic data analyses, including NMR, HRESIMS, UV, and IR. The absolute configurations of compounds 6-8 were assigned by comparing experimental electronic circular dichroism (ECD) spectra with theoretically calculated spectra. Antimicrobial assays revealed that compounds 1-13, 15-16, and 19 exhibited weak to moderate selective antibacterial activities against S. aureus, B. subtilis, S. pneumoniae, and K. pneumoniae with MIC values ranging from 4 to 128 μg/mL.