Overexpression of global regulator AalaeA leads to the discovery of a new diterpene in fungus Aspergillus assiutensis HDN21-0609.

A new fusicoccane-derived diterpenoid (1) was isolated from the engineered overexpression strain of Aspergillus assiutensis HDN21-0609, along with seven known compounds (2-8). Their chemical structures, including configurations, were elucidated by detailed analysis of extensive NMR spectra, HRESIMS, ECD calculations, and single-crystal X-ray diffraction analysis. Compounds 2, 3, and 4 exhibited varying degrees of antibacterial activity. Compounds 4, 5, and 8 showed potent antioxidant activity, with IC50 values of 10.33 μM, 12.94 μM, and 9.44 μM, respectively.