GNPS-guided discovery of eremophilane sesquiterpenoids from Penicillium roqueforti and their phytotoxic activities.

Abstract

The GNPS (Global Natural Products Social Molecular Networking) strategy enable the targeted isolation of eremophilane sesquiterpenoids from Penicillium roqueforti, a fungus isolated from the rhizosphere soil of Hypericum beanii N. Robson collected in the Shennongjia Forestry District, Hubei Province, China. The isolated metabolites comprised eleven previously undescribed lactam- or pyrrole-bearing eremophilane sesquiterpenoid derivatives (1-11), six undescribed highly oxidized analogues (12 and 14-18), and three known congeners (13 and 19-20). Their structures, including absolute configurations, were elucidated through comprehensive spectroscopic analyses, DP4+ probability analysis, ECD calculations, and single-crystal X-ray diffraction. The agrochemical potential of selected compounds (1-13) was evaluated using phytotoxic and antifungal assays. Compound 7 displayed moderate, dose-dependent inhibition of Medicago sativa seed germination, whereas the remaining tested compounds were inactive under the same conditions. By contrast, none of the tested compounds exhibited significant antifungal activity against a panel of nine fungal pathogens at 50 μM. Overall, this work broadens the structural diversity of fungal eremophilane sesquiterpenoids and highlights compound 7 as a moderate phytotoxin.