Characterization of Spirobisnaphthalenes from an Endophytic Fungus <i>Edenia</i> sp. Associated with <i>Drymaria cordata</i> and Insights into Their Biological Activity

Fungal secondary metabolites have been increasingly sought after as an alternative strategy to herbicides and a source of new medicines. Twenty spirobisnaphthalenes (SBNs) were isolated from the fermentation broth of <i>Edenia</i> sp. YUD20003 from the herb <i>Drymaria cordata</i> (L.) Willd. in China, including eight new SBNs (<b>1</b>-<b>8</b>) and a new phenolic dinaphthoether (<b>9</b>). Their chemical structures and absolute configurations were elucidated on the basis of comprehensive spectroscopic analyses. The biosynthetic pathway of these SBNs was proposed. The insight into biological activity showed that these SBNs not only demonstrated significant cytotoxicity against five human cancer cell lines but also exhibited potent antimicrobial activities against both <i>Candida albicans</i> and <i>Staphylococcus aureus</i>. Notably, <b>3</b>, <b>5</b>-<b>7</b>, and <b>9</b> demonstrated an inhibitory effect on acetylcholinesterase that was on par with tacrine. Additionally, compound <b>7</b> effectively inhibited the germination of the weed <i>Setaria viridis</i>, suggesting its potential as a biological herbicide. The research highlights the potential of these SBNs as bioactive natural products with agrochemical and pharmaceutical applications.