*Article* **Nitrogen-Containing Secondary Metabolites from a Deep-Sea Fungus** *Aspergillus unguis* **and Their Anti-Inflammatory Activity**

**Cao Van Anh 1,2, Yeo Dae Yoon 3, Jong Soon Kang 3, Hwa-Sun Lee 1, Chang-Su Heo 1,2 and Hee Jae Shin 1,2,\***


**Abstract:** *Aspergillus* is well-known as the second-largest contributor of fungal natural products. Based on NMR guided isolation, three nitrogen-containing secondary metabolites, including two new compounds, variotin B (**1**) and coniosulfide E (**2**), together with a known compound, unguisin A (**3**), were isolated from the ethyl acetate (EtOAc) extract of the deep-sea fungus *Aspergillus unguis* IV17-109. The planar structures of **1** and **2** were elucidated by an extensive analysis of their spectroscopic data (HRESIMS, 1D and 2D NMR). The absolute configuration of **2** was determined by comparison of its optical rotation value with those of the synthesized analogs. Compound **2** is a rare, naturally occurring substance with an unusual cysteinol moiety. Furthermore, **1** showed moderate anti-inflammatory activity with an IC50 value of 20.0 μM. These results revealed that *Aspergillus unguis* could produce structurally diverse nitrogenous secondary metabolites, which can be used for further studies to find anti-inflammatory leads.

**Keywords:** deep-sea fungus; *A. unguis*; variotin; coniosulfide; anti-inflammatory
