**4. Conclusions**

In summary, based on NMR-guided isolation, two new (**1** and **2**) and one known (**3**) compounds were isolated from the culture broth of the deep-sea fungus *Aspergillus unguis* IV17-109. The planar structures of the new compounds were elucidated by a comprehensive analysis and comparison of their spectroscopic data with the values in the literature (HRESIMS, 1D, and 2D NMR). Compound **2** is a rare natural product with an unusual cysteinol moiety. The absolute configuration of **2** was determined by comparing its optical rotation sign with that of the synthesized analogs (**4** and **5**). Compounds **1** and **2** were preliminarily screened for their in vitro anti-inflammatory activity. Compound **1** showed moderate activity with an IC50 value of 20.0 μM. To the best of our knowledge, this is the first report on linear nitrogenous secondary metabolites isolated from *Aspergillus unguis*. This research expanded the biological and chemical diversities of fungal natural products.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/md20030217/s1, Figures S1–S15, HRESIMS data, 1H, 13C, 1H-1H COSY, HSQC, HMBC, NOESY NMR experimental spectra of compounds **1** and **2**. Figures S16–S24, ESIMS, 1H NMR, 13C NMR experimental spectra of **4**–**7**.

**Author Contributions:** Conceptualization, H.J.S.; investigation, C.V.A. and Y.D.Y.; resources, H.- S.L. and C.-S.H.; writing—original draft preparation, C.V.A.; writing—review and editing, H.J.S.; visualization, J.S.K.; project administration, H.J.S.; funding acquisition, H.J.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was supported in part by the Korea Institute of Ocean Science and Technology (Grant PE99952) and the Ministry of Oceans and Fisheries, Republic of Korea (Grants PM62500 and no. 20170411).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in the article are available in the Supplementary Materials.

**Acknowledgments:** The authors express gratitude to Jung Hoon Choi, Korea Basic Science Institute, Ochang, Korea, for providing mass data.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

