*Article* **New Antibacterial Secondary Metabolites from a Marine-Derived** *Talaromyces* **sp. Strain BTBU20213036**

**Fuhang Song <sup>1</sup> , Yifei Dong <sup>1</sup> , Shangzhu Wei <sup>2</sup> , Xinwan Zhang <sup>2</sup> , Kai Zhang <sup>1</sup> and Xiuli Xu 2,\***

	- <sup>2</sup> School of Ocean Sciences, China University of Geosciences, Beijing 100083, China; 2111180016@cugb.edu.cn (S.W.); zhangxinwan@cugb.edu.cn (X.Z.)
	- **\*** Correspondence: xuxl@cugb.edu.cn

**Abstract:** New polyketide-derived oligophenalenone dimers, bacillisporins K and L (**1** and **2**) and xanthoradone dimer rugulosin D (**3**), together with four known compounds, bacillisporin B (**4**), macrosporusone D (**5**), rugulosin A and penicillide (**6** and **7**), were isolated from the marine-derived fungus *Talaromyces* sp. BTBU20213036. Their structures were determined by detailed analysis of HRESIMS, 1D and 2D NMR data, and the absolute configurations were determined on the basis of calculated and experimental electronic circular dichroism (ECD). The antibacterial and antifungal activities of these compounds were tested against Gram-positive—*Staphylococcus aureus*, Gram-negative—*Escherichia coli*, and fungal strain—*Candida albicans*. These compounds showed potential inhibitory effects against *S. aureus* with minimum inhibitory concentrations ranging from 0.195 to 100 µg/mL.

**Citation:** Song, F.; Dong, Y.; Wei, S.; Zhang, X.; Zhang, K.; Xu, X. New Antibacterial Secondary Metabolites from a Marine-Derived *Talaromyces* sp. Strain BTBU20213036. *Antibiotics* **2022**, *11*, 222. https://doi.org/ 10.3390/antibiotics11020222

Academic Editors: William N. Setzer and Jesus Simal-Gandara

Received: 14 January 2022 Accepted: 8 February 2022 Published: 10 February 2022

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**Keywords:** marine-derived fungus; *Talaromyces* sp.; antibacterial; *Staphylococcus aureus*; polyketide
