**4. Conclusions**

In summary, three new andrastin-type meroterpenoids (**1**–**3**), one new drimane sesquiterpenoid (**15**) and one sesquiterpenoid J (**14**) that was first isolated from a natural source, together with ten known compounds (**4**–**13**) were isolated from the cultures of the rhizosphere soil of mangrove plant *Avicennia marina* fungus *Penicillium* sp. N-5. Their structures were determined by the analysis of NMR, HR-MS and ECD spectra. All the isolated compounds were investigated for their antimicrobial activities against two phytopathogenic fungi and four bacterial strains. Among them, compounds **1**, **5** and **10** exhibited significant inhibition against *Penicillium italicum* and *Colletrichum gloeosporioides* with MIC values of 6.25, 1.56, 6.25 and 6.25, 3.13, 6.25 μg/mL. Notably, compound **5** showed potential antimicrobial activity against all the strains and the MIC values were lower than 25 μg/mL. Moreover, andrastin-type meroterpenoid antimicrobial activity against phytopathogenic fungi was reported for the first time.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/md20080514/s1, Figure S1: HRESIMS spectrum of compound **1**; Figure S2: 1H NMR spectrum of compound **1**; Figure S3: 13C NMR spectrum of compound **1**; Figure S4: DEPT135 spectrum of compound **1**; Figure S5. HSQC spectrum of compound **1**; Figure S6: H, H-COSY spectrum of compound **1**; Figure S7: HMBC spectrum of compound **1**; Figure S8: NOE spectrum of compound **1**; Figure S9: HRESIMS spectrum of compound **2**; Figure S10: 1H NMR spectrum of compound **2**; Figure S11: 13C NMR spectrum of compound **2**; Figure S12: DEPT135 spectrum of compound **2**; Figure S13: HSQC spectrum of compound **2**; Figure S14: H, H-COSY spectrum of compound **2**; Figure S15: HMBC spectrum of compound **2**; Figure S16: NOE spectrum of compound **2**; Figure S17: HRESIMS spectrum of compound **3**; Figure S18: 1H NMR spectrum of compound **3**; Figure S19: 13C NMR spectrum of compound **3**; Figure S20: HSQC spectrum of compound **3**; Figure S21: H, H-COSY spectrum of compound **3**; Figure S22: HMBC spectrum of compound **3**; Figure S23: NOE spectrum of compound **3**; Figure S24: NOE spectrum of compound **14**; Figure S25: HRESIMS spectrum of compound **15**; Figure S26: 1H NMR spectrum of compound **15**; Figure S27: 13C NMR spectrum of compound **15**; Figure S28. DEPT135 spectrum of compound **15**; Figure S29: HSQC spectrum of compound **15**; Figure S30: H, H-COSY spectrum of compound **15**; Figure S31: HMBC spectrum of compound **15**; Figure S32: NOE spectrum 3M of compound **15**; Figure S33: UV and ECD of compound **1**; Figure S34: UV and ECD of compound **2**; Figure S35: UV and ECD of compound **3**; Figure S36: UV and ECD of compound **14**; Figure S37: UV and ECD of compound **15**.

**Author Contributions:** T.C. performed the experiments and wrote the paper; W.Y. analyzed the data and discussed the results; T.L., Y.Y. and Y.L. participated in the experiments; B.W. and Z.S. reviewed the manuscript; Z.S. designed and supervised the experiments. All authors have read and agreed to the published version of the manuscript.

**Funding:** We thank the National Natural Science Foundation of China (U20A2001, 21877133), GDNRC [2022]35 and the Key-Area Research and Development Program of Guangdong Province (2020B1111030005) for their generous support.

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

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data are contained within the article and Supplementary Material.

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

#### **References**

