**4. Conclusions**

Collectively, the mangrove endophytic fungus *Phomopsis asparagi* DHS-48 was effectively stimulated using an HDAC inhibitor (sodium butyrate) to produce two new compounds, named phaseolorin J (**1**) and phomoparagin D (**5**), along with nine known chromones (**2**–**4**) and cytochalasins (**6**–**11**). All the isolates were evaluated for their immunosuppressive and cytotoxic activities. Among them, compounds **1** and **8** showed moderately inhibitory activity against the proliferation of ConA-induced T and LPS-induced B murine spleen lymphocytes, and compound **5** exerted comparative or better in vitro cytotoxicity against the tested human cancer cell lines than the positive control. Thus, this study demonstrates that epigenetic manipulation appears to have a large potential for enhancing the production and/or accumulation of new chemodiversity from mangrove endophytic fungi.

**Supplementary Materials:** The following supporting information can be downloaded at: https:// www.mdpi.com/article/10.3390/md20100616/s1, Figure S1: 1H-NMR of phaseolorin J (**1**). Figure S2: 13C-NMR of phaseolorin J (**1**). Figure S3: DEPT of phaseolorin J (**1**). Figure S4: 1H-1H COSY of phaseolorin J (**1**). Figure S5: HSQC of phaseolorin J (**1**). Figure S6: HMBC of phaseolorin J (**1**). Figure S7: NOSEY of phaseolorin J (**1**). Figure S8: HR-ESI-MS of phaseolorin J (**1**). Figure S9: 1H-NMR of phomoparagin D (**5**). Figure S10: 13C-NMR of phomoparagin D (**5**). Figure S11: DEPT of phomoparagin D (**5**). Figure S12: 1H-1H COSY of phomoparagin D (**5**). Figure S13: HSQC of phomoparagin D (**5**). Figure S14: HMBC of phomoparagin D (**5**). Figure S15: NOSEY of phomoparagin D (**5**). Figure S16: HR-ESI-MS of phomoparagin D (**5**). Figure S17: 1H-NMR of phaseolorin D (**2**). Figure S18: 13C-NMR of phaseolorin D (**2**). Figure S19: HR-ESI-MS of phaseolorin D (**2**). Figure S20: 1H-NMR of chaetochromone B (**3**). Figure S21: 13C-NMR of chaetochromone B (**3**). Figure S22: HR-ESI-MS of chaetochromone B (**3**). Figure S23: 1H-NMR of pleosporalin D (**4**). Figure S24: 13C-NMR of pleosporalin D (**4**). Figure S25: HR-ESI-MS of pleosporalin D (**4**). Figure S26:

1H-NMR of cytochalasin J (**6**). Figure S27: 13C-NMR of cytochalasin J (**6**). Figure S28: HR-ESI-MS of cytochalasin J (**6**). Figure S29: 1H-NMR of cytochalasin J1 (**7**). Figure S30: 13C-NMR of cytochalasin J1 (**7**). Figure S31: HR-ESI-MS of cytochalasin J1 (**7**). Figure S32: 1H-NMR of cytochalasin H (**8**). Figure S33: 13C-NMR of cytochalasin H (**8**). Figure S34: HR-ESI-MS of cytochalasin H (**8**). Figure S35: 1H-NMR of cytochalasin J2 (**9**). Figure S36: 13C-NMR of cytochalasin J2 (**9**). Figure S37: HR-ESI-MS of cytochalasin J2 (**9**). Figure S38: 1H-NMR of cytochalasin J3 (**10**). Figure S39: 13C-NMR of cytochalasin J3 (**10**). Figure S40: HR-ESI-MS of cytochalasin J3 (**10**). Figure S41: 1H-NMR of phomopchalasin D (**11**). Figure S42: 13C-NMR of phomopchalasin D (**11**). Figure S43: HR-ESI-MS of phomopchalasin D (**11**). Figure S44: Overlay of HPLC profiles of EtOAc extracts of *Phomopsis asparagi* DHS-48 cultivated in PDA treated with different epigenetic agents. Figure S45: HPLC spectrum for the purity of tested compounds. Table S1: Gibbs free energiesa and equilibrium populations<sup>b</sup> of low-energy conformers of phaseolorin J (**1**). Table S2: Cartesian coordinates for the low-energy reoptimized MMFF conformers of phaseolorin J (**1**) at B3LYP/6-31G(d,p) level of theory in gas. Table S3: Gibbs free energiesa and equilibrium populations<sup>b</sup> of low-energy conformers of phomoparagin D (**5**). Table S4: Cartesian coordinates for the low-energy reoptimized MMFF conformers of phomoparagin D (**5**) at B3LYP/6-31G(d,p) level of theory in gas. Table S5: The calculated 13C NMR data for isomers of phaseolorin J (**1**). Table S6: DFT-optimized structures and thermodynamic parameters for low-energy conformers of **1**. Table S7: DFT-optimized structures and thermodynamic parameters for low-energy conformers of 8-*epi*-**1**. Table S8: Optimized Z-matrixes of **1** in the gas phase (Å) at B3LYP/6-31G(d) level. Table S9: Optimized Z-matrixes of 8-*epi*-**<sup>1</sup>** in the gas phase (Å) at B3LYP/6-31G(d) level.

**Author Contributions:** J.X. designed and supervised this research, elucidated its structure, and wrote the draft and final revision of the manuscript. T.F. and C.W. performed the isolation, epigenetic manipulation, and validation of experimental data. X.D. and D.C. carried out the biological evaluation. Z.W. measured the NMR spectra. The final revision of the manuscript was revised by all the authors. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (No. 82160675/81973229), the Key Science and Technology Project of Hainan Province (ZDKJ202008/ ZDKJ202018), the Key Research Program of Hainan Province (ZDYF2021SHFZ108), and Guangdong Key Laboratory of Marine Materia Medica Open Fund (LMM2021-4), all of which are gratefully acknowledged.

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