*2.2. Aspergillus sp. from Marine Plants and Their Antimicrobial Activities*

Six new terpenoids were isolated from a seaward fungus *A. alabamensis* (Figure 2). They are asperalacids A-E and 4-hydroxy-5-(6)-dihydroterrecyclic acid A (**4**). Compound **4** and asperalacids A–D (**5**–**8**) showed antimicrobial activities against plant pathogenic fungi *Penicillium italicum*, *Fusarium graminearum* and *F. oxysporum*, as well as *S. aureus* and the Gram-positive bacteria *Bacillus subtilis*. Both MICs of asperalacids A and D against *F. graminearum* were 200 μg/mL. The MIC of asperalacids B and C against *F. oxysporum* were 100 and 100 μg/mL, and 200 and 25 μg/mL against *F. graminearum*, respectively. The MIC of compound **8** against *P. italicum*, *F. graminearum*, *F. oxysporum* and *S. aureus* were 200, 50, 100 and 25 μg/mL, respectively [54].

**Figure 2.** Compounds of *Aspergillus* sp. derived from marine plants.

Eight new benzoic acid-containing alkaloids were isolated and identified from *A. alabamensis*. Among these compounds, asperalins A–F (**9**–**14**) showed moderate or strong inhibitory activities against some fish pathogens, *Streptococcus parauberis*, *S. iniae* and *Edwardsiella ictalurid* (Figure 2). Asperalins C and D showed strong antibacterial activities against *S. aureus*, *S. parauberis* and *S. iniae*, with MIC values of 10.1, 10.1 and 5.0 μM, respectively. Asperalin E had the strongest inhibitory effect on *S. iniae* with an MIC value of 2.2 μM. Notably, the MICs of asperalin F against four Gram-positive bacteria *S. aureus*, *B. subtilis*, *S. parauberis*, *S. iniae* and one Gram-negative bacterium *E. ictalurid* were 21.8, 87.3, 21.8, 43.6 and 10.9 μM, respectively [55].

In conclusion, *Aspergillus* species and its active metabolites from marine plant sources (except mangrove and seagrasses) were summarized. Eleven antimicrobial compounds were identified in the seagrass-derived fungus *A. alabamensis* during 2022 and 2023. Compounds **4**–**8** had a weak inhibitory effect on plant pathogens. However, compounds **11**–**14** showed strong antibacterial effects against *S. aureus*, *S. iniae* and some Gram-positive bacteria.

#### *2.3. Aspergillus sp. from Mangroves and Their Antimicrobial Activities*

Six antibacterial compounds were isolated from the marine fungus *A. brunneoviolaceus* MF180246 (Figure 3). These compounds included asperbrunneo acid (**15**), secalonic acid H (**16**), chrysoxanthone C (**17**), secalonic acid F1 (**18**), asperdichrome (**19**) and penicillixanthone A (**20**). They showed antibacterial activity against *S. aureus* with MIC values of 200, 50, 50, 25, 25 and 6.25 μg/mL [27].

Six polyhydroxy p-terphenyls (asperterphenyllins A–F) were isolated from the endophytic fungus *A. candidus* LDJ-5 in mangroves. Only asperterphenyllin C (**21**) showed antibacterial activity against *Proteus* sp. with an MIC value of 19 μg/mL [56].

Two new heterodimeric tetrahydroxanthones, aflaxanthones A and B (**22** and **23**), were isolated from *A. flavus* QQYZ. These two compounds showed potential antimicrobial activity and broad spectrum against several pathogenic fungi such as *C. albicans* and *F. oxysporum*, with MIC values in the range of 3.13–50 μM. They also showed moderate antibacterial activity against several bacteria such as *B. subtilis* and methicillin-resistant *S. aureus* (MRSA), with MIC values in the range of 12.5–25 μM [57].

In conclusion, *Aspergillus* and its active metabolites from mangroves were summarized. Due to the special geographical environment, mangroves had a wide variety of organisms, which has been thoroughly examined in previous studies of metabolites. Nine antimicrobial compounds were found in three *Aspergillus* strains from mangrove sources. Most of

the compounds showed moderate antimicrobial activities. Among these compounds, compound 20 showed a strong inhibitory effect on *S. aureus*.

**Figure 3.** Compounds of *Aspergillus* sp. derived from mangroves.
