D from the sea-sediment 25-Hydroxycholesterol Metabolic Enzyme/Protease derived Cladosporium sp. acetone extract by Huang et al. in 2018. Compounds 146 are uncommon 3-acyltetramic acids, obtaining at C-3 from the pyrrolidine-2,4-dione core, a six-membered lactone ring, and hexyl-enic alcohol chain. They showed no clear AchEI activity inside the modified Ellman’s enzyme assay [58]. Moreover, they displayed no anti-biofilm effect against C. albicans and S. aureus inside the broth micro-dilution process and no cytotoxic impact towards HL60, HepG-2, and MCF-7 cell lines within the CCK8 assay [58]. three.2. Diketopiperazines Diketopiperazines (DKPs) are cyclic dipeptides, consisting of two amino acids with or without having further structural modifications within the DKPs nucleus [108]. Their most important skeleton comprises a six-membered piperazine nucleus made in the double condensations among two amino acids [129,130]. The formation of peptide bonds in DKPs are catalyzed mostly by cyclodipeptide synthases (CDPSs) and non-ribosomal peptide synthetases (NRPSs) [131]. They possessed exciting bioactivities for instance anti-Alzheimer, antimicrobial, antiviral, microtubule polymerization inhibitory, antitumor, anti-quorum-sensing, and haemosuppressor [129,130,132]. Cyclo-(Val-Pro) (32) and cyclo-(Phe-Pro) (33) were Bafilomycin C1 Membrane Transporter/Ion Channel separated from the EtOAc extract of Cladosporium sp. F14 isolated from seawater and investigated for their anti-larval activity at conc. 50 /mL towards Bugula neritina and Balanus amphitrite larvae within the settlement inhibition assays [60] (Figure six). They inhibited B. neritina settlement (EC50 70.43 and 200 /mL, respectively) and B. amphitrite settlement (EC50 68.57 and 37.82 /mL, respectively). Moreover, 32 and 33 clearly prohibited L. hongkongensis growth (IZDs 8 mm and MICs 200 and 200 /mL, respectively), when compared with streptomycin (MIC 250 /mL). The MICs of 33 towards Ruegeria sp. and M. luteus were 200 and 100 /mL, respectively, compared to streptomycin (MIC 500 and 250 /mL, respectively) [60]. However, thio-diketopiperazine derivatives, cladosporins A (36) and B (37), and haematocin (38) purified in the sediment-derived Cladosporium sp. have been moderately cytotoxic towards HepG2 cell line (IC50 48, 21, and 42 /mL, respectively) [62]. 3.3. Alkaloids Fungal alkaloids are nitrogen-containing metabolites that happen to be derived from amino acid metabolism and also the mevalonate pathway [133]. Several research reported the detection of different classeses of alkaloids from marine-derived fungi such as pyrrolidine, indole, pyrrolizidine, quinazoline, quinoline, and purine classes [13436]. These metabolites have shown broad biological activities: cytotoxic, anti-inflammatory, antioxidant, antibacterial, antifungal, antiviral, protease inhibitory. Consequently, they could have a potential for the development of revolutionary therapies [13436]. Inside the current perform, 49 alkaloids, belonging to distinctive classes have already been reported. Among them, 27 alkaloids were reported from unidentified Cladosporium species.Mar. Drugs 2021, 19,35 ofFigure 4. Tetramic acid derivatives 164.Mar. Drugs 2021, 19,36 ofFigure 5. Tetramic acid derivatives 250.Mar. Drugs 2021, 19,37 ofFigure six. Diketopiperazine derivatives 318.The glyantrypine-type alkaloids, 425, have been separated from Cladosporium sp. PJX-41 isolated from mangrove and assessed for anti-H1N1 activity working with CPE (cytopathic effect) inhibition assay (Figures 7 and 8). Compounds 45, 49, 513, and 55 displayed remarkable anti-H1N1 activities (IC50 values ranged from 82 to 89), in comparison with ribavirin (.