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Marine-derived fungi play an important role in the search for structurally unique secondary metabolites, some of which show promising pharmacological activities that make them useful leads for drug discovery. Marine natural product research in China in general has made enormous progress in the last two decades as described in this chapter on fungal metabolites. This contribution covers 613 new natural products reported from 2001 to 2017 from marine-derived fungi obtained from algae, sponges, corals, and other marine organisms from Chinese waters. The genera Aspergillus (170 new natural products, 28%) and Penicillium (70 new natural products, 11%) were the main fungal producers of new natural products during the time period covered, whereas sponges (184 new natural products, 30%) were the most abundant source of new natural products, followed by corals (154 new natural products, 25%) and algae (130 new natural products, 21%). Close to 40% of all natural products covered in this contribution displayed various bioactivities. The major bioactivities reported were cytotoxicity against different cancer cell lines, antimicrobial (mainly antibacterial) activity, and antiviral activity, which accounted for 13%, 9%, and 3% of all natural products reported. In terms of structural classes, polyketides (188 new natural products, 31%) play a dominant role, and if prenylated polyketides and nitrogen-containing polyketides (included in meroterpenes and alkaloids in this contribution) are taken into account, their total number even exceeds 50%. Nitrogen-containing compounds including peptides (65 new natural products, 10%) and alkaloids (103 new natural products, 17%) are the second largest group.

A new diphenyl ether (1) as well as 20 other compounds were identified from the fermentative extracts of marine-derived fungi Phoma sp. CZD-F11 (Compounds 1-8) and Aspergillus sp. CZD-F18(Compounds 9-21). Their structures were elucidated on the basis of extensive spectroscopic analysis. The broth extracts of the fungi exhibited very good anticancer activity against H1975 cells with 5.62 and 25.8% viability at concentration of 10 μg/mL for Phoma sp. CZD-F11 and Aspergillus sp. CZD-F18, respectively. The inhibitory activity of all compounds against PC-3 cell lines, BRD4 and aromatase were evaluated. The results showed compound 7 exhibited moderate anticancer activity with 66.1% inhibition against PC-3 cell lines at the concentration of 10 μg/mL. Compound 7 and 8 exhibited favourable BRD4 inhibitory activity with 78.5 and 76.4% inhibition at the concentration of 10 μg/mL.

Two new tricycloalternarenes I (1) and J (2), together with five known derivatives (3-7), were isolated from the culture of marine fungus Alternaria sp. The structures were elucidated by a combination of spectroscopic approach ((1)H, (13)C NMR, HMBC, COSY, and NOESY) and the low-temperature (100 K) single-crystal X-ray crystallography analysis. The antimicrobial assays of tricycloalternarenes I (1) and J (2) were tested.