Marine-derived fungi are assuming an increasingly central role in the search for natural leading compounds with unique chemical structures and diverse pharmacological properties. However, some gene clusters are not expressed under laboratory conditions. In this study, we have found that a marine-derived fungus Aspergillus sp. SYPUF29 would survive well by adding an exogenous nitric oxide donor (sodium nitroprusside, SNP) and nitric oxide synthetase inhibitor (L-NG-nitroarginine methyl ester, L-NAME) in culture conditions. Moreover, using the LC-MS/MS, we initially assessed and characterized the difference in metabolites of Aspergillus sp. SYPUF29 with or without an additional source of nitrogen. We have found that the metabolic pathway of Arginine and proline metabolism pathways was highly enriched, which was conducive to the accumulation of alkaloids and nitrogen-containing compounds after adding an additional source of nitrogen in the cultivated condition. Additionally, the in vitro anti-neuroinflammatory study showed that the extracts after SNP and L-NAME were administrated can potently inhibit LPS-induced NO-releasing of BV2 cells with lower IC₅₀ value than without nitric oxide. Further Western blotting assays have demonstrated that the mechanism of these extracts was associated with the TLR4 signaling pathway. Additionally, the chemical investigation was conducted and led to nine compounds (SF1–SF9) from AS1; and six of them belonged to alkaloids and nitrogen-containing compounds (SF1–SF6), of which SF1, SF2, and SF8 exhibited stronger activities than the positive control, and showed potential to develop the inhibitors of neuroinflammation.

Four novel alkaloids, including three γ-lactam alkaloids (1–3) and one diketopiperazine (4), along with eight previously known compounds (5–12), were isolated from the marine-derived fungus Aspergillus fumigatus SYPHU504. Their structures, including the tentative stereochemical assignments of the side-chain double bonds in 2 and 3, were elucidated through comprehensive spectroscopic analysis and in comparison with the literature’s data. All isolated compounds were evaluated for their anti-leukaemic activities against human leukaemia cell lines K562 and RS4;11 using the MTT assay. Compounds 4, 6, 7, and 9–12 exhibited notable cytotoxic activities against both RS4;11 and K562 cell lines, with IC₅₀ values ranging from 5.02 ± 2.33 to 31.85 ± 0.50 μM. The results of Western blotting and Annexin V-FITC/PI staining elucidated that compounds 4, 7, and 10 could induce apoptosis in both RS4;11 cells and K562 cells.