New polyketides and sesquiterpenoids from the deep-sea sulphide-derived fungus Phoma sp. 3A00413.

Phoma fungi are known to produce a diverse range of natural products which possess various biological activities such as antifungal, antimicrobial, insecticidal, cytotoxic, and immunomodulatory effects. In our present study, we have isolated two novel polyketides (1 and 3), one new sesquiterpenoid (2), and eight known compounds (4-11) from the culture of Phoma sp. 3A00413, a deep-sea sulphide-derived fungus. The structures of compounds 1-3 were elucidated using NMR, MS, NMR calculation, and ECD calculation. In vitro antibacterial activities of all the isolated compounds were evaluated against Escherichia coli, Vibrio parahaemolyticus vp-HL, Vibrio parahaemolyticus, Staphylococcus aureus, Vibrio vulnificus, and Salmonella enteritidis. Compounds 1, 7, and 8 exhibited weak inhibition against Staphylococcus aureus growth, while compounds 3 and 7 showed weak inhibition against Vibrio vulnificus growth. Importantly, compound 3 demonstrated exceptional potency against Vibrio parahaemolyticus, with a minimum inhibitory concentration (MIC) of 3.1 µM.

Asperochratides A-J, Ten new polyketides from the deep-sea-derived Aspergillus ochraceus.

Ten new C9 polyketides (asperochratides A-J, 1-10) and 14 known miscellaneous compounds (11-24) were isolated from the deep-sea-derived fungus Aspergillus ochraceus. Structures of the new compounds were elucidated by extensive spectroscopic analyses, modified Mosher's method, Mo2(OAc)4 induced circular dichroism (ICD) experiments, and ECD calculations. Structurally, compounds 1-11 and 16-18 share the same polyketide origin of the skeleton and belong to aspyrone co-metabolites. All isolates were tested for cytotoxic, anti-food allergic, anti-H1N1 virus, anti-microbe, and anti-inflammatory activities in vitro. Results showed that compounds 5-8 and 13-17 exerted significant cytotoxic effects on BV-2 cell line, and compound 16 showed the potential of anti-inflammatory activities.

Saccharopolytide A, a new cyclic tetrapeptide with rare 4-hydroxy-proline moieties from the deep-sea derived actinomycete Saccharopolyspora cebuensis MCCC 1A09850.

A genome mining analysis on the deep-sea derived actinomycete Saccharopolyspora cebuensis MCCC 1A09850 indicated its potential to produce polypeptides. Accordingly, a systematic chemical investigation was conducted, which resulted in the isolation of one new cyclic tetrapeptide (saccharopolytide A, 1) and two known polyketides (2, 3) along with six other miscellaneous compounds (4‒9). Mainly by analysis of the 1D, 2D NMR and MS data, the chemical structure of saccharopolytide A was established as cyclo-(l-Leu-4-hydroxy-l-Pro-l-Phe-4-hydroxy-l-Pro). All isolates were evaluated for anti-allergic and anti-tumor bioactivities. Indol-3-carbaldehyde (4) showed weak anti-allergic effect with IC50 value of 55.75 µg/mL. And 2 showed weak anti-proliferative activity against Hela and H1299 tumor cell lines. Our results consolidate the potential of deep-sea-derived microorganisms to produce structurally interesting compounds.