Zhaokun Li

As special condition-derived microorganisms, mangrove endophytic fungi can produce abundant and active secondary metabolites. In this paper, one strain of Dothiorella sp. ZJQQYZ-1 was isolated from Kandelia candel. As a result, six compounds were obtained from Dothiorella sp. ZJQQYZ-1, including three new benzofuran derivatives dothiofurans A-C (1–3), one new sesquiterpene dothiopene A (4), one new steroid phomosterol C (5), and three known analogs phomosterol B (6), phomosterol A (7), and pergillin (8). Their structures were characterized by extensive spectroscopic analysis, electronic circular dichroism (ECD), and ¹³C NMR calculations. The bioactive assay showed that 7 exhibited significant anti-inflammatory activity with an IC₅₀ value of 4.6 μM. Furthermore, 7 effectivity suppressed the protein expression of inducible nitric oxide synthase (iNOS) in LPS-stimulated RAW264.7 cells.

Five new diterpenes including four diterpenes with 1,2,3,4,4a,5,6,8a-octalin skeleton talaroacids A–D (1–4) and an isopimarane diterpenoid talaromarane A (5) were isolated from the mangrove endophytic fungus Talaromyces sp. JNQQJ-4. Their structures and absolute configurations were determined by analysis of high-resolution electrospray ionization mass spectroscopy (HRESIMS), 1D/2D Nuclear Magnetic Resonance (NMR) spectra, single-crystal X-ray diffraction, quantum chemical calculation, and electronic circular dichroism (ECD). Talaromarane A (5) contains a rare 2-oxabicyclo [3.2.1] octan moiety in isopimarane diterpenoids. In bioassays, compounds 1, 2, 4, and 5 displayed significant anti-inflammatory activities with the IC₅₀ value from 4.59 to 21.60 μM.

Six previously undescribed cytosporone derivatives (phomotones A-E (1–5) and phomotone F (13)), two new spiro-alkanol phombistenes A-B (14–15), and seven known analogs (6–12) were isolated from the mangrove endophytic fungus Phomopsis sp. QYM-13. The structures of these compounds were elucidated using spectroscopic data analysis, electronic circular dichroism (ECD), and ¹³C NMR calculations. Compound 14 features an unprecedented 1,6-dioxaspiro[4.5]decane ring system. All isolates were evaluated for their inhibitory effect on nitric oxide (NO) in LPS-induced RAW264.7 cells. The results showed that compounds 1, 6, 8, and 11 exhibited potent bioactivities by comparing with positive control. Then, compound 1 displayed the anti-inflammatory effect by inhibiting the MAPK/NF-κB signaling pathways. Molecular docking further revealed the possible mechanism of compound 1 interaction with ERK protein.