Xishan Huang

Asperterpenoid A, a New Sesterterpenoid as an Inhibitor of Mycobacterium tuberculosis Protein Tyrosine Phosphatase B from the Culture of Aspergillus sp. 16-5c

Asperterpenoid A (1), a novel sesterterpenoid with a new carbon skeleton, has been isolated from a mangrove endophytic fungus Aspergillus sp. 16-5c. Its structure was characterized by extensive spectroscopic methods, and the absolute configuration was determined by single crystal X-ray diffraction analysis. Asperterpenoid A (1) exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (mPTPB) with an IC(50) value of 2.2 μM.

Asperterpenols A and B, New Sesterterpenoids Isolated from a Mangrove Endophytic Fungus Aspergillus sp. 085242

Asperterpenol A (1) and asperterpenol B (2), two novel sesterterpenoids with an unusual 5/8/6/6 tetracyclic ring skeleton, were isolated from a mangrove endophytic fungus Aspergillus sp. 085242. The structures were elucidated on the basis of spectroscopic methods and the absolute configurations determined by single-crystal X-ray diffraction analysis. Compounds 1 and 2 inhibit acetylcholinesterase with IC50 values of 2.3 and 3.0 μM, respectively.

Aspterpenacids A and B, Two Sesterterpenoids from a Mangrove Endophytic Fungus Aspergillus terreus H010

Two new sesterterpenoids, aspterpenacids A (1) and B (2), with an unusual carbon skeleton of a 5/3/7/6/5 ring system were isolated from the mangrove endophytic fungus Aspergillus terreus H010. Their structures were elucidated on the basis of spectroscopic methods, single-crystal X-ray diffraction analysis, and electronic circular dichroism calculations. A biogenetic pathway for 1 and 2 is proposed. Both 1 and 2 showed no significant antibacterial activity or cytotoxicity at 50 μM.

Isocoumarins and benzofurans from the mangrove endophytic fungus Talaromyces amestolkiae possess α-glucosidase inhibitory and antibacterial activities

Six new isocoumarins, compounds 1–4 and 14–15, two new benzofurans, 16–17, along with nine known isocoumarin analogues, 5–13 were obtained from the mangrove endophytic fungus Talaromyces amestolkiae YX1. Their structures were elucidated by analysis of spectroscopic data. The absolute configuration of compounds 4, 14 and 15 were determined by the modified Moshers method and comparison of their CD spectra with dihydroisocoumarins described in the literature. The structure of compound 5 was further confirmed by a single-crystal X-ray diffraction experiment using Cu Kα radiation. Compounds 2, 6, 8, and 10 showed α-glucosidase inhibitory activity with IC50 values of 89.4, 17.2, 36.4, and 38.1 μM, respectively. In the antibiotic assay, compounds 16 and 17 exhibited antibacterial activities with MIC values between 25–50 μg mL−1 against the Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Bacillus subtilis.

Polyketides from the Mangrove-Derived Endophytic Fungus Nectria sp. HN001 and Their α-Glucosidase Inhibitory Activity

Four new polyketides: nectriacids A–C (1–3) and 12-epicitreoisocoumarinol (4), together with three known compounds: citreoisocoumarinol (5), citreoisocoumarin (6), and macrocarpon C (7) were isolated from the culture of the endophytic fungus Nectria sp. HN001, which was isolated from a fresh branch of the mangrove plant Sonneratia ovata collected from the South China Sea. Their structures were determined by the detailed analysis of NMR and mass spectroscopic data. The absolute configuration of the stereogenic carbons for compound 4 was further assigned by Mosher’s ester method. All of the isolated compounds were tested for their α-glucosidase inhibitory activity by UV absorbance at 405 nm, and new compounds 2 and 3 exhibited potent inhibitory activity with IC50 values of 23.5 and 42.3 μM, respectively, which were more potent than positive control (acarbose, IC50, 815.3 μM).

New dimeric members of the phomoxanthone family: phomolactonexanthones A, B and deacetylphomoxanthone C isolated from the fungus Phomopsis sp.

Three new phomoxanthone compounds, phomolactonexanthones A (1), B (2) and deacetylphomoxanthone C (3), along with five known phomoxanthones, including dicerandrol A (4), dicerandrol B (5), dicerandrol (6), deacetylphomoxanthone B (7) and penexanthone A (8), were isolated in the metabolites of the fungus Phomopsis sp. HNY29-2B, which was isolated from the mangrove plants. The structures of compounds 1–3 were established on the basis of spectroscopic analysis. All compounds were evaluated against four human cancer cell lines including human breast MDA-MB-435, human colon HCT-116, human lung Calu-3 and human liver Huh7 by MTT assay. The compounds 4, 5, 7 and 8 showed cyctotoxic activities against tested cancer cell lines (IC50 < 10 μM).

A New Anti-acetylcholinesterase α-Pyrone Meroterpene, Arigsugacin I, from Mangrove Endophytic Fungus Penicillium sp. sk5GW1L of Kandelia candel

Arigsugacin I (1), a new α-pyrone meroterpene, along with two known compounds, arigsugacins F (2) and territrem B (3), were isolated from the mangrove endophytic fungus Penicillium sp. sk5GW1L from Kandelia candel. Their structures were identified through mass spectrometry and NMR experiments, and the absolute configuration of compound 1 was further confirmed by low-temperature (100 K) single crystal X-ray diffraction with Cu Kα radiation. The absolute configuration of compound 2 was first reported by using X-ray copper radiation. Compounds 1-3 showed inhibitory activities against acetylcholinesterase with IC50 values of 0.64 ± 0.08 µM, 0.37 ± 0.11 µM, and 7.03 ± 0.20 nM, respectively.

Xylanthraquinone, a new anthraquinone from the fungus Xylaria sp. 2508 from the South China Sea

Xylanthraquinone (1), a new anthraquinone, along with three known compounds, altersolanol A (2), deoxybostrycin (3) and bostrycin (4) was isolated from the fungus Xylaria sp. 2508 from the South China Sea. The structures of these compounds were identified by NMR experiments, and the absolute configuration of compound 1 was further confirmed by single-crystal X-ray diffraction with Cu Kα radiation. Compounds 1–4 did not show inhibitory activities against Mycobacterium tuberculosis protein tyrosine phosphatase B (IC50 values more than 100 μM).

Polyketides with Immunosuppressive Activities from Mangrove Endophytic Fungus Penicillium sp. ZJ-SY2

Nine polyketides, including two new benzophenone derivatives, peniphenone (1) and methyl peniphenone (2), along with seven known xanthones (3–9) were obtained from mangrove endophytic fungus Penicillium sp. ZJ-SY2 isolated from the leaves of Sonneratia apetala. Their structures were elucidated on the basis of MS, 1D, and 2D NMR data. Compounds 1, 3, 5, and 7 showed potent immunosuppressive activity with IC50 values ranging from 5.9 to 9.3 μg/mL.

Altenusin derivatives from mangrove endophytic fungus Alternaria sp. SK6YW3L

Five new altenusin derivatives, compounds 1–5, along with six known analogues 6–11, were isolated from a culture of the endophytic fungus Alternaria sp. SK6YW3L, which was isolated from a fresh fruit of the mangrove plant Sonneratia caseolaris, collected from the South China Sea. Their structures were elucidated by analysis of 1D and 2D NMR and high resolution mass spectroscopic data. The absolute configurations of compounds 1–3 and 5 were assigned by quantum chemical calculations of the electronic circular dichroic (ECD) spectra. Structures of compounds 1 and 4 were further confirmed by single-crystal X-ray diffraction experiments using Cu Kα radiation. All isolated compounds were evaluated for α-glucosidase inhibitory activity, and compounds 2, 3 and 9 exhibited moderate inhibitory activity. The plausible biosynthetic pathways for all the compounds were proposed.