Xiu-Mei Fu

Bioactive Indole Alkaloids and Phenyl Ether Derivatives from a Marine-Derived Aspergillus sp. Fungus

Two new prenylated indole alkaloids, 17-epi-notoamides Q and M (1 and 2), and two new phenyl ether derivatives, cordyols D and E (9 and 13), together with 10 known compounds (3-8, 10-12, 14) were isolated from a marine-derived Aspergillus sp. fungus. Among them, 1/5 and 2/4 were pairs of epimers. The planar structures and absolute configurations of the new compounds were determined by extensive NMR spectroscopic data as well as CD spectra. The absolute configuration of 3 was confirmed by single-crystal X-ray diffraction analysis for the first time. All isolated metabolites (1-14) and eight synthetic phenyl ether derivatives (12a, 14a-14g) were evaluated for their antibacterial activities in vitro. The polybromide phenyl ether 14g showed pronounced antibacterial activity against Staphylococcus epidermidis with an MIC value of 0.556 μM, stronger than that of the positive control ciprofloxacin (MIC = 3.13 μM).

Antibacterial Bisabolane-Type Sesquiterpenoids from the Sponge-Derived Fungus Aspergillus sp.

Four new bisabolane-type sesquiterpenoids, aspergiterpenoid A (1), (−)-sydonol (2), (−)-sydonic acid (3), and (−)-5-(hydroxymethyl)-2-(2′,6′,6′-trimethyltetrahydro-2H- pyran-2-yl)phenol (4) together with one known fungal metabolite (5) were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated from the sponge Xestospongia testudinaria collected from the South China Sea. Four of them (1–4) are optically active compounds. Their structures and absolute configurations were elucidated by using NMR spectroscopic techniques and mass spectrometric analysis, and by comparing their optical rotations with those related known analogues. Compounds 1–5 showed selective antibacterial activity against eight bacterial strains with the MIC (minimum inhibiting concentrations) values between 1.25 and 20.0 µM. The cytotoxic, antifouling, and acetylcholinesterase inhibitory activities of these compounds were also examined.

Isocoumarin Derivatives and Benzofurans from a Sponge-Derived Penicillium sp. Fungus

Ten new fungal metabolites, including three hydroisocoumarins, penicimarins A-C (1-3), three isocoumarins, penicimarins D-F (6-8), and four benzofurans, penicifurans A-D (11-14), together with four known isocoumarin derivatives (4, 5, 9, 10), were obtained from the sponge-derived fungus Penicillium sp. MWZ14-4, collected from the South China Sea. Their planar structures and relative configurations were elucidated by detailed analysis of spectroscopic data and by comparison with related known compounds. The absolute configurations of 1-4 were assigned by the modified Moshers method and TDDFT ECD calculations together with comparison of their CD spectra. Compound 1 represents a rare naturally occurring isocoumarin derivative with 4-substitution, but no substituent at the 3-position. These compounds were evaluated for antibacterial activities and cytotoxic activities in vitro. Among them, penicifuran A (11) exhibited inhibitory activity against Staphylococcus albus with an MIC value of 3.13 μM.

Antibacterial Anthraquinone Derivatives from a Sea Anemone-Derived Fungus Nigrospora sp.

Chemical investigation of a marine-derived fungus Nigrospora sp., isolated from an unidentified sea anemone, yielded two new hydroanthraquinone analogues, 4a-epi-9α-methoxydihydrodeoxybostrycin (1) and 10-deoxybostrycin (2), together with seven known anthraquinone derivatives (3-9). The structures of the two new compounds were established through extensive NMR spectroscopy as well as a single-crystal X-ray diffraction analysis using Cu Kα radiation. The antibacterial activities of compounds 1-9 and 10 acetyl derivatives (6a, 7a, 8a-8g, 9a) were evaluated in vitro. Compound 6a, the acetylated derivative of 6, exhibited promising activity against Bacillus cereus with an MIC value of 48.8 nM, which was stronger than that of the positive control ciprofloxacin (MIC = 1250 nM). Analysis of the antibacterial screening data for the metabolites and their acetyl derivatives revealed the key structural features required for this activity.

New bisabolane sesquiterpenoids from a marine-derived fungus Aspergillus sp. isolated from the sponge Xestospongia testudinaria.

Three new phenolic bisabolane sesquiterpenoid dimers, disydonols A-C (1-3), and one known compound (S)-(+)-sydonol (4) were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated from the sponge Xestospongia testudinaria collected from the South China Sea. Their structures were elucidated on the basis of comprehensive spectral analysis including 1D and 2D NMR spectra and HR-ESI-MS. These compounds were evaluated for cytotoxic activity against HepG-2 and Caski human tumour cell lines. Among them, compounds 1 and 3 exhibited cytotoxicity against the two cell lines.

Lumazine peptides penilumamides B-D and the cyclic pentapeptide asperpeptide A from a gorgonian-derived Aspergillus sp. fungus.

Three new lumazine peptides, penilumamides B-D (2-4), and one known analogue, penilumamide (1), together with a new cyclic pentapeptide, asperpeptide A (5), were isolated from the gorgonian-derived fungus Aspergillus sp. XS-20090B15. Among them, 2 was obtained from the feeding culture with l-methionine of this strain. All structures were elucidated by spectroscopic methods and chemical derivatization. Compounds 1-4 are rare lumazine peptides, of which 1 and 3 are formed from 2 by oxidation of the l-methionine residue.

Nucleoside derivatives from the marine-derived fungus Aspergillusversicolor

Four nucleoside derivatives (1–4) were isolated from the fungus Aspergillus versicolor derived from the gorgonian Dichotella gemmacea collected in the South China Sea. Their structures were elucidated by comprehensive spectroscopic method of NMR and MS analysis. All isolated metabolites were evaluated for their cytotoxicity, antibacterial activity and lethality towards brine shrimp Artemia salina. Compounds 1/2 exhibited selective antibacterial activity against Staphylococcus epidermidis with an MIC value of 12.5 μM. It should be noted that 1 and 2, whose structures were listed in SciFinder Scholar, had no associated reference. This is the first report about their isolation, structure elucidation and biological activities.

Chinese Marine Materia Medica Resources: Status and Potential

Chinese marine materia medica (CMMM) is a vital part of traditional Chinese medicine (TCM). Compared with terrestrial TCM, CMMM, derived from specific marine habitats, possesses peculiar chemical components with unique structures reflecting as potent pharmacological activities, distinct drug properties and functions. Nowadays, CMMM appears to be especially effective in treating such difficult diseases as cancers, diabetes, cardio-cerebrovascular diseases, immunodeficiency diseases and senile dementia, and therefore has become an important medicinal resource for the research and development of new drugs. In recent years, such development has attracted wide attention in the field of medicine. In this study, the CMMM resources in China were systematically investigated and evaluated. It was found that the historic experiences of Chinese people using CMMM have continuously accumulated over a period of more than 3600 years, and that the achievements of the research on modern CMMM are especially outstanding. By June 2015, 725 kinds of CMMMs from Chinese coastal sea areas have been identified and recorded, covering 1552 organisms and minerals. More than 3100 traditional prescriptions containing CMMMs have been imparted and inherited. However, the number of CMMMs is less than the 8188 terrestrial TCMs, from more than 12,100 medicinal terrestrial plants, animals and minerals. In the future, the research and development of CMMM should focus on the channel entries (TCM drug properties), compatibility, effective ingredients, acting mechanisms, drug metabolism and quality standard. This study reveals the high potential of CMMM development.

Two new eunicellin-based diterpenoids from the South China Sea gorgonian Muricella sibogae Nutting

Two new eunicellin-based diterpenoids, sibogins A (1) and B (2), along with one known analogue (3), and four known 9,10-secosteroids (4–7), were isolated from the gorgonian Muricella sibogae Nutting collected from the South China Sea. The structures of the new compounds were elucidated by comprehensive analysis of spectroscopic data, especially by using 2D NMR spectra. The antifouling activity on barnacle Balanus amphitrite and lethality towards brine shrimp Artemia salina of all the isolated compounds were evaluated.

New 18-oxygenated polyhydroxy steroid from a South China Sea soft coral Sarcophyton sp.

One new 18-oxygenated polyhydroxy steroid, (24S)-ergostan-3β,5α,6β,18,25-pentaol 18,25-diacetate (1), along with five known analogues (2–6), was isolated from a soft coral Sarcophyton sp. collected from the South China Sea. The structure of the new compound (1) was elucidated by 1D NMR, 2D NMR and mass spectrometry. The absolute configuration of 1 was determined by the application of the modified Moshers method. The isolated compounds were assayed for their cytotoxic and antimicrobial activities.