Erwei Li

Pestalotheols A-D, Bioactive Metabolites from the Plant Endophytic Fungus Pestalotiopsis theae

Pestalotheols A-D ( 1- 4 ), four new metabolites, have been isolated from cultures of an isolate of the plant endophytic fungus Pestalotiopsis theae. The structures of these compounds were determined by NMR spectroscopy, and 1 is further confirmed by X-ray crystallography. The absolute configurations of compounds 1 and 3 were assigned by application of the modified Mosher method. Pestalotheol C ( 3) displayed an inhibitory effect on HIV-1 LAI replication in C8166 cells with an EC 50 value of 16.1 microM.

Oxepinochromenones, Furochromenone, and their Putative Precursors from the Endolichenic Fungus Coniochaeta sp.

Six new polyketides including four oxepinochromenones, conioxepinols A-D (1-4), one furochromenone, coniofurol A (5), and one xanthone, conioxanthone A (6), have been isolated from the crude extract of the endolichenic fungus Coniochaeta sp. The absolute configurations of C-7 in 1 and the 7,8-diol moiety in 3 were assigned using the modified Moshers and Snatzkes method, respectively, whereas that of C-8 in 5 was deduced via the circular dichroism data of the [Rh(2)(OCOCF(3))(4)] complex. Compounds 2-4 showed modest cytotoxicity against a small panel of human tumor cell lines.

Polyketides from the Ascomycete Fungus Leptosphaeria sp.

The new polyketides leptosphaerins A-G (1-7) and the known compounds monodictysin B (8), 2-(2,6-dihydroxybenzoyl)-3-hydroxy-5-methylbenzoic acid (9), and 2-(2,6-dihydroxy-4-methylbenzoyl)-6-hydroxybenzoic acid (10) have been isolated from solid cultures of the ascomycete fungus Leptosphaeria sp. The absolute configurations of compounds 1, 2, and 6 were assigned using the modified Mosher method, whereas that of C-2 in 3 was determined via the circular dichroism data of the [Rh(2)(OCOCF(3))(4)] complex. Compound 7 showed antifungal activity against Aspergillus flavus.

Arundinols A-C and arundinones A and B from the plant endophytic fungus Microsphaeropsis arundinis.

Three new ent-eudesmane sesquiterpenoids, arundinols A-C (1-3), one isochroman-1-one, arundinone A (4), and a polyoxygenated benzofuran-3(2H)-one dimer, arundinone B (5), were isolated from the extract of a plant endophytic fungus, Microsphaeropsis arundinis. Their structures were elucidated primarily by NMR experiments, and 1 was confirmed by X-ray crystallography. The absolute configuration of 1 was assigned by X-ray crystallography using Cu Kα radiation, whereas those of the C-11 tertiary alcohols in 2 and 3 were deduced via the circular dichroism data of the in situ formed [Rh(2)(OCOCF(3))(4)] complexes. Arundinone B (5) represents the first dimeric benzofuran-3(2H)-one, showing cytotoxicity against T24 and A549 cells. The co-isolated known compound 6 showed a modest inhibitory effect against Staphylococcus aureus.

Verrucamides A―D, Antibacterial Cyclopeptides from Myrothecium verrucaria

Four new cyclic tetradecapeptides, verrucamides A-D (1-4), have been isolated from the solid-substrate fermentation culture of the ascomycete fungus Myrothecium verrucaria. The structures of these compounds, each featuring six N-methylated amino acid residues, were elucidated primarily by NMR and MS methods. The absolute configurations of 1-4 were assigned by application of Marfeys method on their acid hydrolysates. Compounds 1-4 showed antimicrobial activity against the Gram-positive bacterium Staphylococcus aureus.

Coniochaetones E-I, new 4H-chromen-4-one derivatives from the Cordyceps-colonizing fungus Fimetariella sp.

Five new 4H-chromen-4-one derivatives coniochaetones E-I (1-5), along with the known compounds coniochaetones B (6) and A (7) have been isolated from solid cultures of the Cordyceps-colonizing fungus Fimetariella sp. Their structures were elucidated primarily by NMR spectroscopy and the absolute configurations of compounds 1-3 were assigned using the modified Moshers method. Compound 4 showed weak cytotoxic activity against HeLa cells with IC50 values of 72.8 μM. The co-isolated known compound 6 showed modest inhibitory effects against Aspergilus fumigates, Fusarium oxysporum and Fusarium nivale.

Two new imidazolone-containing alkaloids and further metabolites from the ascomycete fungus Tricladium sp.

Tricladins A and B (1 and 2, resp.), new imidazolone‐containing alkaloids, together with five known metabolites, bacillamides A, B (3 and 4, resp.), 20‐hydroxyaflavinine (5), N‐(2‐phenylethyl)acetamide (6), and Nb‐acetyltryptamine (7), have been isolated from the crude extract of the ascomycete fungus Tricladium sp. The structures of 1 and 2 were elucidated primarily by NMR and MS methods. Compound 2 showed marginal cytotoxicity against MDA‐MB‐231 human breast cancer cells, whereas the known metabolite 4 displayed an inhibitory effect on HIV‐1 replication in C8166 cells.