Quan-Xiang Wu

Azonazine, a novel dipeptide from a Hawaiian marine sediment-derived fungus, Aspergillus insulicola.

Azonazine, a unique hexacyclic dipeptide, was isolated from a Hawaiian marine sediment-derived fungus eventually identified as Aspergillus insulicola. Its absolute configuration, 2R,10R,11S,19R, was established using NMR, HRESIMS, and CD data plus insights derived from molecular models. A possible route for its biogenesis is proposed, and biological properties were explored against cancer cell lines and in an NFκB inhibition assay.

Isolation of Secondary Metabolites from the Soil-Derived Fungus Clonostachys rosea YRS-06, a Biological Control Agent, and Evaluation of Antibacterial Activity

The fungus Clonostachys rosea is widely distributed all over the world. The destructive force of this fungus, as a biological control agent, is very strong to lots of plant pathogenic fungi. As part of the ongoing search for antibiotics from fungi obtained from soil samples, the secondary metabolites of C. rosea YRS-06 were investigated. Through efficient bioassay-guided isolation, three new bisorbicillinoids possessing open-ended cage structures, tetrahydrotrichodimer ether (1) and dihydrotrichodimer ether A and B (2 and 3), and 12 known compounds were obtained. Their structures were determined via extensive NMR, HR-ESI-MS, and CD spectroscopic analyses and X-ray diffraction data. Compounds 1-3 are rare bisorbicillinoids with a γ-pyrone moiety. The biological properties of 1-15 were evaluated against six different Gram-positive and Gram-negative bacteria. Bisorbicillinoids, 2-5, and TMC-151 C and E, 14 and 15, showed potent antibacterial activity.

New isocoumarins and alkaloid from Chinese insect medicine, Eupolyphaga sinensis Walker.

Two new isocoumarins (1 and 2), a new alkaloid (3), and a known N-acetyldopamine dimer (4) were isolated from the ethyl acetate extract of Chinese insect medicine Eupolyphaga sinensis. Their structures were elucidated on the basis of detailed spectroscopic investigations, such as 1D- and 2D NMR spectroscopy, as well as by means of HR-MS. The structure of 1 was firmly confirmed by X-ray crystallography, and the absolute configuration was revealed by experimental and computational optical rotation analyses. Cytotoxicities of 1-4 were measured in vitro against 10 selected cancer cell lines.

Talaromycolides A-C, Novel Phenyl-Substituted Phthalides Isolated from the Green Chinese Onion-Derived Fungus Talaromyces pinophilus AF-02.

The green Chinese onion (Allium fistulosum L.), which is widely cultivated and has been naturalized in many places, is an important spice and vegetable in East and Southeast Asia. It is used to treat the common cold in China. In the ongoing search for antibacterial activity in fungi derived from natural, pungently scented vegetables, the secondary metabolites of Talaromyces pinophilus AF-02, which was isolated from the stem of the green Chinese onion, were investigated. The genus Talaromyces (Trichocomaceae) is an important fungal genus because of its ubiquity and the role of many of its species in food and agriculture production. Three new phthalide derivatives, talaromycolides A-C, 1-3; a new long-chain dicarboxylic acid, 11; and 12 known compounds were isolated from methanolic extracts of this fungus. Their structures were determined via extensive NMR, HR-ESI-MS, and CD spectroscopic analyses. Compounds 1-3 are rare phthalide derivatives with a novel linkage position between the phenyl and phthalide moieties. The biological properties of 1-16 were evaluated using six different bacteria, and 1-3, 5, and 11 exhibited significant antibacterial activity in response to some of the tested strains.

The biosynthetic products of Chinese insect medicine, Aspongopus chinensis

A new oxazole (1) was obtained from Chinese insect medicine Aspongopus chinensis, along with three known N-acetyldopamine derivatives (2-4). Their structures were determined on the basis of NMR and ESI-MS analyses. The possible biosynthetic pathways of the isolated compounds are discussed. Cytotoxicities of those compounds against 10 selected cancer cells were measured in vitro.

Pyrone derivatives from the endophytic fungus Alternaria tenuissima SP-07 of Chinese herbal medicine Salvia przewalskii

Three new pyrones, solanapyrones P-R (1-3), were afforded by the extracts of the endophytic fungus Alternaria tenuissima SP-07 isolated from the fresh root of Chinese herbal medicine Salvia przewalskii, along with the known solanapyrones (4-6) and benzopyrones (7-9). Solanapyrones P (1) and Q (2) possess an unprecedented nor-solanapyrone skeleton as natural products. Their structures were determined on the basis of NMR and HR-ESI-MS analysis. The plausible biosynthetic pathways to those unknown compounds were discussed. All the isolated compounds were evaluated for their antibacterial activities against six bacteria.

Triterpenes and steroids from the roots of Scorzonera austriaca.

A new D:B-friedoolean-type triterpene, 3β-acetoxyglutin-5(10)-en-6-oxo (1), together with seventeen known compounds (2-18) was isolated from the roots of Scorzonera austriaca. Their structures were elucidated mainly by NMR and HR-ESI-MS, as well as on comparison with the reported data. Cytotoxicities of compounds 2, 4, 6, 10-14 and 16 against selected cancer cells of human promyelocytic leukemia (HL-60) and human hepatoma (BEL-7404) were measured in vitro.

Sesquiterpenes and diterpenes with cytotoxic activities from the aerial parts of Carpesium humile

Carpesium humile Winkl is an endemic Chinese species and no previous phytochemical studies have been reported for this species. Two new germacranolides (1 and 2) and a new phytane diterpene (5), together with five known compounds (two sesquiterpenoids and three diterpenoids), were isolated from the aerial parts of C. humile. Their structures were elucidated on the basis of extensive spectroscopic analysis. The conformations and absolute configurations of 1 and 2 were established by combinative analysis of NMR, CD exciton chirality, and X-ray crystallography data. Four germacranolides (1-4) showed strong cytotoxic activities, with broad spectrum activities against six human cancer (HepG2, HeLa, HL60, SGC7901, Lewis, and MDA231) cell lines in vitro using MTT assay, with IC50 values from 3.09 to 7.71 μg/mL. Diterpenes (5, 6, and 8) also displayed good cytotoxic activities for selected cancer cell lines, with IC50 values in the range 5.46-8.08 μg/mL.