Antimicrobial secondary metabolites from an endophytic fungus Aspergillus polyporicola.

Two new nucleoside derivatives, kipukasins O (1) and P (2), one new cyclohexenone derivative, arthropsadiol D (5), and one new natural product, (+)-2,5-dimethyl-3(2H)-benzofuranone (6), together with eleven known compounds (3, 4, 7-15), were obtained from the culture broth of the endophytic fungus Aspergillus polyporicola R2 isolated from the roots of Synsepalum dulcificum. Among them, the absolute configuration of compound 5 was determined by quantum chemical calculations of NMR chemical shifts and ECD spectrum. The antimicrobial activities of these compounds were evaluated. Compound 11 exhibited obvious inhibitory activity against MRSA, Staphylococcus aureus, Salmonella typhimurium, Botrytis cinerea, and Fusarium graminearum with MIC values of 4, 4, 4, 32, and 16 µg/mL, respectively. Compound 12 exhibited antibacterial activity against S. typhimurium and MRSA with MIC values of 4 and 16 µg/mL. Compound 6 exhibited antifungal activity against F. graminearum with MIC value of 32 µg/mL.

A new phthalazinone derivative and a new isoflavonoid glycoside from lichen-associated Amycolatopsis sp.

A new phthalazinone derivative, named amycophthalazinone A (1), and a new isoflavonoid glycoside, 7-O-methyl-5-O-α-L-rhamnopyranosylgenestein (2), along with an isoflavonoid glycoside, 7-O-α-D-arabinofuranosyl daidzein (3) firstly found from natural sources, and eight known compounds (4-11), were isolated from the culture broth of the lichen-associated Amycolatopsis sp. YIM 130642. The structures of new compounds were elucidated on the basis of spectroscopic analysis. Compound 1 was the first example of naturally occurring phthalazinone derivative. The antimicrobial activities of all compounds towards five pathogenic strains were evaluated by a broth microdilution assay. Compound 1 exhibited the most potent inhibitory activity against Staphylococcus aureus, Salmonella typhi, and Candida albicans with MIC values of 32, 32, and 64 µg/mL, respectively.

The bioenergetics mechanisms and applications of sulfate-reducing bacteria in remediation of pollutants in drainage: A review.

Sulfate-reducing bacteria (SRB), a group of anaerobic prokaryotes, can use sulfur species as a terminal electron acceptor for the oxidation of organic compounds. They not only have significant ecological functions, but also play an important role in bioremediation of contaminated sites. Although numerous studies on metabolism and applications of SRB have been conducted, they still remain incompletely understood and even controversial. Fully understanding the metabolism of SRB paves the way for allowing the microorganisms to provide more beneficial services in bioremediation. Here we review progress in bioenergetics mechanisms and application of SRB including: (1) electron acceptors and donors for SRB; (2) pathway for sulfate reduction; (3) electron transfer in sulfate reduction; (4) application of SRB for economical and concomitant treatment of heavy metal, organic contaminants and sulfates. Moreover, current knowledge gaps and further research needs are identified.

Polyoxygenated Cyclohexenoids with Promising α-Glycosidase Inhibitory Activity Produced by Phomopsis sp. YE3250, an Endophytic Fungus Derived from Paeonia delavayi.

Seven new polyoxygenated cyclohexenoids, namely, phomopoxides A-G (1-7), were isolated from the fermentation broth extract of an endophytic fungal strain Phomopsis sp. YE3250 from the medicinal plant Paeonia delavayi Franch. The structures of these compounds were established by spectroscopic interpretation. The absolute configurations of compounds 1 and 4 were confirmed by X-ray crystallographic analysis and chemical derivative approach. All isolated compounds showed weak cytotoxic activities toward three human tumor cell lines (Hela, MCF-7, and NCI-H460) and weak antifungal activities against five pathogenic fungi (Candida albicans, Aspergillus niger, Pyricularia oryzae, Fusarium avenaceum, and Hormodendrum compactum). In addition, compounds 1-7 showed a promising α-glycosidase inhibitory activity with IC50 values of 1.47, 1.55, 1.83, 2.76, 2.88, 3.16, and 2.94 mM, respectively, as compared with a positive control of acarbose (IC50 = 1.22 mM).

Antiviral anthraquinones and azaphilones produced by an endophytic fungus Nigrospora sp. from Aconitum carmichaeli.

A new hydroanthraquinone derivative, 6-O-demethyl-4-dehydroxyaltersolanol A (1), and two new azaphilones, 8,11-didehydrochermesinone B (6) and (7S)-7-hydroxy-3,7-dimethyl-isochromene-6,8-dione (8), along with five known analogues (2-5 and 7), were isolated from the culture broth of Nigrospora sp. YE3033, an endophytic fungus obtained from Aconitum carmichaeli. Their structures were elucidated on the basis of spectroscopic analyses. Biological activity test indicated that compounds 1-3, and 7 exhibited the inhibitory effects on influenza viral strain of A/Puerto Rico/8/34 (H1N1) with the IC50 values of 2.59, 8.35, 7.82, and 0.80µg/mL, respectively, while the low cytotoxicity of 7 with the CC50 value of 184.75µg/mL, displaying a promising potential of 7 in the development of anti-influenza A virus drugs.

Identification of volatiles in leaves of Alpinia zerumbet 'Variegata' using headspace solid-phase microextraction-gas chromatography-mass spectrometry.

Alpinia zerumbet 'Variegata' is an aromatic medicinal plant, its foliage producing an intense, unique fragrant odor. This study identified 46 volatile compounds in the leaf tissue of this plant using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The major compounds included 1, 8-cineole (43.5%), p-cymene (14.7%), humulene (5.5%), camphor (5.3%), linalool (4.7%), (E)-methyl cinnamate (3.8%), gamma-cadinene (3.3%), humulene oxide II (2.1%) and a-terpineol (1.5%). The majority of the volatiles were terpenoids of which oxygenated monoterpenes were the most abundant, accounting for 57.2% of the total volatiles. Alcohols made up the largest (52.8%) and aldehydes the smallest (0.2%) portions of the volatiles. Many bioactive compounds were present in the volatiles.

Bioactive metabolites produced by the endophytic fungus Phomopsis sp. YM355364.

A new compound, 16-acetoxycytosporone B (1), along with four known ones, dankasterone A (2), dankasterone B (3), 3beta,5alpha,9alpha-trihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (4), and cyclonerodiol oxide (5), were isolated from Phomopsis sp. YM355364, an endophytic fungus of Aconitum carmichaeli. Their structures were characterized by spectral analysis. Compound 2 exhibited significant inhibitory activity against influenza A/Thailand/Kan353/2004(H5N1) pseudovirus with all IC50 value of 3.56 microM. Compounds 1, 2, and 4 showed either moderate or weak antifungal activities against four pathogenic fungi.

Cyclonerol derivatives from Trichoderma longibrachiatum YM311505.

A new sesquiterpene, 10,11-dihydrocyclonerotriol (1), together with two known compounds, catenioblin C (2) and sohirnone A (3), were isolated from Trichoderma longibrachiatum YM311505, an endophytic fungus of Azadirachta indica. Their structures were characterized and identified by spectral analysis. Compounds 1-3 exhibited antifungal activities against Pyricularia oryzae and Candida albicans.

[Studies on chemical constituents from stem bark of Trewia nudiflora].

OBJECTIVE: To study the chemical constituents from the stem bark of Trewia nudiflora. METHOD: The chemical constituents were isolated by silica gel and sephadex LH - 20 column chromatography, and the structures were elucidated by means of spectral analysis. RESULT: Ten compounds were obtained from EtOAc fraction of EtOH extract and identified as stigmast-4-en-6beta-ol-3-one (1), stigmast-4-en-6alpha-ol-3-one (2), 7beta-hydroxysitosterol (3), 7alpha-hydroxysitosterol (4), schleicheol 2 (5), taraxerone (6), abbeokutone (7), beta-hydroxypropiovanillone (8), o-vanillyl alcohol (9), glycerol monopalmitate (10). CONCLUSION: Compounds 1-5 and 7-9 were isolated from this plant for the first time.

A new ellagic acid glycoside from Paeonia delavayi.

A new ellagic acid glycoside, 4'-O-methylellagic acid 4-O-beta-D-glucopyranoside (1), was isolated from the root cortex of Paeonia delavayi. The structure was elucidated on the basis of spectroscopic methods.

Chemical constituents from the stem bark of Trewia nudiflora L. and their antioxidant activities.

Three new compounds, namely, (+)-dihydrodehydrodiconiferyl alcohol 4- O- beta-(6''- O-galloyl)-glucopyranoside ( 1), 4,4'- O-dimethylellagic acid 3-(2''- O-acetyl)- alpha-rhamnopyranoside ( 2), and ethyl O- beta-(6'-galloyl)-glucopyranoside ( 3), together with eleven known ones, were isolated from the stem bark of Trewia nudiflora. Their structures were elucidated by means of 1D, 2 D NMR and HR-MS analyses. The antioxidant activities of these compounds were evaluated with the DPPH radical-scavenging assay. Compound 1 showed significant antioxidant activity. In addition, compounds 1, 2 and 3 rescued the H (2)O (2)-induced PC12 cell death at 0.4 microM in the MTT assay.

Monoterpene glycosides from Paeonia delavayi.

A new monoterpene glycoside, 4-O-methyl-4''-hydroxy-3''-methoxy-paeoniflorin (1), was isolated from the root cortex of Paeonia delavayi along with the known paeoniflorin, oxypaeoniflorin, benzoylpaeoniflorin, benzoyloxypaeoniflorin, albiflorin and a paeonilactone-A.

Monoterpenoid derivatives from Paeonia delavayi.

Three new monoterpene glycosides, 4-O-ethylpaeoniflorin (1), 6'-O-benzoyl-4''-hydroxy-3"-methoxy-paeoniflorin (2), 6'-O-benzoylalbiflorin (3), and a new monoterpenoid, 9-hydroxy-paeonilactone-A (4) were isolated from the root cortex of Paeonia delavayi. Their structures were elucidated on the basis of spectral methods.

[Anti-gastric ulcer sesquiterpene lactone glycosides from Crepis napifera].

AIM: The anti-gastric ulcer constituents from the roots of Crepis napifera (Franch) Babc (Compositae) were studied. METHODS: Solvent partition, Si gel and Rp-18 column chromatography, crystallization and spectral methods were used to extract, isolate and identify two compounds. The activity of compound 1 was tested on the rat stomach by determining the effect on aspirin-induced gastric lesions and on histamine-stimulated gastric acid secretion. RESULTS: Two sesquiterpene lactone glycosides, taraxinic acid-1'-O-beta-D-glucopyranoside (1) and 11,13-dihydro-taraxinic acid-1'-O-beta-D-glucopyranoside (2) were obtained. Compound 1 at the dose of 80 mg.kg-1 p.o. inhibited significantly the development of aspirin-induced gastric lesions in the rat and at an i.v. dose of 70 mg.kg-1 did not affect histamine-stimulated gastric acid secretion in the lumen-perfused rat stomach. CONCLUSION: Compound 1 is the active component of the plant which protects gastric mucosa and exhibits anti-gastric ulcer action.