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Papers by dang cong quang

There is increasing insight into how household poverty in rural and peri-urban areas is affected ... more There is increasing insight into how household poverty in rural and peri-urban areas is affected by developments in the markets for fruit, vegetables and flowers. This study extends the knowledge, and feeds into the debate on agricultural growth policies. Based on a positive outlook on the growth of horticultural production and distribution and marketing in the low income countries of Uganda and Vietnam, this paper asks whether poor and vulnerable groups in society share in the benefits of the foreseen economic expansion. Primary survey data is collected on the differentiated position of low-income households in different supply structures (with varying levels of vertical coordination) and markets (national, regional and international markets). The data support the following hypotheses: (i) For many resource-poor agents, horticulture-related activities make substantial contributions to their livelihood security certainly in the short term. (ii) Farming, trading services, small-scale...

Natural Product Communications, 2010

A new isoquinoline alkaloid, ampullosine (3-methyl-isoquinoline-6-carboxylic acid, 1), was isolat... more A new isoquinoline alkaloid, ampullosine (3-methyl-isoquinoline-6-carboxylic acid, 1), was isolated from Sepedonium ampullosporum and characterized by spectroscopic analysis and chemical reactions. This compound is responsible for the deep yellow color of the culture fluid of this species. Moreover, the known compounds sepedonin (2) and anhydrosepedonin (3) were detected. Twelve strains belonging to eight species of Sepedonium have been screened for these three metabolites by LC/ESI-SRM (selected reaction monitoring). Ampullosine (1) could be detected in almost all species in Sepedonium, but not in the phylogenetically more distant species S. brunneum and S. tulasneanum. Anhydrosepedonin (3) showed antifungal activity against the phytopathogenic fungus Cladosporium cucumerinum.

Natural Product Communications, 2014

Two new phenylbenzofuran-type stilbenoids named stemofurans X and Y (1, 2) were isolated from the... more Two new phenylbenzofuran-type stilbenoids named stemofurans X and Y (1, 2) were isolated from the roots of Stemona pierrei and S. tuberosa, respectively, together with ten known compounds. These compounds were stemanthrenes B-C (3, 4), (+)-syringaresinol (5), maistemonine (6), isomaistemonine (7) and sesamin (8) from S. pierrei, and stemophenanthrenes A-C (9–11) and isopinosylvin A (12) from S. tuberosa. Stemofurans X-Y (1, 2) showed moderate cytotoxicity against the four cancer cell lines KB (human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma), and Hep-G2 (hepatocellular carcinoma).

Natural Product Communications, 2007

Fruiting bodies collected in the field during the vegetation period in different developmental st... more Fruiting bodies collected in the field during the vegetation period in different developmental stages and mycelial cultures of 50 representatives of xylariaceous fungi were tested for antimicrobial and nematicidal activities, and 50 of their characteristic metabolites were studied for comparison. Furthermore, analytical HPLC profiling using diode array and electrospray mass spectrometric detection was performed to identify and quantify the major constituents, revealing that up to 10% of the dry fruiting body biomass may be composed of secondary metabolites. In several species, significant antimicrobial effects were noted upon incubation of the fruiting bodies in an agar diffusion assay, i.e., without any need for extraction and concentration of active constituents. These results suggest that most of the characteristic constituents of subfamily Hypoxyloideae (i.e. Hypoxylon and related genera) are involved in non-specific defense reactions that underwent specific permutations in the ...

International Journal of the Commons, 2009

Payments for environmental services in upper-catchments of Vietnam 65 agricultural households of ... more Payments for environmental services in upper-catchments of Vietnam 65 agricultural households of the upper-catchments in Northern Vietnam. We focus our attention on households identified as the poorest in the upper-catchment areas, i.e. those with a small endowment of productive land, limited access to water for irrigation, and low access to markets. We find that farmers are unlikely to participate in a voluntary land retirement program unless they are 'compensated' for the loss in food production and a 'forced' set aside program is likely to generate an overall negative impact on both poverty and environmental protection. Development and dissemination of improved technologies that increase food yields is a complementary strategy to promote environmental protection.

Phytochemistry, 2003

Three benzoyl p-terphenyl derivatives named thelephantins A, B and C were isolated from the ethyl... more Three benzoyl p-terphenyl derivatives named thelephantins A, B and C were isolated from the ethyl acetate extract of fruit bodies of the Thelephoraceous Basidiomycete Thelephora aurantiotincta. Their structures were elucidated by analysis of high-resolution 2D NMR, MS, IR and UV spectra.

The Chemical Record, 2006

In the course of our investigation on biologically active substances from inedible mushrooms in J... more In the course of our investigation on biologically active substances from inedible mushrooms in Japan, Germany, and Vietnam, we studied the chemical constituents of 22 species belonging to five families: Scutigeraceae, Polyporaceae, Xylariaceae, Thelephoraceae, and Paxillaceae. Various types of chemical substances were purified and characterized based on the modern spectroscopic methods and also on chemical reactions. These metabolites have shown a broad activity in many biological systems, such as antimicrobial, nematicidal, inhibition of NO production, antihuman immunodeficiency virus, tumor necrosis factor-α, and antioxidant activities. These isolated metabolites did not only show interesting activities, but also are employed as chemical markers supported for chemosystematics of these families. This review paper deals with the chemical constituents of 22 species, their biological activities, and also a discussion on chemosystematics.

Planta Medica, 2005

Four new azaphilones named multiformins A - D together with a known compound 4 : 5:4&... more Four new azaphilones named multiformins A - D together with a known compound 4 : 5:4':5'-tetrahydroxy-1 : 1'-binaphthyl were isolated from the methanolic stromatal extract of the xylariaceous ascomycete Hypoxylon multiforme. Their absolute structures were characterised by 2D-NMR, UV, IR, mass and CD spectroscopy. Multiformins A - D showed strong and apparently non-selective antimicrobial activity.

Phytochemistry, 2005

Investigation of the methanolic extract of the inedible mushroom Fomitopsis spraguei (Polyporacea... more Investigation of the methanolic extract of the inedible mushroom Fomitopsis spraguei (Polyporaceae) led to the isolation of five lanostane-type triterpenoids (1-5): three new compounds named fomitopsins A-C (2-4), and two known compounds, quercinic acid C (1) and 3alpha-carboxyacetyl-12beta-hydroxyquercinic acid (5). Their structures were determined by 2D NMR, MS, IR, UV spectra, and X-ray crystallographic analyses. An X-ray crystal structure analysis of quercinic acid C (1) established its stereochemistry as 3R,12R-dihydroxy-24R-methyl-23-oxo-25S-lanost-8-en-26-oic acid.

Phytochemistry, 2005

Other natural products U 0800 Cohaerins A and B, Azaphilones from the Fungus Hypoxylon cohaerens,... more Other natural products U 0800 Cohaerins A and B, Azaphilones from the Fungus Hypoxylon cohaerens, and Comparison of HPLC-Based Metabolite Profiles in Hypoxylon sect. Annulata.

Natural Product Research, 2013

The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Journal of Natural Products, 2002

Four compounds, daldinone A (1), daldinone B (2), daldiniapyrone (4-methoxy-5-carbomethoxy-6-pent... more Four compounds, daldinone A (1), daldinone B (2), daldiniapyrone (4-methoxy-5-carbomethoxy-6-pentyl-2H-pyran-2-one, 3), and daldinialanone (22R-hydroxylanosta-7,9(11),24-trien-3-one, 4), were isolated from an ethyl acetate extract of fruit bodies of Daldinia concentrica collected in Europe. In addition, 11 known compounds, 4:5:4′:5′-tetrahydroxy-1:1′-binaphthyl (5), 3,4,5-trihydroxy-1-tetralone (6), (+)-orthosporin (7), curuilignan D (8), (22E)-cholesta-4,6,8(14),22-tetraen-3-one (9), 3 ,22-dihydroxylanosta-7,9(11),24-triene (10), concentricol (11), concentricol B (12), concentricol C (13), concentricol D (14), and phenochalasin B (15), were obtained. The structures of the new compounds were elucidated by 2D NMR, MS, IR, and UV spectra and by X-ray crystallographic analysis. The absolute configurations of 1 and 4 were determined by CD spectroscopy and the modified Mosher's method, respectively. The chemotaxonomic relevance of the compounds obtained in this investigation is discussed.

Journal of Natural Products, 2003

A large amount of sex pheromones of the European spider Linyphia triangularis, 3R-hydroxybutyric ... more A large amount of sex pheromones of the European spider Linyphia triangularis, 3R-hydroxybutyric acid (1), its dimer 3R-(3R-hydroxybutyryloxy)butyric acid (2), and trimer 3R-[3R-(3R-hydroxybutyryloxy)butyryloxy]butyric acid (3) were isolated from the EtOAc extract of the Japanese inedible mushroom Hypoxylon truncatum. Anderson 1 isolated 3,4-dihydro-8-hydroxy-3-methylisocoumarin from the inedible mushroom Hypoxylon truncatum. Later Uebler 2 and Kern 3 also reported the same compound as a trail pheromone component of the ants Camponotus silvicola, C. rufipes, and Lasius fuliginosus, respectively. These results opened the avenue for research on compounds occurring in both insects and mushrooms. Recently, we investigated the chemical constituents of the Japanese H. truncatum and isolated a novel perylenequinone, truncatone. 4 Further fractionation of the ethyl acetate extract has now resulted in the isolation of monomeric 3R-hydroxybutyric acid (1), its dimer 3R-(3Rhydroxybutyryloxy)butyric acid (2), and trimer 3R-[3R-(3Rhydroxybutyryloxy)butyryloxy]butyric acid (3), which are known to be sex pheromones of the spider Linyphia triangularis (Clerck) and related species. 5 The EtOAc extract of H. truncatum was subjected to SiO 2 and Sephadex LH-20 column chromatography to give 3-hydroxybutyric acid (1) and a mixture of compounds 2 and 3. On the basis of the IR spectral evidence to support the presence of a carboxylic acid group (2400-3600 cm-1), samples of compound 1 and the mixture of 2 and 3 were methylated, then purified using preparative HPLC to give compounds 4, 5, and 6 as methylated derivatives of 1, 2, and 3, respectively. On the basis of analyses of IR, 1 H and 13 C NMR, and MS spectra and comparisons of the spectral data with those of authentic samples and reported spectral data, 6,7 their stuctures were determined to be 3-hydroxybutyric acid methyl ester (4), the dimer 3-(3-hydroxybutyryloxy)butyric acid methyl ester (5), and the trimer 3-[3-(3-hydroxybutyryloxy)butyryloxy]butyric acid methyl ester (6). To determine the absolute configurations of compounds 1, 2, and 3, they were each converted to 3-acetoxybutyric acid methyl ester (7), which was analyzed by GC-MS on a chiral column. Compound 1 was methylated with trimethylsilyldiazomethane and acetylated to afford compound 7. A mixture of dimer 5 and trimer 6 was saponified with potassium hydroxide in methanol, followed by methylation and acetylation to yield 7. Compound 7 was analyzed by gas chromatography-mass spectroscopy (GC-MS) on a chiral column with authentic samples (each 3R-and 3Sacetoxybutyric acid methyl ester, which was derived from 3R-and 3S-hydroxybutyric acid, respectively) to give the chromatograms shown in Figure 2. Consequently, the configurations of all asymmetric carbons of 1, 2, and 3 were established to be R.

Journal of Natural Products, 2004

Fractionation of the methanol extract of the fruit bodies of the xylariaceus ascomycete Hypoxylon... more Fractionation of the methanol extract of the fruit bodies of the xylariaceus ascomycete Hypoxylon rubiginosum resulted in the isolation of three new azaphilone derivatives named rubiginosins A-C (1-3) and a new fatty acid named rubiginosic acid (4), together with three known compounds, entonaemin A (5), daldinin C (6), and orsellinic acid. Their structures were elucidated by 2D NMR, MS, IR, and UV spectra and chemical reaction. The absolute configuration of compound 3 was established by CD spectroscopy. The structure of 4 was confirmed by X-ray crystallographic analysis.

Journal of Natural Products

Journal of Natural Products, 2006

Carneic acids A and B (1, 2) are polyketide antibiotics structurally related to phomopsidin. They... more Carneic acids A and B (1, 2) are polyketide antibiotics structurally related to phomopsidin. They were isolated as major constituents of the stromata of Hypoxylon carneum, a species that had shown a highly specific secondary metabolite profile in a survey of xylariaceous ascomycetes based on HPLC profiling. Their chemical structures were elucidated by a combination of spectroscopic methods and by preparation of derivatives. An X-ray crystal structure of the dinitrobenzoate of carneic acid B methyl ester (8) was obtained, even allowing for determination of its absolute structure. The carneic acids showed weak antibacterial and moderate antifungal activities in the serial dilution assay against selected microbial organisms. They appear to be species-specific marker molecules in H. carneum from different geographic regions, but do not constitute major metabolites of more than 100 species of Xylariaceae. Their biological and chemotaxonomic significance is discussed. Hypoxylon carneum Petch (Xylariaceae, Figure 1) is a woodinhabiting ascomycete, first described from Sri Lanka 1 and later also reported from the United States, Venezuela, New Zealand, 2 and France. 3 It is one of the few species in the large genus Hypoxylon that is not restricted to certain geographic areas, but was proven to have a truly cosmopolitan distribution, being present in temperate as well as in subtropical and tropical climates. As judged from our field studies on its occurrence in southwestern France, 3 it is apparently not rare. Because of its morphological similarity to the common H. rubiginosum and other related species, it has probably been frequently overlooked. 3 The most striking feature to discriminate H. carneum from its relatives can be readily determined without any need for detailed microscopic studies: its pigments in KOH are faint purple, while those of related species yield dense orange, brown, or yellowish pigments in KOH. 3 Also, H. carneum has faintly yellowish granules beneath the stromata surface, whereas those of its allies are orange, red, or brown. These features are due to the presence of different secondary metabolites, which was established by a HPLC profiling study of about 2500 specimens and cultures of Hypoxylon and related Xylariaceae. 3-6 Recent evidence for the molecular taxonomy of Hypoxylon and allies 7 revealed that the closest affinities of H. carneum (i.e., the clades H1 and H2 as described in ref 7), as inferred from a molecular phylogenetic study, are with species that preferably contain azaphilones. These clades comprise, aside from some taxa that were not yet studied for HPLC profiles, for example, H. cercidicola, H. petriniae, 3 H. perforatum, H. pilgerianum, and H. rubiginosum. 3,4 H. carneum strongly differed from all of these species in its HPLC profile. The common stromatal azaphilone pigments of many Hypoxylon spp. of clades H1 and H2 as described in ref 7 (i.e., mitorubrins, rubiginosins, and hypomiltin 3,4) were not detected by HPLC-MS, and instead 4:5:4′:5′-tetrahydroxy-1:1′binaphthyl (BNT, 3) and a series of apparently species-specific but yet unknown metabolites were detected as major components. 4 Interestingly, only BNT (3) and daldinins, but no mitorubrin-type azaphilones, were also reported previously from the core species of another side branch of clade H1, i.e., H. fuscum.

Journal of Natural Products, 2008

Three novel alkaloids (1-3), named pyriferines A-C, were isolated from fruiting bodies of Pseudob... more Three novel alkaloids (1-3), named pyriferines A-C, were isolated from fruiting bodies of Pseudobaeospora pyrifera. They possess an unusual eight-membered N/O-acetal ring, derived from L-glutamic acid, that is connected to an enolized 1,3-diketo moiety. The structures were determined by spectroscopic methods, and the absolute configuration of the glutamic acid moiety was established using GC-MS after Mosher-type derivatization. The fungal genus Pseudobaeospora (Tricholomataceae) is very rare and only described for Europe and North America. Thirteen species are known, but their chemical constituents are unknown. 1 The genus was first established by Singer 2,3 and recently generically circumscribed by Bas. 1,4 The species Pseudobaeospora pyrifera Bas & L. Krieglst. (Agaricales) investigated herein was described in 1998. 5 P. pyrifera is characterized by a 0.5-2.5 cm wide cap and a 1-3.5 cm long and 0.3-0.5 cm broad stipe. Cap and stem are pruinose sordid pink to pruinose vinaceous; the lamellae are rather dark reddish to violaceous pink colored. This little species grows on the ground in more or less moist areas (Pruno-Fraxinetum woods with Alnus, Prunus padus, Fraxinus). P. pyrifera is characterized by a greenish-blue to brownish-green reaction of the pileipellis with KOH solution. In this work, we describe the isolation and structural characterization of three novel unusual alkaloids that possess unprecedented skeletons (1-3).

The Journal of Agricultural Education and Extension, 2006

... the geographic area they serve have better knowledge of the local agricultural systems and ..... more ... the geographic area they serve have better knowledge of the local agricultural systems and ... in their network, local authorities will increase these farmers' access to information and extension ... important to keep in mind the structure of the village communication networks (Hoang et ...

Fitoterapia, 2013

Three novel steroids (1-3), named cattienoids A-C together with schisanlactone A (4), were isolat... more Three novel steroids (1-3), named cattienoids A-C together with schisanlactone A (4), were isolated from fruiting bodies of Tomophagus cattienensis (Ganodermataceae)-a new mushroom recently collected from Cattien National Park, in Viet Nam. They possess an unusual seven membered lactone ring, derived from lanostane-type triterpenoids. Their structures were determined by spectroscopic methods. In addition, compounds 2 and 4 showed cytotoxicity against KB (a human epidermal carcinoma) cells with their IC 50 values of 91.2 and 63.3 μM, respectively. These compounds have neither antimicrobial activity nor inhibition of the tyrosinase.

There is increasing insight into how household poverty in rural and peri-urban areas is affected ... more There is increasing insight into how household poverty in rural and peri-urban areas is affected by developments in the markets for fruit, vegetables and flowers. This study extends the knowledge, and feeds into the debate on agricultural growth policies. Based on a positive outlook on the growth of horticultural production and distribution and marketing in the low income countries of Uganda and Vietnam, this paper asks whether poor and vulnerable groups in society share in the benefits of the foreseen economic expansion. Primary survey data is collected on the differentiated position of low-income households in different supply structures (with varying levels of vertical coordination) and markets (national, regional and international markets). The data support the following hypotheses: (i) For many resource-poor agents, horticulture-related activities make substantial contributions to their livelihood security certainly in the short term. (ii) Farming, trading services, small-scale...

Natural Product Communications, 2010

A new isoquinoline alkaloid, ampullosine (3-methyl-isoquinoline-6-carboxylic acid, 1), was isolat... more A new isoquinoline alkaloid, ampullosine (3-methyl-isoquinoline-6-carboxylic acid, 1), was isolated from Sepedonium ampullosporum and characterized by spectroscopic analysis and chemical reactions. This compound is responsible for the deep yellow color of the culture fluid of this species. Moreover, the known compounds sepedonin (2) and anhydrosepedonin (3) were detected. Twelve strains belonging to eight species of Sepedonium have been screened for these three metabolites by LC/ESI-SRM (selected reaction monitoring). Ampullosine (1) could be detected in almost all species in Sepedonium, but not in the phylogenetically more distant species S. brunneum and S. tulasneanum. Anhydrosepedonin (3) showed antifungal activity against the phytopathogenic fungus Cladosporium cucumerinum.

Natural Product Communications, 2014

Two new phenylbenzofuran-type stilbenoids named stemofurans X and Y (1, 2) were isolated from the... more Two new phenylbenzofuran-type stilbenoids named stemofurans X and Y (1, 2) were isolated from the roots of Stemona pierrei and S. tuberosa, respectively, together with ten known compounds. These compounds were stemanthrenes B-C (3, 4), (+)-syringaresinol (5), maistemonine (6), isomaistemonine (7) and sesamin (8) from S. pierrei, and stemophenanthrenes A-C (9–11) and isopinosylvin A (12) from S. tuberosa. Stemofurans X-Y (1, 2) showed moderate cytotoxicity against the four cancer cell lines KB (human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma), and Hep-G2 (hepatocellular carcinoma).

Natural Product Communications, 2007

Fruiting bodies collected in the field during the vegetation period in different developmental st... more Fruiting bodies collected in the field during the vegetation period in different developmental stages and mycelial cultures of 50 representatives of xylariaceous fungi were tested for antimicrobial and nematicidal activities, and 50 of their characteristic metabolites were studied for comparison. Furthermore, analytical HPLC profiling using diode array and electrospray mass spectrometric detection was performed to identify and quantify the major constituents, revealing that up to 10% of the dry fruiting body biomass may be composed of secondary metabolites. In several species, significant antimicrobial effects were noted upon incubation of the fruiting bodies in an agar diffusion assay, i.e., without any need for extraction and concentration of active constituents. These results suggest that most of the characteristic constituents of subfamily Hypoxyloideae (i.e. Hypoxylon and related genera) are involved in non-specific defense reactions that underwent specific permutations in the ...

International Journal of the Commons, 2009

Payments for environmental services in upper-catchments of Vietnam 65 agricultural households of ... more Payments for environmental services in upper-catchments of Vietnam 65 agricultural households of the upper-catchments in Northern Vietnam. We focus our attention on households identified as the poorest in the upper-catchment areas, i.e. those with a small endowment of productive land, limited access to water for irrigation, and low access to markets. We find that farmers are unlikely to participate in a voluntary land retirement program unless they are 'compensated' for the loss in food production and a 'forced' set aside program is likely to generate an overall negative impact on both poverty and environmental protection. Development and dissemination of improved technologies that increase food yields is a complementary strategy to promote environmental protection.

Phytochemistry, 2003

Three benzoyl p-terphenyl derivatives named thelephantins A, B and C were isolated from the ethyl... more Three benzoyl p-terphenyl derivatives named thelephantins A, B and C were isolated from the ethyl acetate extract of fruit bodies of the Thelephoraceous Basidiomycete Thelephora aurantiotincta. Their structures were elucidated by analysis of high-resolution 2D NMR, MS, IR and UV spectra.

The Chemical Record, 2006

In the course of our investigation on biologically active substances from inedible mushrooms in J... more In the course of our investigation on biologically active substances from inedible mushrooms in Japan, Germany, and Vietnam, we studied the chemical constituents of 22 species belonging to five families: Scutigeraceae, Polyporaceae, Xylariaceae, Thelephoraceae, and Paxillaceae. Various types of chemical substances were purified and characterized based on the modern spectroscopic methods and also on chemical reactions. These metabolites have shown a broad activity in many biological systems, such as antimicrobial, nematicidal, inhibition of NO production, antihuman immunodeficiency virus, tumor necrosis factor-α, and antioxidant activities. These isolated metabolites did not only show interesting activities, but also are employed as chemical markers supported for chemosystematics of these families. This review paper deals with the chemical constituents of 22 species, their biological activities, and also a discussion on chemosystematics.

Planta Medica, 2005

Four new azaphilones named multiformins A - D together with a known compound 4 : 5:4&... more Four new azaphilones named multiformins A - D together with a known compound 4 : 5:4':5'-tetrahydroxy-1 : 1'-binaphthyl were isolated from the methanolic stromatal extract of the xylariaceous ascomycete Hypoxylon multiforme. Their absolute structures were characterised by 2D-NMR, UV, IR, mass and CD spectroscopy. Multiformins A - D showed strong and apparently non-selective antimicrobial activity.

Phytochemistry, 2005

Investigation of the methanolic extract of the inedible mushroom Fomitopsis spraguei (Polyporacea... more Investigation of the methanolic extract of the inedible mushroom Fomitopsis spraguei (Polyporaceae) led to the isolation of five lanostane-type triterpenoids (1-5): three new compounds named fomitopsins A-C (2-4), and two known compounds, quercinic acid C (1) and 3alpha-carboxyacetyl-12beta-hydroxyquercinic acid (5). Their structures were determined by 2D NMR, MS, IR, UV spectra, and X-ray crystallographic analyses. An X-ray crystal structure analysis of quercinic acid C (1) established its stereochemistry as 3R,12R-dihydroxy-24R-methyl-23-oxo-25S-lanost-8-en-26-oic acid.

Phytochemistry, 2005

Other natural products U 0800 Cohaerins A and B, Azaphilones from the Fungus Hypoxylon cohaerens,... more Other natural products U 0800 Cohaerins A and B, Azaphilones from the Fungus Hypoxylon cohaerens, and Comparison of HPLC-Based Metabolite Profiles in Hypoxylon sect. Annulata.

Natural Product Research, 2013

The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Journal of Natural Products, 2002

Four compounds, daldinone A (1), daldinone B (2), daldiniapyrone (4-methoxy-5-carbomethoxy-6-pent... more Four compounds, daldinone A (1), daldinone B (2), daldiniapyrone (4-methoxy-5-carbomethoxy-6-pentyl-2H-pyran-2-one, 3), and daldinialanone (22R-hydroxylanosta-7,9(11),24-trien-3-one, 4), were isolated from an ethyl acetate extract of fruit bodies of Daldinia concentrica collected in Europe. In addition, 11 known compounds, 4:5:4′:5′-tetrahydroxy-1:1′-binaphthyl (5), 3,4,5-trihydroxy-1-tetralone (6), (+)-orthosporin (7), curuilignan D (8), (22E)-cholesta-4,6,8(14),22-tetraen-3-one (9), 3 ,22-dihydroxylanosta-7,9(11),24-triene (10), concentricol (11), concentricol B (12), concentricol C (13), concentricol D (14), and phenochalasin B (15), were obtained. The structures of the new compounds were elucidated by 2D NMR, MS, IR, and UV spectra and by X-ray crystallographic analysis. The absolute configurations of 1 and 4 were determined by CD spectroscopy and the modified Mosher's method, respectively. The chemotaxonomic relevance of the compounds obtained in this investigation is discussed.

Journal of Natural Products, 2003

A large amount of sex pheromones of the European spider Linyphia triangularis, 3R-hydroxybutyric ... more A large amount of sex pheromones of the European spider Linyphia triangularis, 3R-hydroxybutyric acid (1), its dimer 3R-(3R-hydroxybutyryloxy)butyric acid (2), and trimer 3R-[3R-(3R-hydroxybutyryloxy)butyryloxy]butyric acid (3) were isolated from the EtOAc extract of the Japanese inedible mushroom Hypoxylon truncatum. Anderson 1 isolated 3,4-dihydro-8-hydroxy-3-methylisocoumarin from the inedible mushroom Hypoxylon truncatum. Later Uebler 2 and Kern 3 also reported the same compound as a trail pheromone component of the ants Camponotus silvicola, C. rufipes, and Lasius fuliginosus, respectively. These results opened the avenue for research on compounds occurring in both insects and mushrooms. Recently, we investigated the chemical constituents of the Japanese H. truncatum and isolated a novel perylenequinone, truncatone. 4 Further fractionation of the ethyl acetate extract has now resulted in the isolation of monomeric 3R-hydroxybutyric acid (1), its dimer 3R-(3Rhydroxybutyryloxy)butyric acid (2), and trimer 3R-[3R-(3Rhydroxybutyryloxy)butyryloxy]butyric acid (3), which are known to be sex pheromones of the spider Linyphia triangularis (Clerck) and related species. 5 The EtOAc extract of H. truncatum was subjected to SiO 2 and Sephadex LH-20 column chromatography to give 3-hydroxybutyric acid (1) and a mixture of compounds 2 and 3. On the basis of the IR spectral evidence to support the presence of a carboxylic acid group (2400-3600 cm-1), samples of compound 1 and the mixture of 2 and 3 were methylated, then purified using preparative HPLC to give compounds 4, 5, and 6 as methylated derivatives of 1, 2, and 3, respectively. On the basis of analyses of IR, 1 H and 13 C NMR, and MS spectra and comparisons of the spectral data with those of authentic samples and reported spectral data, 6,7 their stuctures were determined to be 3-hydroxybutyric acid methyl ester (4), the dimer 3-(3-hydroxybutyryloxy)butyric acid methyl ester (5), and the trimer 3-[3-(3-hydroxybutyryloxy)butyryloxy]butyric acid methyl ester (6). To determine the absolute configurations of compounds 1, 2, and 3, they were each converted to 3-acetoxybutyric acid methyl ester (7), which was analyzed by GC-MS on a chiral column. Compound 1 was methylated with trimethylsilyldiazomethane and acetylated to afford compound 7. A mixture of dimer 5 and trimer 6 was saponified with potassium hydroxide in methanol, followed by methylation and acetylation to yield 7. Compound 7 was analyzed by gas chromatography-mass spectroscopy (GC-MS) on a chiral column with authentic samples (each 3R-and 3Sacetoxybutyric acid methyl ester, which was derived from 3R-and 3S-hydroxybutyric acid, respectively) to give the chromatograms shown in Figure 2. Consequently, the configurations of all asymmetric carbons of 1, 2, and 3 were established to be R.

Journal of Natural Products, 2004

Fractionation of the methanol extract of the fruit bodies of the xylariaceus ascomycete Hypoxylon... more Fractionation of the methanol extract of the fruit bodies of the xylariaceus ascomycete Hypoxylon rubiginosum resulted in the isolation of three new azaphilone derivatives named rubiginosins A-C (1-3) and a new fatty acid named rubiginosic acid (4), together with three known compounds, entonaemin A (5), daldinin C (6), and orsellinic acid. Their structures were elucidated by 2D NMR, MS, IR, and UV spectra and chemical reaction. The absolute configuration of compound 3 was established by CD spectroscopy. The structure of 4 was confirmed by X-ray crystallographic analysis.

Journal of Natural Products

Journal of Natural Products, 2006

Carneic acids A and B (1, 2) are polyketide antibiotics structurally related to phomopsidin. They... more Carneic acids A and B (1, 2) are polyketide antibiotics structurally related to phomopsidin. They were isolated as major constituents of the stromata of Hypoxylon carneum, a species that had shown a highly specific secondary metabolite profile in a survey of xylariaceous ascomycetes based on HPLC profiling. Their chemical structures were elucidated by a combination of spectroscopic methods and by preparation of derivatives. An X-ray crystal structure of the dinitrobenzoate of carneic acid B methyl ester (8) was obtained, even allowing for determination of its absolute structure. The carneic acids showed weak antibacterial and moderate antifungal activities in the serial dilution assay against selected microbial organisms. They appear to be species-specific marker molecules in H. carneum from different geographic regions, but do not constitute major metabolites of more than 100 species of Xylariaceae. Their biological and chemotaxonomic significance is discussed. Hypoxylon carneum Petch (Xylariaceae, Figure 1) is a woodinhabiting ascomycete, first described from Sri Lanka 1 and later also reported from the United States, Venezuela, New Zealand, 2 and France. 3 It is one of the few species in the large genus Hypoxylon that is not restricted to certain geographic areas, but was proven to have a truly cosmopolitan distribution, being present in temperate as well as in subtropical and tropical climates. As judged from our field studies on its occurrence in southwestern France, 3 it is apparently not rare. Because of its morphological similarity to the common H. rubiginosum and other related species, it has probably been frequently overlooked. 3 The most striking feature to discriminate H. carneum from its relatives can be readily determined without any need for detailed microscopic studies: its pigments in KOH are faint purple, while those of related species yield dense orange, brown, or yellowish pigments in KOH. 3 Also, H. carneum has faintly yellowish granules beneath the stromata surface, whereas those of its allies are orange, red, or brown. These features are due to the presence of different secondary metabolites, which was established by a HPLC profiling study of about 2500 specimens and cultures of Hypoxylon and related Xylariaceae. 3-6 Recent evidence for the molecular taxonomy of Hypoxylon and allies 7 revealed that the closest affinities of H. carneum (i.e., the clades H1 and H2 as described in ref 7), as inferred from a molecular phylogenetic study, are with species that preferably contain azaphilones. These clades comprise, aside from some taxa that were not yet studied for HPLC profiles, for example, H. cercidicola, H. petriniae, 3 H. perforatum, H. pilgerianum, and H. rubiginosum. 3,4 H. carneum strongly differed from all of these species in its HPLC profile. The common stromatal azaphilone pigments of many Hypoxylon spp. of clades H1 and H2 as described in ref 7 (i.e., mitorubrins, rubiginosins, and hypomiltin 3,4) were not detected by HPLC-MS, and instead 4:5:4′:5′-tetrahydroxy-1:1′binaphthyl (BNT, 3) and a series of apparently species-specific but yet unknown metabolites were detected as major components. 4 Interestingly, only BNT (3) and daldinins, but no mitorubrin-type azaphilones, were also reported previously from the core species of another side branch of clade H1, i.e., H. fuscum.

Journal of Natural Products, 2008

Three novel alkaloids (1-3), named pyriferines A-C, were isolated from fruiting bodies of Pseudob... more Three novel alkaloids (1-3), named pyriferines A-C, were isolated from fruiting bodies of Pseudobaeospora pyrifera. They possess an unusual eight-membered N/O-acetal ring, derived from L-glutamic acid, that is connected to an enolized 1,3-diketo moiety. The structures were determined by spectroscopic methods, and the absolute configuration of the glutamic acid moiety was established using GC-MS after Mosher-type derivatization. The fungal genus Pseudobaeospora (Tricholomataceae) is very rare and only described for Europe and North America. Thirteen species are known, but their chemical constituents are unknown. 1 The genus was first established by Singer 2,3 and recently generically circumscribed by Bas. 1,4 The species Pseudobaeospora pyrifera Bas & L. Krieglst. (Agaricales) investigated herein was described in 1998. 5 P. pyrifera is characterized by a 0.5-2.5 cm wide cap and a 1-3.5 cm long and 0.3-0.5 cm broad stipe. Cap and stem are pruinose sordid pink to pruinose vinaceous; the lamellae are rather dark reddish to violaceous pink colored. This little species grows on the ground in more or less moist areas (Pruno-Fraxinetum woods with Alnus, Prunus padus, Fraxinus). P. pyrifera is characterized by a greenish-blue to brownish-green reaction of the pileipellis with KOH solution. In this work, we describe the isolation and structural characterization of three novel unusual alkaloids that possess unprecedented skeletons (1-3).

The Journal of Agricultural Education and Extension, 2006

... the geographic area they serve have better knowledge of the local agricultural systems and ..... more ... the geographic area they serve have better knowledge of the local agricultural systems and ... in their network, local authorities will increase these farmers' access to information and extension ... important to keep in mind the structure of the village communication networks (Hoang et ...

Fitoterapia, 2013

Three novel steroids (1-3), named cattienoids A-C together with schisanlactone A (4), were isolat... more Three novel steroids (1-3), named cattienoids A-C together with schisanlactone A (4), were isolated from fruiting bodies of Tomophagus cattienensis (Ganodermataceae)-a new mushroom recently collected from Cattien National Park, in Viet Nam. They possess an unusual seven membered lactone ring, derived from lanostane-type triterpenoids. Their structures were determined by spectroscopic methods. In addition, compounds 2 and 4 showed cytotoxicity against KB (a human epidermal carcinoma) cells with their IC 50 values of 91.2 and 63.3 μM, respectively. These compounds have neither antimicrobial activity nor inhibition of the tyrosinase.