Bharat Bashyal - Academia.edu (original) (raw)
Papers by Bharat Bashyal
Journal of Natural Products, 2017
Natural Product Communications, 2007
A liquid fermentation culture of Fusarium acuminatum, endophytic in the root of Larrea tritentata... more A liquid fermentation culture of Fusarium acuminatum, endophytic in the root of Larrea tritentata, afforded a new furanopyrrolidone, 13α–hydroxylucilactaene (1), together with four known metabolites, NG–391 (2), NG–393 (3), enniatin A (4), and enniatin B (5). The structure and relative stereochemistry of 1 was established by extensive NMR spectral analysis and the known compounds 2 – 5 were identified by comparison of their spectroscopic data with those reported in the literature. The cytotoxicity of all compounds was evaluated in a panel of five human cancer cell lines [NCI–H460 (non-small cell lung), MCF–7 (breast), SF–268 (CNS glioma), MIA Pa Ca–2 (pancreatic carcinoma), PC-3M (metastatic prostate cancer)] and normal human fibroblast (WI–38) cells, and only enniatins A (4) and B (5) were shown to have significant cytotoxic activity.
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1988
PLOS Neglected Tropical Diseases, 2017
Journal of Natural Products
![Research paper thumbnail of Synthesis of the α-Mannosidase inhibitors swainsonine [(1S, 2R, 8R, 8aR)-1,2,8-trihydroxyoctahydroindolizine] and 1,4-dideoxy-1,4-imino-d-mannitol from mannose](https://attachments.academia-assets.com/67168164/thumbnails/1.jpg)
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Tetrahedron Letters, 1986
![Research paper thumbnail of Synthesis of 2s, 4s, 5s -dihydroxypipecolic acid and bulgecinine [2s,4s,5r-4-hydroxy-5- (hydroxymethyl)proline] from d-glucuronolactone, a strategy for the synthesis of 2s,4s-4-hydroxy-α-amino acids](https://attachments.academia-assets.com/46709277/thumbnails/1.jpg)
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Org. Biomol. Chem., 2016
The ATPase p97 is a ubiquitin targeted segregase that uses the energy of ATP binding and hydrolys... more The ATPase p97 is a ubiquitin targeted segregase that uses the energy of ATP binding and hydrolysis to extract ubiquitylated substrates from biological membranes, from other proteins, or from protein complexes to carry out myriad tasks in eukaryotes. Increased p97 activity has been linked to a poor prognosis in cancer patients, making p97 an anti-neoplastic target. In the present study, we show that dehydrocurvularin (DHC) and its chlorinated variants are covalent inhibitors of p97, interfering with its ATPase activity. Interestingly, cellular studies revealed both DHC and its monochloro analogue interfere with both the proteasome and p97, whereas its dichloro analogue showed p97 specificity.
Journal of Natural Products, 2006
... 10 Although δ-elemanolides from Zinnia species have not been evaluated for their biological a... more ... 10 Although δ-elemanolides from Zinnia species have not been evaluated for their biological activity, three γ-elemanolide dilactones, zinaflavins B, D, and F ... Emily L. Whitson, SMV Damayanthi Mala, Charles A. Veltri, Tim S. Bugni, E. Dilip de Silva, and Chris M. Ireland. Journal of ...
Journal of Natural Products, Oct 28, 2011
Natural product communications, 2015
Two new metabolites, 6-oxo-12-norcytochalasin D (1) and 4,5-di-isobutyl-2(1H)-pyrimidinone (2), t... more Two new metabolites, 6-oxo-12-norcytochalasin D (1) and 4,5-di-isobutyl-2(1H)-pyrimidinone (2), together with seven known metabolites, cytochalasins D (3), Q (4), and N (5), 12-hydroxyzygosporin G (6), heptelidic acid chlorohydrin (7), (+)-heptelidic acid (8), and trichoderonic acid A (9), were isolated from Xylariaceae sp. FL0390, a fungal endophyte inhabiting Spanish moss, Tillandsia usneoides. Metabolite 1 is the first example of a 12-norcytochalasin. All metabolites, except 2 and 9, showed cytotoxic activity in a panel of five human tumor cell lines with IC50S of 0.2-5.0 μM.
Seimatoantlerium nepalense, sp. nov. is described as a coelomycetous species. It was isolated as ... more Seimatoantlerium nepalense, sp. nov. is described as a coelomycetous species. It was isolated as an endophyte of Taxus wallachiana in the Kaski district of Western Nepal. The genus is characterized by the dehiscent apical appendage apparatus on its conidia, its unique method of acervular conidiogenesis, and its basal conidial appendage arising exogenously to a pedicel. This species primarily differs from the only other known fungus in this genus, S. tepuiense, by virtue of its smaller conidial size, structural differences in the apical conidial appendage apparatus, a unique pigment deposition in the sub-apical cells, its endophytic nature, and its plant host. Most notably, however, both species in this genus produce taxol in culture.
The open virology journal, 2013
Most antiretroviral drugs currently in use to treat an HIV-1 infection are chemically synthesized... more Most antiretroviral drugs currently in use to treat an HIV-1 infection are chemically synthesized and lead to the development of viral resistance, as well as cause severe toxicities. However, a largely unexplored source for HIV-1 drug discovery is endophytic fungi that live in a symbiotic relationship with plants. These fungi produce biologically active secondary metabolites, which are natural products that are beneficial to the host. We prepared several hundred extracts from endophytic fungi of desert plants and evaluated the inhibitory effects on HIV-1 replication of those extracts that showed less than 30% cytotoxicity in T-lymphocytes. Those extracts that inhibited viral replication were fractionated in order to isolate the compounds responsible for activity. Multiple rounds of fractionation and antiviral evaluation lead to the identification of four compounds, which almost completely impede HIV-1 replication. These studies demonstrate that metabolites from endophytic fungi of d...
Bioorganic & medicinal chemistry, 2014
Screening of a small library of natural product extracts derived from endophytic fungi of the Son... more Screening of a small library of natural product extracts derived from endophytic fungi of the Sonoran desert plants in a cell-based anti-HIV assay involving T-cells infected with the HIV-1 virus identified the EtOAc extract of a fermentation broth of Alternaria tenuissima QUE1Se inhabiting the stem tissue of Quercus emoryi as a promising candidate for further investigation. Bioactivity-guided fractionation of this extract led to the isolation and identification of two new metabolites, altertoxins V (1) and VI (2) together with the known compounds, altertoxins I (3), II (4), and III (5). The structures of 1 and 2 were determined by detailed spectroscopic analysis and those of 3-5 were established by comparison with reported data. When tested in our cell-based assay at concentrations insignificantly toxic to T-cells, altertoxins V (1), I (3), II (4), and III (5) completely inhibited replication of the HIV-1 virus at concentrations of 0.50, 2.20, 0.30, and 1.50 μM, respectively. Our fi...
Tetrahedron Letters, 1986
Natural Product Research, 2010
Two new rare irregular sesquiterpenes, tricinonoic acid (1) and tricindiol (2), and the known fur... more Two new rare irregular sesquiterpenes, tricinonoic acid (1) and tricindiol (2), and the known furanopyrrolidones, NG-391 (3) and NG-393 (4), have been isolated from an EtOAc extract of Fusarium tricinctum, a fungus endophytic in the root tissue of the Sonoran desert plant, Rumex hymenosepalus. The structures of 1 and 2 were elucidated on the basis of their high-resolution mass, 1D and 2D NMR spectroscopic data. A possible biosynthetic route to 1 and 2 from farnesyl diphosphate is proposed.
![Research paper thumbnail of Synthesis of 2s, 4s, 5s -dihydroxypipecolic acid and bulgecinine [2s,4s,5r-4-hydroxy-5- (hydroxymethyl)proline] from d-glucuronolactone, a strategy for the synthesis of 2s,4s-4-hydroxy-α-amino acids](https://attachments.academia-assets.com/46668017/thumbnails/1.jpg)
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Journal of Natural Products, 2017
Natural Product Communications, 2007
A liquid fermentation culture of Fusarium acuminatum, endophytic in the root of Larrea tritentata... more A liquid fermentation culture of Fusarium acuminatum, endophytic in the root of Larrea tritentata, afforded a new furanopyrrolidone, 13α–hydroxylucilactaene (1), together with four known metabolites, NG–391 (2), NG–393 (3), enniatin A (4), and enniatin B (5). The structure and relative stereochemistry of 1 was established by extensive NMR spectral analysis and the known compounds 2 – 5 were identified by comparison of their spectroscopic data with those reported in the literature. The cytotoxicity of all compounds was evaluated in a panel of five human cancer cell lines [NCI–H460 (non-small cell lung), MCF–7 (breast), SF–268 (CNS glioma), MIA Pa Ca–2 (pancreatic carcinoma), PC-3M (metastatic prostate cancer)] and normal human fibroblast (WI–38) cells, and only enniatins A (4) and B (5) were shown to have significant cytotoxic activity.
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1988
PLOS Neglected Tropical Diseases, 2017
Journal of Natural Products
Tetrahedron Letters, 1986
Org. Biomol. Chem., 2016
The ATPase p97 is a ubiquitin targeted segregase that uses the energy of ATP binding and hydrolys... more The ATPase p97 is a ubiquitin targeted segregase that uses the energy of ATP binding and hydrolysis to extract ubiquitylated substrates from biological membranes, from other proteins, or from protein complexes to carry out myriad tasks in eukaryotes. Increased p97 activity has been linked to a poor prognosis in cancer patients, making p97 an anti-neoplastic target. In the present study, we show that dehydrocurvularin (DHC) and its chlorinated variants are covalent inhibitors of p97, interfering with its ATPase activity. Interestingly, cellular studies revealed both DHC and its monochloro analogue interfere with both the proteasome and p97, whereas its dichloro analogue showed p97 specificity.
Journal of Natural Products, 2006
... 10 Although δ-elemanolides from Zinnia species have not been evaluated for their biological a... more ... 10 Although δ-elemanolides from Zinnia species have not been evaluated for their biological activity, three γ-elemanolide dilactones, zinaflavins B, D, and F ... Emily L. Whitson, SMV Damayanthi Mala, Charles A. Veltri, Tim S. Bugni, E. Dilip de Silva, and Chris M. Ireland. Journal of ...
Journal of Natural Products, Oct 28, 2011
Natural product communications, 2015
Two new metabolites, 6-oxo-12-norcytochalasin D (1) and 4,5-di-isobutyl-2(1H)-pyrimidinone (2), t... more Two new metabolites, 6-oxo-12-norcytochalasin D (1) and 4,5-di-isobutyl-2(1H)-pyrimidinone (2), together with seven known metabolites, cytochalasins D (3), Q (4), and N (5), 12-hydroxyzygosporin G (6), heptelidic acid chlorohydrin (7), (+)-heptelidic acid (8), and trichoderonic acid A (9), were isolated from Xylariaceae sp. FL0390, a fungal endophyte inhabiting Spanish moss, Tillandsia usneoides. Metabolite 1 is the first example of a 12-norcytochalasin. All metabolites, except 2 and 9, showed cytotoxic activity in a panel of five human tumor cell lines with IC50S of 0.2-5.0 μM.
Seimatoantlerium nepalense, sp. nov. is described as a coelomycetous species. It was isolated as ... more Seimatoantlerium nepalense, sp. nov. is described as a coelomycetous species. It was isolated as an endophyte of Taxus wallachiana in the Kaski district of Western Nepal. The genus is characterized by the dehiscent apical appendage apparatus on its conidia, its unique method of acervular conidiogenesis, and its basal conidial appendage arising exogenously to a pedicel. This species primarily differs from the only other known fungus in this genus, S. tepuiense, by virtue of its smaller conidial size, structural differences in the apical conidial appendage apparatus, a unique pigment deposition in the sub-apical cells, its endophytic nature, and its plant host. Most notably, however, both species in this genus produce taxol in culture.
The open virology journal, 2013
Most antiretroviral drugs currently in use to treat an HIV-1 infection are chemically synthesized... more Most antiretroviral drugs currently in use to treat an HIV-1 infection are chemically synthesized and lead to the development of viral resistance, as well as cause severe toxicities. However, a largely unexplored source for HIV-1 drug discovery is endophytic fungi that live in a symbiotic relationship with plants. These fungi produce biologically active secondary metabolites, which are natural products that are beneficial to the host. We prepared several hundred extracts from endophytic fungi of desert plants and evaluated the inhibitory effects on HIV-1 replication of those extracts that showed less than 30% cytotoxicity in T-lymphocytes. Those extracts that inhibited viral replication were fractionated in order to isolate the compounds responsible for activity. Multiple rounds of fractionation and antiviral evaluation lead to the identification of four compounds, which almost completely impede HIV-1 replication. These studies demonstrate that metabolites from endophytic fungi of d...
Bioorganic & medicinal chemistry, 2014
Screening of a small library of natural product extracts derived from endophytic fungi of the Son... more Screening of a small library of natural product extracts derived from endophytic fungi of the Sonoran desert plants in a cell-based anti-HIV assay involving T-cells infected with the HIV-1 virus identified the EtOAc extract of a fermentation broth of Alternaria tenuissima QUE1Se inhabiting the stem tissue of Quercus emoryi as a promising candidate for further investigation. Bioactivity-guided fractionation of this extract led to the isolation and identification of two new metabolites, altertoxins V (1) and VI (2) together with the known compounds, altertoxins I (3), II (4), and III (5). The structures of 1 and 2 were determined by detailed spectroscopic analysis and those of 3-5 were established by comparison with reported data. When tested in our cell-based assay at concentrations insignificantly toxic to T-cells, altertoxins V (1), I (3), II (4), and III (5) completely inhibited replication of the HIV-1 virus at concentrations of 0.50, 2.20, 0.30, and 1.50 μM, respectively. Our fi...
Tetrahedron Letters, 1986
Natural Product Research, 2010
Two new rare irregular sesquiterpenes, tricinonoic acid (1) and tricindiol (2), and the known fur... more Two new rare irregular sesquiterpenes, tricinonoic acid (1) and tricindiol (2), and the known furanopyrrolidones, NG-391 (3) and NG-393 (4), have been isolated from an EtOAc extract of Fusarium tricinctum, a fungus endophytic in the root tissue of the Sonoran desert plant, Rumex hymenosepalus. The structures of 1 and 2 were elucidated on the basis of their high-resolution mass, 1D and 2D NMR spectroscopic data. A possible biosynthetic route to 1 and 2 from farnesyl diphosphate is proposed.