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Yonghui Zhang - One of the best experts on this subject based on the ideXlab platform.
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new α pyrone derivatives with herbicidal activity from the endophytic fungus Alternaria brassicicola
Bioorganic Chemistry, 2021Co-Authors: Zhangyan Huang, Weiguang Sun, Sitian Zhang, Jianping Wang, Weixi Gao, Xia Chen, Fei Cao, Yonghui ZhangAbstract:Abstract Three pairs of undescribed enantiomeric α-pyrone derivatives (1a/1b–3a/3b) and six undescribed congeners (4–9), were obtained from the fungus Alternaria brassicicola that was isolated from the fresh leaves of Siegesbeckia pubescens Makino (Compositae). The structures of these new compounds were characterized by extensive NMR spectroscopic and HRESIMS data, and their absolute configurations were further elucidated by a modified Mosher's method, chemical conversion, single-crystal X-ray diffraction analysis, and ECD calculations. This is the first report of three pairs of enantiomeric α-pyrone derivatives from the fungus A. brassicicola, and these enantiomers were successfully acquired from scalemic mixtures via chiral HPLC. Compounds 1a/1b–3a/3b and 4–9 were evaluated for the herbicidal activity against Echinochloa crusgalli, Setaria viridis, Portulaca oleracea, and Taraxacum mongolicum. At a concentration of 100 μg/mL, compounds 1a and 1b could significantly inhibit the germination of monocotyledon weed seeds (E. crusgalli and S. viridis) with inhibitory ratios ranging from 68.6 ± 6.4% to 84.2 ± 5.1%, which was equivalent to that of the positive control (glyphosate). The potential structure-herbicidal activity relationship of these compounds was also discussed. To a certain extent, the results of this study will attract great interest for the potential practical application of promising fungal metabolites, α-pyrone derivatives, as ecofriendly herbicides.
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fusicoccane derived diterpenoids with bridgehead double bond containing tricyclo 9 2 1 03 7 tetradecane ring systems from Alternaria brassicicola
Bioorganic Chemistry, 2020Co-Authors: Lifen Pan, Sitian Zhang, Shuang Lin, Jianping Wang, Beiye Yang, Junjun Liu, Yonghui ZhangAbstract:Abstract Fusicoccane-derived diterpenoids bearing a unique bridgehead double-bond-containing tricyclo[9.2.1.03,7]tetradecane (5-9-5 ring system) core skeleton represent a rarely reported class of rearranged terpenoids, which traced back to fusicoccanes with a classical dicyclopenta[a,d]cyclooctane (5-8-5 ring system) core skeleton via a crucial Wagner-Meerwein rearrangement reaction. In this research, alterbrassicenes B–D (1–3), three new rearranged fusicoccane diterpenoids bearing a rare bridgehead double-bond-containing tricyclo[9.2.1.03,7]tetradecane core skeleton, together with two known congeners, brassicicenes O and K (4 and 5), were isolated from the modified cultures of fungus Alternaria brassicicola. Their structures were elucidated by comprehensive analyses of the NMR and HRESIMS data, and the absolute configurations of 1 and 4 were further confirmed via a combination of 13C NMR and ECD calculations and single-crystal X-ray diffraction analysis (Cu Kα). Interestingly, alterbrassicene B (1) represented the second case of bridgehead C-10–C-11 double-bond-containing natural products with a bicyclo[6.2.1]undecane core skeleton, and also featured an undescribed oxygen bridge between C-6 and C-14 to construct an unprecedentedly caged tetracyclic system. Alterbrassicenes B–D showed moderate cytotoxic activity against certain human tumor cell lines with IC50 values in the range of 15.87–36.85 μM.
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modified fusicoccane type diterpenoids from Alternaria brassicicola
Journal of Natural Products, 2020Co-Authors: Shuang Lin, Sitian Zhang, Jianping Wang, Lifen Pan, Chenwei Chai, Beiye Yang, Junjun Liu, Yonghui ZhangAbstract:Seven new modified fusicoccane-type diterpenoids (1-7), together with two known congeners (8 and 9), were obtained from Alternaria brassicicola. Their structures were elucidated from a combination of NMR and HRESIMS data and 13C NMR calculation as well as DP4+ probability analyses, and the absolute configurations of 1-5 were determined by ECD calculation and single-crystal X-ray diffraction (Cu Kα). Compounds 1-3 belong to a rare class of 16-nor-dicyclopenta[a,d]cyclooctane diterpenoids, and compounds 2 and 4 represent the first examples of fusicoccane-type diterpenoids featuring two previously undescribed tetracyclic 5/6/6/5 ring systems, while compound 5 features a previously undescribed tetracyclic 5/8/5/3 ring system. Compound 7 was moderately anti-inflammatory, and compounds 2, 3, 5, and 7 were weakly cytotoxic.
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new cytotoxic tricycloalternarenes from fungus Alternaria brassicicola
Bioorganic Chemistry, 2019Co-Authors: Ying Tang, Weiguang Sun, Jiankun Guan, Sitian Zhang, Shuang Lin, Jianping Wang, Yonghui ZhangAbstract:Abstract Seven previously undescribed metabolites, designated as tricycloalternarenes Q–W (1–7), were isolated and identified from the fermented rice substrate of fungus Alternaria brassicicola. The planar and absolute structures of all new compounds were determined on the basis of extensive NMR spectroscopic data, a modified Mosher’s method, X-ray crystallographic analysis, and electronic circular dichroism (ECD) spectral analyses. All the isolates were evaluated for in vitro cytotoxicity against five human tumor MM231, MM468, HeLa, SW1990, and SW480 cell lines, and compounds 1, 2, 5, and 7 showed selective cytotoxicity against certain human tumor cell lines with IC50 values ranging from 12.83 to 32.87 μM, with no obvious cytotoxicity to the normal LO2 cell.
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alterbrassinoids a d fusicoccane derived diterpenoid dimers featuring different carbon skeletons from Alternaria brassicicola
Organic Letters, 2019Co-Authors: Shuang Lin, Sitian Zhang, Jianping Wang, Beiye Yang, Junjun Liu, Xincai Hao, Yonghui ZhangAbstract:Alterbrassinoids A–D (1–4), the first examples of fusicoccane-derived diterpenoid dimers furnished by forming an undescribed C-12–C-18′ linkage, were isolated from modified cultures of Alternaria brassicicola. Compounds 1 and 2 represent unprecedented heterodimers, whereas 3 and 4 represent unprecedented homodimers, and 4 also features an undescribed anhydride motif. Their structures were assigned via spectroscopic methods, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Putative biosynthetic pathways and a bioactivity evaluation for 1–4 were discussed.
Jianping Wang - One of the best experts on this subject based on the ideXlab platform.
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new α pyrone derivatives with herbicidal activity from the endophytic fungus Alternaria brassicicola
Bioorganic Chemistry, 2021Co-Authors: Zhangyan Huang, Weiguang Sun, Sitian Zhang, Jianping Wang, Weixi Gao, Xia Chen, Fei Cao, Yonghui ZhangAbstract:Abstract Three pairs of undescribed enantiomeric α-pyrone derivatives (1a/1b–3a/3b) and six undescribed congeners (4–9), were obtained from the fungus Alternaria brassicicola that was isolated from the fresh leaves of Siegesbeckia pubescens Makino (Compositae). The structures of these new compounds were characterized by extensive NMR spectroscopic and HRESIMS data, and their absolute configurations were further elucidated by a modified Mosher's method, chemical conversion, single-crystal X-ray diffraction analysis, and ECD calculations. This is the first report of three pairs of enantiomeric α-pyrone derivatives from the fungus A. brassicicola, and these enantiomers were successfully acquired from scalemic mixtures via chiral HPLC. Compounds 1a/1b–3a/3b and 4–9 were evaluated for the herbicidal activity against Echinochloa crusgalli, Setaria viridis, Portulaca oleracea, and Taraxacum mongolicum. At a concentration of 100 μg/mL, compounds 1a and 1b could significantly inhibit the germination of monocotyledon weed seeds (E. crusgalli and S. viridis) with inhibitory ratios ranging from 68.6 ± 6.4% to 84.2 ± 5.1%, which was equivalent to that of the positive control (glyphosate). The potential structure-herbicidal activity relationship of these compounds was also discussed. To a certain extent, the results of this study will attract great interest for the potential practical application of promising fungal metabolites, α-pyrone derivatives, as ecofriendly herbicides.
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fusicoccane derived diterpenoids with bridgehead double bond containing tricyclo 9 2 1 03 7 tetradecane ring systems from Alternaria brassicicola
Bioorganic Chemistry, 2020Co-Authors: Lifen Pan, Sitian Zhang, Shuang Lin, Jianping Wang, Beiye Yang, Junjun Liu, Yonghui ZhangAbstract:Abstract Fusicoccane-derived diterpenoids bearing a unique bridgehead double-bond-containing tricyclo[9.2.1.03,7]tetradecane (5-9-5 ring system) core skeleton represent a rarely reported class of rearranged terpenoids, which traced back to fusicoccanes with a classical dicyclopenta[a,d]cyclooctane (5-8-5 ring system) core skeleton via a crucial Wagner-Meerwein rearrangement reaction. In this research, alterbrassicenes B–D (1–3), three new rearranged fusicoccane diterpenoids bearing a rare bridgehead double-bond-containing tricyclo[9.2.1.03,7]tetradecane core skeleton, together with two known congeners, brassicicenes O and K (4 and 5), were isolated from the modified cultures of fungus Alternaria brassicicola. Their structures were elucidated by comprehensive analyses of the NMR and HRESIMS data, and the absolute configurations of 1 and 4 were further confirmed via a combination of 13C NMR and ECD calculations and single-crystal X-ray diffraction analysis (Cu Kα). Interestingly, alterbrassicene B (1) represented the second case of bridgehead C-10–C-11 double-bond-containing natural products with a bicyclo[6.2.1]undecane core skeleton, and also featured an undescribed oxygen bridge between C-6 and C-14 to construct an unprecedentedly caged tetracyclic system. Alterbrassicenes B–D showed moderate cytotoxic activity against certain human tumor cell lines with IC50 values in the range of 15.87–36.85 μM.
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modified fusicoccane type diterpenoids from Alternaria brassicicola
Journal of Natural Products, 2020Co-Authors: Shuang Lin, Sitian Zhang, Jianping Wang, Lifen Pan, Chenwei Chai, Beiye Yang, Junjun Liu, Yonghui ZhangAbstract:Seven new modified fusicoccane-type diterpenoids (1-7), together with two known congeners (8 and 9), were obtained from Alternaria brassicicola. Their structures were elucidated from a combination of NMR and HRESIMS data and 13C NMR calculation as well as DP4+ probability analyses, and the absolute configurations of 1-5 were determined by ECD calculation and single-crystal X-ray diffraction (Cu Kα). Compounds 1-3 belong to a rare class of 16-nor-dicyclopenta[a,d]cyclooctane diterpenoids, and compounds 2 and 4 represent the first examples of fusicoccane-type diterpenoids featuring two previously undescribed tetracyclic 5/6/6/5 ring systems, while compound 5 features a previously undescribed tetracyclic 5/8/5/3 ring system. Compound 7 was moderately anti-inflammatory, and compounds 2, 3, 5, and 7 were weakly cytotoxic.
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new cytotoxic tricycloalternarenes from fungus Alternaria brassicicola
Bioorganic Chemistry, 2019Co-Authors: Ying Tang, Weiguang Sun, Jiankun Guan, Sitian Zhang, Shuang Lin, Jianping Wang, Yonghui ZhangAbstract:Abstract Seven previously undescribed metabolites, designated as tricycloalternarenes Q–W (1–7), were isolated and identified from the fermented rice substrate of fungus Alternaria brassicicola. The planar and absolute structures of all new compounds were determined on the basis of extensive NMR spectroscopic data, a modified Mosher’s method, X-ray crystallographic analysis, and electronic circular dichroism (ECD) spectral analyses. All the isolates were evaluated for in vitro cytotoxicity against five human tumor MM231, MM468, HeLa, SW1990, and SW480 cell lines, and compounds 1, 2, 5, and 7 showed selective cytotoxicity against certain human tumor cell lines with IC50 values ranging from 12.83 to 32.87 μM, with no obvious cytotoxicity to the normal LO2 cell.
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alterbrassinoids a d fusicoccane derived diterpenoid dimers featuring different carbon skeletons from Alternaria brassicicola
Organic Letters, 2019Co-Authors: Shuang Lin, Sitian Zhang, Jianping Wang, Beiye Yang, Junjun Liu, Xincai Hao, Yonghui ZhangAbstract:Alterbrassinoids A–D (1–4), the first examples of fusicoccane-derived diterpenoid dimers furnished by forming an undescribed C-12–C-18′ linkage, were isolated from modified cultures of Alternaria brassicicola. Compounds 1 and 2 represent unprecedented heterodimers, whereas 3 and 4 represent unprecedented homodimers, and 4 also features an undescribed anhydride motif. Their structures were assigned via spectroscopic methods, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Putative biosynthetic pathways and a bioactivity evaluation for 1–4 were discussed.
Philippe Simoneau - One of the best experts on this subject based on the ideXlab platform.
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Genome sequence of the necrotrophic plant pathogen Alternaria brassicicola Abra43
Genome Announcements, 2018Co-Authors: Elodie Belmas, Philippe Simoneau, Claire Campion, Martial Briand, Anthony Kwasiborski, Justine Colou, Guillaume Nguyen, B. Iacomi, Philippe Grappin, Matthieu BarretAbstract:Alternaria brassicicola causes dark spot (or black spot) disease, which is one of the most common and destructive fungal diseases of Brassicaceae spp. worldwide. Here, we report the draft genome sequence of strain Abra43. The assembly comprises 29 scaffolds, with an N50 value of 2.1 Mb. The assembled genome was 31,036,461 bp in length, with a G+C content of 50.85%.
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Characterization of glutathione transferases involved in the pathogenicity of Alternaria brassicicola
BMC Microbiology, 2015Co-Authors: Benoit Calmes, Thomas Guillemette, Nelly Bataillé, Melanie Morel, Eric Gelhaye, Philippe SimoneauAbstract:Background: Glutathione transferases (GSTs) represent an extended family of multifunctional proteins involved in detoxification processes and tolerance to oxidative stress. We thus anticipated that some GSTs could play an essential role in the protection of fungal necrotrophs against plant-derived toxic metabolites and reactive oxygen species that accumulate at the host-pathogen interface during infection. Results: Mining the genome of the necrotrophic Brassica pathogen Alternaria brassicicola for glutathione transferase revealed 23 sequences, 17 of which could be clustered into the main classes previously defined for fungal GSTs and six were 'orphans'. Five isothiocyanate-inducible GSTs from five different classes were more thoroughly investigated. Analysis of their catalytic properties revealed that two GSTs, belonging to the GSTFuA and GTT1 classes, exhibited GSH transferase activity with isothiocyanates (ITC) and peroxidase activity with cumene hydroperoxide, respectively. Mutant deficient for these two GSTs were however neither more susceptible to ITC nor less aggressive than the wild-type parental strain. By contrast mutants deficient for two other GSTs, belonging to the Ure2pB and GSTO classes, were distinguished by their hyper-susceptibility to ITC and low aggressiveness against Brassica oleracea. In particular AbGSTO1 could participate in cell tolerance to ITC due to its glutathione-dependent thioltransferase activity. The fifth ITC-inducible GST belonged to the MAPEG class and although it was not possible to produce the soluble active form of this protein in a bacterial expression system, the corresponding deficient mutant failed to develop normal symptoms on host plant tissues. Conclusions: Among the five ITC-inducible GSTs analyzed in this study, three were found essential for full aggressiveness of A. brassicicola on host plant. This, to our knowledge is the first evidence that GSTs might be essential virulence factors for fungal necrotrophs.
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Phosphoproteome profiles of the phytopathogenic fungi [i]Alternaria brassicicola[/i] and [i]Botrytis cinerea[/i] during exponential growth in axenic cultures
Proteomics, 2014Co-Authors: Marlène Davanture, Philippe Simoneau, Claire Campion, Nelly Bataillé, Jerome Dumur, Benoit Valot, Michel Zivy, Sabine, Helma Fillinger-davidAbstract:This study describes the gel-free phosphoproteomic analysis of the phytopathogenic fungi Alternaria brassicicola and Botrytis cinerea grown in vitro under nonlimiting conditions. Using a combination of strong cation exchange and IMAC prior to LC-MS, we identified over 1350 phosphopeptides per fungus representing over 800 phosphoproteins. The preferred phosphorylation sites were found on serine (>80%) and threonine (>15%), whereas phosphorylated tyrosine residues were found at less than 1% in A. brassicicola and at a slightly higher ratio in B. cinerea (1.5%). Biological processes represented principally among the phoshoproteins were those involved in response and transduction of stimuli as well as in regulation of cellular and metabolic processes. Most known elements of signal transduction were found in the datasets of both fungi. This study also revealed unexpected phosphorylation sites in histidine kinases, a category overrepresented in filamentous ascomycetes compared to yeast. The data have been deposited to the ProteomeXchange database with identifier PXD000817 (http://proteomecentral.proteomexchange.org/dataset/PXD000817).
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dehydrin like proteins in the necrotrophic fungus Alternaria brassicicola have a role in plant pathogenesis and stress response
PLOS ONE, 2013Co-Authors: Stéphanie Pochon, Philippe Simoneau, Sandrine Pigné, Samuel BalidasAbstract:In this study, the roles of fungal dehydrin-like proteins in pathogenicity and protection against environmental stresses were investigated in the necrotrophic seed-borne fungus Alternaria brassicicola. Three proteins (called AbDhn1, AbDhn2 and AbDhn3), harbouring the asparagine-proline-arginine (DPR) signature pattern and sharing the characteristic features of fungal dehydrin-like proteins, were identified in the A. brassicicola genome. The expression of these genes was induced in response to various stresses and found to be regulated by the AbHog1 mitogen-activated protein kinase (MAPK) pathway. A knock-out approach showed that dehydrin-like proteins have an impact mainly on oxidative stress tolerance and on conidial survival upon exposure to high and freezing temperatures. The subcellular localization revealed that AbDhn1 and AbDhn2 were associated with peroxisomes, which is consistent with a possible perturbation of protective mechanisms to counteract oxidative stress and maintain the redox balance in AbDhn mutants. Finally, we show that the double deletion mutant ΔΔabdhn1-abdhn2 was highly compromised in its pathogenicity. By comparison to the wild-type, this mutant exhibited lower aggressiveness on B. oleracea leaves and a reduced capacity to be transmitted to Arabidopsis seeds via siliques. The double mutant was also affected with respect to conidiation, another crucial step in the epidemiology of the disease.
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The Arabidopsis thaliana-Alternaria brassicicola pathosystem: A model interaction for investigating seed transmission of necrotrophic fungi
Plant methods, 2012Co-Authors: Stéphanie Pochon, Emmanuel Terrasson, Thomas Guillemette, Beatrice Iacomi-vasilescu, Sonia Georgeault, Marjorie Juchaux, Romain Berruyer, Isabelle Debeaujon, Philippe Simoneau, Claire CampionAbstract:Background: Seed transmission constitutes a major component of the parasitic cycle for several fungal pathogens. However, very little is known concerning fungal or plant genetic factors that impact seed transmission and mechanisms underlying this key biological trait have yet to be clarified. Such lack of available data could be probably explained by the absence of suitable model pathosystem to study plant-fungus interactions during the plant reproductive phase. Results: Here we report on setting up a new pathosystem that could facilitate the study of fungal seed transmission. Reproductive organs of Arabidopsis thaliana were inoculated with Alternaria brassicicola conidia. Parameters (floral vs fruit route, seed collection date, plant and silique developmental stages) that could influence the seed transmission efficiency were tested to define optimal seed infection conditions. Microscopic observations revealed that the fungus penetrates siliques through cellular junctions, replum and stomata, and into seed coats either directly or through cracks. The ability of the osmosensitive fungal mutant nik1Δ3 to transmit to A. thaliana seeds was analyzed. A significant decrease in seed transmission rate was observed compared to the wild-type parental strain, confirming that a functional osmoregulation pathway is required for efficient seed transmission of the fungus. Similarly, to test the role of flavonoids in seed coat protection against pathogens, a transparent testa Arabidopsis mutant (tt4-1 )n ot producing any flavonoid was used as host plant. Unexpectedly, tt4-1 seeds were infected to a significantly lower extent than wild-type seeds, possibly due to over-accumulation of other antimicrobial metabolites. Conclusions: The Arabidopsis thaliana-Alternaria brassicicola pathosystem, that have been widely used to study plant-pathogen interactions during the vegetative phase, also proved to constitute a suitable model pathosystem for detailed analysis of plant-pathogen interactions during the reproductive phase. We demonstrated that it provides an excellent system for investigating the impact of different fungal or plant mutations on the seed transmission process and therefore paves the way towards future high-throughput screening of both Arabidopsis and fungal mutant.
Weiguang Sun - One of the best experts on this subject based on the ideXlab platform.
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new α pyrone derivatives with herbicidal activity from the endophytic fungus Alternaria brassicicola
Bioorganic Chemistry, 2021Co-Authors: Zhangyan Huang, Weiguang Sun, Sitian Zhang, Jianping Wang, Weixi Gao, Xia Chen, Fei Cao, Yonghui ZhangAbstract:Abstract Three pairs of undescribed enantiomeric α-pyrone derivatives (1a/1b–3a/3b) and six undescribed congeners (4–9), were obtained from the fungus Alternaria brassicicola that was isolated from the fresh leaves of Siegesbeckia pubescens Makino (Compositae). The structures of these new compounds were characterized by extensive NMR spectroscopic and HRESIMS data, and their absolute configurations were further elucidated by a modified Mosher's method, chemical conversion, single-crystal X-ray diffraction analysis, and ECD calculations. This is the first report of three pairs of enantiomeric α-pyrone derivatives from the fungus A. brassicicola, and these enantiomers were successfully acquired from scalemic mixtures via chiral HPLC. Compounds 1a/1b–3a/3b and 4–9 were evaluated for the herbicidal activity against Echinochloa crusgalli, Setaria viridis, Portulaca oleracea, and Taraxacum mongolicum. At a concentration of 100 μg/mL, compounds 1a and 1b could significantly inhibit the germination of monocotyledon weed seeds (E. crusgalli and S. viridis) with inhibitory ratios ranging from 68.6 ± 6.4% to 84.2 ± 5.1%, which was equivalent to that of the positive control (glyphosate). The potential structure-herbicidal activity relationship of these compounds was also discussed. To a certain extent, the results of this study will attract great interest for the potential practical application of promising fungal metabolites, α-pyrone derivatives, as ecofriendly herbicides.
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new cytotoxic tricycloalternarenes from fungus Alternaria brassicicola
Bioorganic Chemistry, 2019Co-Authors: Ying Tang, Weiguang Sun, Jiankun Guan, Sitian Zhang, Shuang Lin, Jianping Wang, Yonghui ZhangAbstract:Abstract Seven previously undescribed metabolites, designated as tricycloalternarenes Q–W (1–7), were isolated and identified from the fermented rice substrate of fungus Alternaria brassicicola. The planar and absolute structures of all new compounds were determined on the basis of extensive NMR spectroscopic data, a modified Mosher’s method, X-ray crystallographic analysis, and electronic circular dichroism (ECD) spectral analyses. All the isolates were evaluated for in vitro cytotoxicity against five human tumor MM231, MM468, HeLa, SW1990, and SW480 cell lines, and compounds 1, 2, 5, and 7 showed selective cytotoxicity against certain human tumor cell lines with IC50 values ranging from 12.83 to 32.87 μM, with no obvious cytotoxicity to the normal LO2 cell.
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alterbrassicicene a a highly transformed fusicoccane derived diterpenoid with potent ppar γ agonistic activity from Alternaria brassicicola
Organic Letters, 2018Co-Authors: Weiguang Sun, Jiankun Guan, Sitian Zhang, Shuang Lin, Jianping Wang, Junjun Liu, Weixi Gao, Yonghui ZhangAbstract:Alterbrassicicene A (1), a fusicoccane-derived diterpenoid with an unprecedented framework, together with two known biosynthetic intermediates (2 and 3), were characterized from Alternaria brassicicola. The absolute structure of 1 was assigned by extensive spectroscopic analyses and quantum chemical calculations. Compound 1 represents a newly transformed monocyclic carbon skeleton of a highly functionalized diterpenoid bearing unique dihydro-2(3H)-furanone and 2-cyclopenten-1-one motifs. Compound 1 was the first fusicoccane-derived diterpenoid functioning as a potent PPAR-γ agonist (EC50 = 744.1 nM).
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anti inflammatory fusicoccane type diterpenoids from the phytopathogenic fungus Alternaria brassicicola
Organic and Biomolecular Chemistry, 2018Co-Authors: Weiguang Sun, Jiankun Guan, Sitian Zhang, Shuang Lin, Jianping Wang, Junjun Liu, Weixi Gao, Hucheng Zhu, Yonghui ZhangAbstract:Altering the cultivation conditions, such as temperature, media compositions, illumination, aeration, the shape of the culturing flask, etc., is regarded as a useful strategy for the exploitation of structurally novel and bioactive secondary metabolites, which inspired us to explore the chemical and pharmacological diversities from the genetically powerful fungus Alternaria brassicicola. As a result, twelve fusicoccane-type diterpenoids, including eight new ones, termed brassicicenes Q-X (1-8), were isolated from a modified rice medium. Biosynthetically, all these compounds were derived from the mevalonic acid (MVA) pathway, and their structures incorporating absolute configurations were assigned by the interpretation of spectroscopic (HRESIMS and 1D and 2D NMR) analyses, chemical conversion, a modified Mosher's method, 13C NMR calculation, and single-crystal X-ray diffraction (Cu Kα). Structurally, compound 1 was an unusual 16-nor-dicyclopenta[a,d]cyclooctane diterpenoid bearing a fused cyclopent-2-en-1-one moiety. In addition, compound 3 was found to show significant anti-inflammatory activity against the production of NO, TNF-α, and IL-1β at 10 μM. Further western blot and immunofluorescence experiments found the mechanism of action to be that 3 inhibited the NF-κB-activated pathway, highlighting it as a promising starting point for the development of new anti-inflammatory agents.
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fusicoccane derived diterpenoids from Alternaria brassicicola investigation of the structure stability relationship and discovery of an ikkβ inhibitor
Organic Letters, 2018Co-Authors: Weiguang Sun, Ying Tang, Jiankun Guan, Jianping Wang, Junjun Liu, Yongbo Xue, Zengwei Luo, Hucheng Zhu, Yonghui ZhangAbstract:The structure–stability relationships of 1–6 were investigated to show that 1 converted to 5 via a kinetic, solution-mediated autoxidation. In addition, alterbrassicene A (7), a fusicoccane-derived diterpenoid bearing an unprecedented 5/9/4-fused carbocyclic skeleton with a rare fused 2-cyclobuten-1-one motif, was characterized from Alternaria brassicicola. Its absolute structure was elucidated by spectroscopic analyses and quantum chemical calculations. Compound 7 was the first fusicoccane derivative acting as a potent IKKβ inhibitor in the NF-κB signaling pathway.
Sitian Zhang - One of the best experts on this subject based on the ideXlab platform.
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new α pyrone derivatives with herbicidal activity from the endophytic fungus Alternaria brassicicola
Bioorganic Chemistry, 2021Co-Authors: Zhangyan Huang, Weiguang Sun, Sitian Zhang, Jianping Wang, Weixi Gao, Xia Chen, Fei Cao, Yonghui ZhangAbstract:Abstract Three pairs of undescribed enantiomeric α-pyrone derivatives (1a/1b–3a/3b) and six undescribed congeners (4–9), were obtained from the fungus Alternaria brassicicola that was isolated from the fresh leaves of Siegesbeckia pubescens Makino (Compositae). The structures of these new compounds were characterized by extensive NMR spectroscopic and HRESIMS data, and their absolute configurations were further elucidated by a modified Mosher's method, chemical conversion, single-crystal X-ray diffraction analysis, and ECD calculations. This is the first report of three pairs of enantiomeric α-pyrone derivatives from the fungus A. brassicicola, and these enantiomers were successfully acquired from scalemic mixtures via chiral HPLC. Compounds 1a/1b–3a/3b and 4–9 were evaluated for the herbicidal activity against Echinochloa crusgalli, Setaria viridis, Portulaca oleracea, and Taraxacum mongolicum. At a concentration of 100 μg/mL, compounds 1a and 1b could significantly inhibit the germination of monocotyledon weed seeds (E. crusgalli and S. viridis) with inhibitory ratios ranging from 68.6 ± 6.4% to 84.2 ± 5.1%, which was equivalent to that of the positive control (glyphosate). The potential structure-herbicidal activity relationship of these compounds was also discussed. To a certain extent, the results of this study will attract great interest for the potential practical application of promising fungal metabolites, α-pyrone derivatives, as ecofriendly herbicides.
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fusicoccane derived diterpenoids with bridgehead double bond containing tricyclo 9 2 1 03 7 tetradecane ring systems from Alternaria brassicicola
Bioorganic Chemistry, 2020Co-Authors: Lifen Pan, Sitian Zhang, Shuang Lin, Jianping Wang, Beiye Yang, Junjun Liu, Yonghui ZhangAbstract:Abstract Fusicoccane-derived diterpenoids bearing a unique bridgehead double-bond-containing tricyclo[9.2.1.03,7]tetradecane (5-9-5 ring system) core skeleton represent a rarely reported class of rearranged terpenoids, which traced back to fusicoccanes with a classical dicyclopenta[a,d]cyclooctane (5-8-5 ring system) core skeleton via a crucial Wagner-Meerwein rearrangement reaction. In this research, alterbrassicenes B–D (1–3), three new rearranged fusicoccane diterpenoids bearing a rare bridgehead double-bond-containing tricyclo[9.2.1.03,7]tetradecane core skeleton, together with two known congeners, brassicicenes O and K (4 and 5), were isolated from the modified cultures of fungus Alternaria brassicicola. Their structures were elucidated by comprehensive analyses of the NMR and HRESIMS data, and the absolute configurations of 1 and 4 were further confirmed via a combination of 13C NMR and ECD calculations and single-crystal X-ray diffraction analysis (Cu Kα). Interestingly, alterbrassicene B (1) represented the second case of bridgehead C-10–C-11 double-bond-containing natural products with a bicyclo[6.2.1]undecane core skeleton, and also featured an undescribed oxygen bridge between C-6 and C-14 to construct an unprecedentedly caged tetracyclic system. Alterbrassicenes B–D showed moderate cytotoxic activity against certain human tumor cell lines with IC50 values in the range of 15.87–36.85 μM.
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modified fusicoccane type diterpenoids from Alternaria brassicicola
Journal of Natural Products, 2020Co-Authors: Shuang Lin, Sitian Zhang, Jianping Wang, Lifen Pan, Chenwei Chai, Beiye Yang, Junjun Liu, Yonghui ZhangAbstract:Seven new modified fusicoccane-type diterpenoids (1-7), together with two known congeners (8 and 9), were obtained from Alternaria brassicicola. Their structures were elucidated from a combination of NMR and HRESIMS data and 13C NMR calculation as well as DP4+ probability analyses, and the absolute configurations of 1-5 were determined by ECD calculation and single-crystal X-ray diffraction (Cu Kα). Compounds 1-3 belong to a rare class of 16-nor-dicyclopenta[a,d]cyclooctane diterpenoids, and compounds 2 and 4 represent the first examples of fusicoccane-type diterpenoids featuring two previously undescribed tetracyclic 5/6/6/5 ring systems, while compound 5 features a previously undescribed tetracyclic 5/8/5/3 ring system. Compound 7 was moderately anti-inflammatory, and compounds 2, 3, 5, and 7 were weakly cytotoxic.
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new cytotoxic tricycloalternarenes from fungus Alternaria brassicicola
Bioorganic Chemistry, 2019Co-Authors: Ying Tang, Weiguang Sun, Jiankun Guan, Sitian Zhang, Shuang Lin, Jianping Wang, Yonghui ZhangAbstract:Abstract Seven previously undescribed metabolites, designated as tricycloalternarenes Q–W (1–7), were isolated and identified from the fermented rice substrate of fungus Alternaria brassicicola. The planar and absolute structures of all new compounds were determined on the basis of extensive NMR spectroscopic data, a modified Mosher’s method, X-ray crystallographic analysis, and electronic circular dichroism (ECD) spectral analyses. All the isolates were evaluated for in vitro cytotoxicity against five human tumor MM231, MM468, HeLa, SW1990, and SW480 cell lines, and compounds 1, 2, 5, and 7 showed selective cytotoxicity against certain human tumor cell lines with IC50 values ranging from 12.83 to 32.87 μM, with no obvious cytotoxicity to the normal LO2 cell.
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alterbrassinoids a d fusicoccane derived diterpenoid dimers featuring different carbon skeletons from Alternaria brassicicola
Organic Letters, 2019Co-Authors: Shuang Lin, Sitian Zhang, Jianping Wang, Beiye Yang, Junjun Liu, Xincai Hao, Yonghui ZhangAbstract:Alterbrassinoids A–D (1–4), the first examples of fusicoccane-derived diterpenoid dimers furnished by forming an undescribed C-12–C-18′ linkage, were isolated from modified cultures of Alternaria brassicicola. Compounds 1 and 2 represent unprecedented heterodimers, whereas 3 and 4 represent unprecedented homodimers, and 4 also features an undescribed anhydride motif. Their structures were assigned via spectroscopic methods, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Putative biosynthetic pathways and a bioactivity evaluation for 1–4 were discussed.