7 research outputs found
Festuca loliacea
Three new <i>ent</i>-eudesmane sesquiterpenoids,
arundinols
A–C (<b>1</b>–<b>3</b>), one isochroman-1-one,
arundinone A (<b>4</b>), and a polyoxygenated benzofuran-3Â(2<i>H</i>)-one dimer, arundinone B (<b>5</b>), were isolated
from the extract of a plant endophytic fungus, <i>Microsphaeropsis
arundinis</i>. Their structures were elucidated primarily by
NMR experiments, and <b>1</b> was confirmed by X-ray crystallography.
The absolute configuration of <b>1</b> was assigned by X-ray
crystallography using Cu Kα radiation, whereas those of the
C-11 tertiary alcohols in <b>2</b> and <b>3</b> were deduced
via the circular dichroism data of the in situ formed [Rh<sub>2</sub>(OCOCF<sub>3</sub>)<sub>4</sub>] complexes. Arundinone B (<b>5</b>) represents the first dimeric benzofuran-3Â(2<i>H</i>)-one,
showing cytotoxicity against T24 and A549 cells. The co-isolated known
compound <b>6</b> showed a modest inhibitory effect against <i>Staphylococcus aureus</i>
Presentation1.pdf
<p>With a layered structure, layered double hydroxide (LDH) has potential applications in remediation of anionic contaminants, which has been a hot topic for recent years. In this study, a Cl type Mg-Al hydrotalcite (Cl-LDH) was prepared by a co-precipitation method. The adsorption process of three pharmaceuticals and personal care products (PPCPs) [tetracycline (TC), diclofenac sodium (DF), chloramphenicol (CAP)] by Cl-LDH was investigated by X-ray diffraction (XRD), Zeta potential, dynamic light scattering (DLS), BET, Fourier transform infrared (FTIR) spectroscopy, and molecular dynamics simulation. The results showed that the adsorption equilibrium of TC and DF could be reached in 120 min, and the maximum adsorption capacity of the TC and DF were 1.85 and 0.95 mmol/g, respectively. The isothermal adsorption model of TC was fitted with the Freundlich adsorption model, and the isothermal adsorption model of DF was fitted with the Langmuir adsorption model. The adsorption dynamics of TC and DF followed the pseudo-second-order model. The adsorption mechanisms of the three PPCPs into Cl-LDH were different based on the experimental results and molecular dynamics simulation. The TC adsorption on Cl-LDH was accompanied by the electrostatic interactions between the negative charge of TC and the positive charge of Cl-LDH. The uptake of DF was attributed to anion exchange and electrostatic interaction. Cl-LDH does not adsorb CAP due to no electrostatic interaction. The molecular dynamic simulation further confirmed different configurations of three selected PPCPs, which were ultimately responsible for the uptake of PPCPs on Cl-LDH.</p
A Spiro[chroman-3,7′-isochromene]-4,6′(8′<i>H</i>)-dione from the Cordyceps-Colonizing Fungus Fimetariella sp.
Fimetarone A (<b>1</b>), a metabolite with the new spiro[chroman-3,7′-isochromene]-4,6′(8′<i>H</i>)-dione skeleton, was isolated from cultures of the Cordyceps-colonizing fungus Fimetariella sp. Compound <b>1</b> was a 1:1 atropdiastereomeric mixture in NMR data, and a<i>S</i>,9<i>S</i> and a<i>R</i>,9<i>R</i> enantiomers were found and confirmed by X-ray crystallography. Compound <b>1</b> could be derived from the hypothetical precursors 3,4,5-trihydroxy-2-(2-methylene-3,5-dioxohexanoyl)benzoic acid (<b>5</b>) and lapidosin (<b>6</b>)
A new sesquiterpene from the entomogenous fungus <i>Phomopsis amygdali</i>
<div><p>A new sesquiterpene, (+)-<i>S</i>-1-methyl-abscisic-6-acid (<b>1</b>), together with five known compounds, (+)-<i>S</i>-abscisic acid (<b>2</b>), fusicoccin J (<b>3</b>), 3α-hydroxyfusicoccin J (<b>4</b>), (<i>R</i>)-5-hydroxymethylmellein (<b>5</b>) and 4-hydroxyphenethyl acetate (<b>6</b>) was isolated from the fermentation extract of <i>Phomopsis amygdali</i>, an entomogenous fungus isolated from <i>Call midge</i>. Their structures were determined mainly by analysis of MS and NMR spectroscopic data. Compounds <b>1</b>–<b>6</b> were tested for antimicrobial activity against three plant pathogenic fungi: <i>Gibberella zeae</i>, <i>Verticillium albo-atrum</i>, and <i>Fusarium nivale</i>, and two bacteria: <i>Escherichia coli</i> and <i>Pseudomonas aeruginosa</i> 2033E. As a result, compounds <b>1</b>–<b>4</b> displayed antibacterial activity against Gram-negative <i>P. aeruginosa</i> 2033E, and the minimum inhibition concentration (MIC value) of <b>1</b>–<b>4</b> is 30 μg/mL, 58 μg/mL, 26 μg/mL, and 26 μg/mL, respectively.</p></div
Characterization of a Prenyltransferase for Iso-A82775C Biosynthesis and Generation of New Congeners of Chloropestolides
Chloropupukeananin
and chloropestolides are novel metabolites of
the plant endophyte <i>Pestalotiopsis fici</i>, showing
antimicrobial, antitumor, and anti-HIV activities. Their highly complex
and unique skeletons were generated from the coisolated pestheic acid
(<b>1</b>) and iso-A82775C (<b>10</b>) based on our previous
studies. Here, we identified the biosynthetic gene cluster <i>iac</i> of <b>10</b> and characterized an <i>iacE</i> encoded prenyltransferase. Deletion of <i>iacE</i> abolished
iso-A82775C production, accumulated the prenyl group-lacking siccayne
(<b>2</b>), and generated four new chloropestolides (<b>3</b>–<b>6</b>). Compounds <b>5</b> and <b>6</b> showed antibacterial effects against <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i>, and <b>5</b> was also
cytotoxic to human tumor cell lines HeLa, MCF-7, and SW480. These
results provided the first genetic and biochemical insights into the
biosynthesis of natural prenylepoxycyclohexanes and demonstrated the
feasibility for generation of diversified congeners by manipulating
the biosynthetic genes of <b>10</b>
Decalin-Containing Tetramic Acids and 4‑Hydroxy-2-pyridones with Antimicrobial and Cytotoxic Activity from the Fungus <i>Coniochaeta cephalothecoides</i> Collected in Tibetan Plateau (Medog)
New
tetramic acid derivatives, (±)-conipyridoins A–D
(<b>1</b>–<b>4</b>), conipyridoins E (<b>5</b>) and F (<b>6</b>), and new 4-hydroxy-2-pyridone alkaloids
(±)-didymellamide E (<b>7</b>), (+)-didymellamide B (<b>8</b>), (+)-<i>N</i>-hydroxyapiosporamide (<b>9</b>), and didymellamides F–H (<b>10</b>–<b>12</b>) were isolated and identified from the solid culture of the fungus <i>Coniochaeta cephalothecoides</i>. Chiral resolution of <b>1</b>, <b>2</b>, <b>3</b>, <b>4</b>, and <b>7</b> gave five pairs of enantiomers: <b>1a/1b</b>, <b>2a/2b</b>, <b>3a/3b</b>, <b>4a/4b</b>, and <b>7a/7b</b>, respectively. Stereochemistry of <b>1a</b> and <b>1b</b>, and <b>2a</b> and <b>2b</b> was established and confirmed
by the single-crystal X-ray diffraction and electronic circular dichroism
(ECD) methods. Absolute configuration in <b>3a</b>, <b>3b</b>, <b>4a</b>, <b>4b</b>, <b>7a,</b> and <b>7b</b> was assigned by ECD calculations. Compounds <b>1</b>–<b>6</b> possess an unprecedented chemical skeleton featuring a decalin
ring and a tetramic acid moiety. Compound <b>11</b> significantly
inhibited the growth of <i>Candida albicans</i> and <i>Aspergillus fumigatus</i> with minimum inhibitory concentration
(MIC) of 3.13 and 1.56 μM, respectively, and was further confirmed
to be a new chitin synthesis inhibitor. Compound <b>5</b> exhibited
the strongest activity against the growth of both <i>Staphylococcus
aureus</i> and MRSA with MIC value of 0.97 μM. In the light
of a co-occurrence of 3-acyl tetramic acids and biogenetically related
pyridine alkaloids, the biosynthetic pathway for <b>1</b>–<b>12</b> was postulated
Decalin-Containing Tetramic Acids and 4‑Hydroxy-2-pyridones with Antimicrobial and Cytotoxic Activity from the Fungus <i>Coniochaeta cephalothecoides</i> Collected in Tibetan Plateau (Medog)
New
tetramic acid derivatives, (±)-conipyridoins A–D
(<b>1</b>–<b>4</b>), conipyridoins E (<b>5</b>) and F (<b>6</b>), and new 4-hydroxy-2-pyridone alkaloids
(±)-didymellamide E (<b>7</b>), (+)-didymellamide B (<b>8</b>), (+)-<i>N</i>-hydroxyapiosporamide (<b>9</b>), and didymellamides F–H (<b>10</b>–<b>12</b>) were isolated and identified from the solid culture of the fungus <i>Coniochaeta cephalothecoides</i>. Chiral resolution of <b>1</b>, <b>2</b>, <b>3</b>, <b>4</b>, and <b>7</b> gave five pairs of enantiomers: <b>1a/1b</b>, <b>2a/2b</b>, <b>3a/3b</b>, <b>4a/4b</b>, and <b>7a/7b</b>, respectively. Stereochemistry of <b>1a</b> and <b>1b</b>, and <b>2a</b> and <b>2b</b> was established and confirmed
by the single-crystal X-ray diffraction and electronic circular dichroism
(ECD) methods. Absolute configuration in <b>3a</b>, <b>3b</b>, <b>4a</b>, <b>4b</b>, <b>7a,</b> and <b>7b</b> was assigned by ECD calculations. Compounds <b>1</b>–<b>6</b> possess an unprecedented chemical skeleton featuring a decalin
ring and a tetramic acid moiety. Compound <b>11</b> significantly
inhibited the growth of <i>Candida albicans</i> and <i>Aspergillus fumigatus</i> with minimum inhibitory concentration
(MIC) of 3.13 and 1.56 μM, respectively, and was further confirmed
to be a new chitin synthesis inhibitor. Compound <b>5</b> exhibited
the strongest activity against the growth of both <i>Staphylococcus
aureus</i> and MRSA with MIC value of 0.97 μM. In the light
of a co-occurrence of 3-acyl tetramic acids and biogenetically related
pyridine alkaloids, the biosynthetic pathway for <b>1</b>–<b>12</b> was postulated