Study on Induction of Microcystis aeruginosa Cell Apoptosis by Signal Molecule N-acetyl-homoserine Lactones(AHLs)

[Objective]The relationship between signal molecule N-acety-homoserine lactones（AHLs） and Microcystis aeruginosa cell apoptosis was studied.[Method]With M.aeruginosa as the test materials treated by 5 μmol/L N-acety-homoserine lactones（AHLs）,the morphology of cell apoptosis was observed through staining with DAPI.[Result]Microcystis aeruginosa cell apoptosis was induced by signal molecule N-acetyhomoserine lactones（AHLs） with the concentration of 1 μmol/L to inhibit the growth and proliferation of Microcystis aeruginosa.[Conclusion] The results provided the important scientific basis and new management ideas for the treatment of water bloom of Microcystis aeruginosa.

New Sesquiterpene Lactones from Carpesium Lipskyi

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Synthesis of 2,5-disubstituted tetrahydrofurans from organozinc halides and lactones

2,5-Disubstituted tetrahydrofurans were obtained from lactones and organozinc halides in moderate to high yield in the presence of Lewis acids.

Two New Eremophilane Sesquiterpene Lactones from Ligularia myriocephala Ling

Two new eremophilane sesquiterpene lactones, 1β-angeloyloxy-6β, 10β-dihydroxy-8β- methoxyeremophila-7（ll）en-8α,12-olide and 1β-angeloyloxy-6β,10α-dihydroxy-8α-methoxyeremo- phila-7（ 11）en-8β, 12-olide were isolated from the extract of the whole plant of Ligularia myriocephala Ling. Their structures and stereochemistry were elucidated by various spectroscopic methods including intensive 2D-NMR techniques （COSY, gHMQC, gHMBC and ^1H-^1H NOESY） and HR-ESIMS.

Synthesis of Macrocyclic Lactones Building on Double Calix[4]arenes

The macrocyclic lactones building on calix[4]arenes 3a-b and double calix[4]arenes 4a-b were synthesized by the reaction of p-tert-butylcalix[4]arene (1a) or calix[4]arene (1b) with glycol bis(2-chloroacetate) (2). The conditions to improve the yields of double calix[4]arenes have been discussed.

PREPARATION OF ENANTIOMERICALLY PURE SYN-4,5-DIHYDROXY CARBOXYLIC ACID LACTONES BY MICROBIAL REDUCTION

Enantiomerically pure syn-4,5-dihydroxy carboxylic acid lactones were prepared by microbial reduction of acyl lactones with resting cell of Aspergillus niger.

STUDIES ON CYCLOPENT-2-ENONE: (Ⅳ)PREPARATION OF UNSATURATED δ-LACTONES FROM THE ALDOLS OF CYCLOPRNT-2-ENONE

A new route was developed for diastereoselective preparation of δ-(α-hydroxyalkyl)-αβ-unsaturated δ-lactones. A single diastereoisomer(14) of the lactone was obtained after oxidation and elimination of (12).

THE STUDY OF ENZYMATIC SYNTHESIS OF MACROCYCLIC LACTONES

The effects of the chain length and stereo-factor of substrates and solvents on the lipase catalysed lactonization of ω-hydroxy-ester were studied, And also the catalytic effects of various enzymes were compared.

Sesquiterpene Lactones from Notoscris Porphyrolepis

Two new sesquiterpcne lactones, notoserolides A and B. along with 12 known compounds were isolated from the aerial parts of Notoseris porphyrolepis. By means of spectral methods including MS. NMR (1H NMR. 13C NMR. DEPT. HMQC. HMBC) and X-ray diffraction. as well as chemical reactions. the structures of notoserolides A and B were established as auslricin 8-O-β-D-glucopyranoside and 8-O-senecioylaustricin. respectively.

N-Acylhomoserine Lactones (AHLs), QseB/C Gene Detection, Virulence Factors and Antibiotics Resistance of <i>Aeromonas hydrophila</i>

The aim of this research was to detect the N-acyl homoserine lactones (AHLs) production and QseB/C gene of Aeromonas hydrophila. We analyzed the potentials of these isolates of Aeromonas hydrophila in causing biofilm formation, hemolysis, protease, and lipase. The antibiotic susceptibility of the 15 Aeromonas hydrophila isolates was also investigated. The detection of AHLs was carried out using the Chromobacterium violaceum strain CV026 as biosensors. The isolated strains were tested for the reaction of C. violaceum CV026 by cross-streaking on an agar plate. Production of AHLs was determined by the diffusing via the agar plates and the tinge of the biosensor strains. All isolated strains produced AHLs. A polymerase chain reaction (PCR) showed the isolated strains had qseB and qseC genes. Susceptibility tests of A. hydrophila isolates were administered against 25 different antibiotic disks representing 12 classes of antibiotics. The strains were highly resistant to β-Lactam with 96.7% showing resistibility, whereas 97.7% susceptibility was found towards Aminoglycoside class of the antibiotic used. 60% showed intermediate resistant to Polypeptide. 100% of the strains showed no resistant to Aminoglycoside, Polypeptide, Monobactam, and Carbapenems class of antibiotics. Each of the isolates was found to be associated with at least one virulent factor. Our results clearly demonstrated that there is a presence of QseB/C genes in A. hydrophila and also produces AHLs molecule and virulence factors. The investigated isolates showed the pathogenic potential of Aeromonas hydrophila which makes it a serious threat to public health.

Sesquiterpene Lactones from Elephantopus scaber

A new germacranolide sesquiterpene lactone, isoscabertopin, was isolated from Elephantopus scaber together with the known scabertopin. Their structures were determined by spectroscopic methods.

Synthesis of macrocyclic lactones with methoxysulfonyl side chain

Two representative macrocyclic lactones with methoxysulfonyl side chain（5a and 5b）were synthesized employing Michael addition with acrolein and ring enlargement as the key steps,starting from potassium,α-oxocycloaikylsulfonates（1）in total yields of 45 and 57%,respectively.

Occurrence of <i>N</i>-Acyl Homoserine Lactones in Extracts of Bacterial Strain of <i>Pseudomonas aeruginosa</i>and in Sputum Sample Evaluated by Gas Chromatography–Mass Spectrometry

This study presents a fast, accurate and sensitive technique using gas chromatography-mass spectrometry (GC-MS) for the identification and quantification of N-acyl homoserine lactones (AHLs) in the extracts of bacterial strain of Pseudomonas aeruginosa and sputum sample of a cystic fibrosis patient. This method involves direct separation and determination of AHLs by using GC-MS as simultaneous separation and characterization of AHLs were possible without any prior derivatiza-tion. Electron ionization resulted in a common fragmentation pattern with the most common fragment ion at m/z 143 and other minor peaks at 73, 57 and 43. The limit of detection for N-butanoyl, N-hexanoyl, N-octanoyl, N-decanoyl, N-dodecanoyl and N-tetradecanoyl homoserine lactones was 2.14, 3.59, 2.71, 2.10, 2.45 and 2.34 μg/L, respectively. The presence of AHLs in the culture of P. aeruginosa strain and spu-tum of a cystic fibrosis patient was achieved in selected ion monitoring (SIM) mode by using the prominent fragment at m/z 143.

Two New Lactones Metabolized from Isoline by Rat Liver Microsomes

Two new metabolites, namely bisline lactone and isolinecic acid lactone, were isolated from the resultant incubates after a scale-up incubation of isoline with rat liver microsomes. Their structures were determined by spectroscopic data, especially those from 1D and 2D NMR experiments.

Synthesis of Z and E-(2',5'-dimethoxyphenyl)-methylene-butyrolactones

A pair of Z and E isomers of cyclization of γ-ketoacid 7, which was prepared in six steps from 2,5-dimethoxyphenyl acetic acid 1, gave a pair of Z(20%) and E (4%) isomers of (2,5-dimethoxyphenyl)-methylene-butyrolactones

Small moleculeα-methylene-γ-butyrolactone,an evolutionarily conserved moiety in sesquiterpene lactones,ameliorates arthritic phenotype via interference DNA binding activity of NF-κB

Rheumatoid arthritis(RA)is an inflammatory disease accompanied by abnormal synovial microenvironment(SM).Sesquiterpene lactones(SLs)are the main anti-inflammatory ingredients of many traditional herbs utilized in RA treatment.α-Methylene-γ-butyrolactone(α-M-γ-B)is a core moiety that widely exists in natural SLs.This study was designed to investigate the anti-arthritic potential ofα-M-γ-B as an independent small molecule in vitro and in vivo.α-M-γ-B exhibited stronger electrophilicity and anti-inflammatory effects than the other six analogs.α-M-γ-B inhibited the production of pro-inflammatory mediators via repolarizing M1 macrophages into M2 macrophages.The transcriptome sequencing suggested thatα-M-γ-B regulated the immune system pathway.Consistently,α-M-γ-B attenuated collagen type II-induced arthritic(CIA)phenotype,restored the balance of Tregs-macrophages and remodeled SM via repolarizing the synovial-associated macrophages in CIA mice.Mechanistically,althoughα-M-γ-B did not prevent the trans-nucleus of NF-κB it interfered with the DNA binding activity of NF-κB via direct interaction with the sulfhydryl in cysteine residue of NF-κB p65,which blocked the activation of NF-κB.Inhibition of NF-κB reduced the M1 polarization of macrophage and suppressed the synovial hyperplasia and angiogenesis.α-M-γ-B failed to ameliorate CIA in the presence of N-acetylcysteine or when the mice were subjected to the macrophage-specific deficiency of Rela.In conclusion,α-M-γ-B significantly attenuated the CIA phenotype by directly targeting NF-κB p65 and inhibiting its DNA binding ability.These results suggest thatα-M-γ-B has the potential to serve as an alternative candidate for treating RA.The greater electrophilicity ofα-M-γ-B,the basis for triggering strong anti-inflammatory activity,accounts for the reason whyα-M-γ-B is evolutionarily conserved in the SLs by medical plants.

Three rare anti-inflammatory sesquiterpene lactones from Magnolia grandiflora

Four new sesquiterpene lactones(SLs)(1–4),along with a biosynthetically related SL(5),have been isolated from the leaves of Magnolia grandiflora.Magrandate A(1)is notable as the first C18 homogemarane type SL,featuring a unique 1,7-dioxaspiro[4.4]nonan-6-one core.Compounds 2 and 3,representing the first instances of chlorine-substituted gemarane-type SL analogs in natural products,were also identified.The structures of these isolates were elucidated through a combination of spectroscopic data analysis,electronic circular dichroism calculations,and X-ray single-crystal diffraction analysis.All isolates demonstrated anti-inflammatory activity in lipopolysaccharide-stimulated RAW264.7 cells.Notably,3–5 showed a significant inhibitory effect on nitric oxide production,with IC50 values ranging from 0.79 to 4.73μmol·L^(−1).Additionally,4 and 5 exhibited moderate cytotoxic activities against three cancer cell lines,with IC50 values between 3.09 and 11.23μmol·L^(−1).

Anti-inflammatory germacrane-type sesquiterpene lactones from Vernonia sylvatica

Nine new germacranolides,sylvaticalides A−H(1-9),and three known analogues(10-12)were isolated from the aeri-al part of Vernonia sylvatica.Their structures were established using comprehensive spectroscopic analysis,including high-resolution electrospray ionization mass spectroscopy(HR-ESI-MS)and 1D and 2D nuclear magnetic resonance(NMR)spectra.Their absolute configurations were determined by X-ray diffraction experiments.The anti-inflammatory activities of all isolated compounds were as-sessed by evaluating their inhibitory effects on the nuclear factor kappa B(NF-κB)pathway,which was activated by lipopolysacchar-ide(LPS)-stimulated human THP1-Dual cells,and the interferon-stimulated gene(ISG)pathway,activated by STING agonist MSA-2 in the same cell model.Compounds 1,2 and 6 showed inhibitory effects on the NF-κB and ISG signaling pathways,with IC_(50)values ranging from 4.12 to 10.57μmol·L^(−1).

Pharmacokinetics of the prototype and hydrolyzed carboxylic forms of ginkgolides A, B, and K administered as a ginkgo diterpene lactones meglumine injection in beagle dogs

Ginkgo diterpene lactones meglumine injection(GDLI)is a commercially available product used for neuroprotection.However,the pharmacokinetic properties of the prototypes and hydrolyzed carboxylic forms of the primary components in GDLI,i.e.,ginkgolide A(GA),ginkgolide B(GB),and ginkgolide K(GK),have never been fully evaluated in beagle dogs.In this work,a simple,sensitive,and reliable method based on ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS)was developed,and the prototypes and total amounts of GA,GB,and GK were determined in beagle dog plasma.The plasma concentrations of the hydrolyzed carboxylic forms were calculated by subtracting the prototype concentrations from the total lactone concentrations.For the first time,the pharmacokinetics of GA,GB,and GK were fully assessed in three forms,i.e.,the prototypes,the hydrolyzed carboxylic forms,and the total amounts,after intravenous administration of GDLI in beagle dogs.It was shown that ginkgolides primarily existed in the hydrolyzed form in plasma,and the ratio of hydrolysates to prototype forms of GA and GB decreased gradually to a homeostatic ratio.All of the three forms of the three ginkgolides showed linear exposure of AUC to the dosages.GA,GB,and GK showed a constant half-life approximately 2.7,3.4,and 1.2 h,respectively,which were consistent for the forms at three dose levels(0.3,1.0,and 3.0 mg·kg^(-1))and after a consecutive injection of GDLI for 7 days(1.0 mg·kg^(-1)).

Two new diterpenoid lactones isolated from Andrographis paniculata

In the present study, two new diterpenoid lactones, 3-deoxy-andrographoside(1) and 14-deoxy-15-methoxy-andrographolide(2), were isolated from the aerial parts of Andrographis paniculata. Their structures were elucidated by combination of NMR, MS, and chemical methods. The configurations of 1 and 2 were established based on the analysis of ROESY data and single crystal X-ray diffraction experiment.