Bioactive chemical constituents from the marine-derived fungus Cladosporium sp.DLT-5

A new isochromanone,cladosporinisochromanone(1),accompanied by 15 known compounds(2–16)were obtained from secondary metabolites produced by marine-derived fungus Cladosporium sp.DLT-5.NMR and HRESIMS spectra elucidation determined the planar structure of 1.Subsequent electronic circular dichroism(ECD)experiment assigned the absolute configuration of 1.Compounds 1,2,4–6,and 10 displayed different degrees of neuroprotective activities on human neuroblastoma cells SH-SY5Y.Five compounds(1,3–5,and 13)emerged resistance to protein tyrosine phosphatase 1B(PTP1B),further kinetic analysis and molecular docking study indicated that the most potent compound 13(IC50value of 10.74±0.61μmol/L)was found as a noncompetitive inhibitor for PTP1B.Surface plasmon resonance(SPR)and molecular docking studies also demonstrated the interaction between compound 12 and Niemann-Pick C1 Like 1(NPC1L1),which has been identified as significant therapeutic target for hypercholesteremia.In addition,compounds 3,6,and 14 showed attractive inhibitory activity against the phytopathogenic fungi:Colletotrichum capsici.Therefore,library of Cladosporium metabolites is enriched and new active uses of known compounds are explored.

Isolation and identification of multidrug-resistant Staphylococcus haemolyticus from a laboratory-breeding mouse

Objective:To analysis and identify a bacterium strain isolated from laboratory breeding mouse far away from a hospital.Methods:Phenotype of the isolate was investigated by conventional microbiological methods,including Gram-staining,colony morphology,tests for haemolysis, catalase,coagulase,and antimicrobial susceptibility test.The meek and 16S rRNA genes were amplified by the polymerase chain reaction(PCR) and sequenced.The base sequence of the PCR product was compared with known 16S rRNA gene sequences in the CenBank database by phylogenetic analysis and multiple sequence alignment.Results:The isolate in this study was a gram positive,coagulase negative,and catalase positive coccus.The isolate was resistant to oxacillin,methicillin,penicillin,ampicillin,cefazolin,cipr of loxacin erythromycin,et al.PCR results indicated that the isolate was meek gene positive and its 16S rRNA was 1465 bp.Phylogenetic analysis of the resultant 16S rRNA indicated the isolate belonged to genus Saphylococcus,and multiple sequence alignment showed that the isolate was Saphylococcus haemolyticus with only one base difference from the corresponding 16S rRNA deposited in the CenBank.Conclusions: 16S rRNA gene sequencing is a suitable technique for non-specialist researchers.Laboratory animals are possible sources of lethal pathogens,and researchers must adapt protective measures when they manipulate animals.

Catechol-derived Inhibitors against Quorum Sensing from Retiboletus kauffmanii

[Objectives]This study aimed to screen anti-quorum sensing(QS)activity from the constituent of Retiboletus kauffmanii fruit body.[Methods]Chromatographic technology was used to isolate compounds,while well diffusion assay was applied to screen anti-quorum sensing activity.[Results]12 phenolic compounds were purified from extracts,three catechol-derived compounds at sub-inhibitory concentrations were found to inhibit the production of violacein in Chromobacterium violaceum for the first time.[Conclusions]Three catechol analogs isolated from R.kauffmanii fruit body extract were indicated as quorum sensing inhibitors against C.violaceum.

New indole derivatives from endophytic fungus Colletotruchum sp. HK-08 originated from leaves of Nerium indicum

Objective: To study secondary metabolites from endophytic fungus Colletotruchum sp. HK-08 originated from the leaves of Nerium indicum.Methods: The compounds were isolated by various column chromatographic techniques, and their structures were elucidated by spectroscopic techniques [high resolution electrospray ionization mass spectroscopy(HRESIMS), one-dimensional(1D) and two-dimensional(2D) nuclear magnetic resonance spectroscopy(NMR)], as well as comparison with literature data. The Ellman method was used to determine the acetylcholinesterase(ACh E) inhibitory activity.Results: Four indole derivatives were identified from Colletotruchum sp. HK-08, including 6’-hydroxymonaspiloindole(1), 2-(2-oxoindolin-3-yl)ethyl 2-(4-hydroxyphenyl) acetate(2), 2-(2-oxoindolin-3-yl)ethyl 2-(2-hydroxyphenyl)acetate(3), and monaspiloindole(4). Compound 4 presented weak ACh E inhibitory activity with IC50value of(69.30 ± 6.27) μmol/L [tacrine as the positive control, with IC50value of(0.61 ± 0.07) μmol/L].Conclusion: Compounds 1–3 were new compounds, and compound 4 had weak ACh E inhibitory activity.

Chemical constituents from agarwood of Aquilaria filaria

Investigations on the chemical constituents from the ethanol extract of the agarwood originating from Aquilaria filaria led to the isolation of 26 compounds by column chromatography,including silica gel,Sephadex LH-20,and semi-preparative high-performance liquid chromatography.Their structures were determined to beβ-sitostenone(1),24α-ethyl-cholestan-3α-ol(2),ergosta-4,6,8(14),22-tetraene-3-one(3),gypsogenin(4),hederagenin(5),17αH-trisnorhopanone(6),lupeol(7),friedelin(8),(-)-episyringaresinol(9),(-)-syringaresinol(10),5-hydroxy-7,4′-dimethoxyflavone(11),5,4’-dihydroxy-7,3′-dimethoxyflavone(12),2′-hydroxy-4,3′,6′,4′′-tetramethoxy-p-terphenyl(13),scopularide A(14),4-(4-hydroxyphenyl)butan-2-one(15),zingerone(16),coniferaldehyde(17),scopoletin(18),acetovanillon(19),isovanillin(20),vanillin(21),p-hydroxybenzaldehyde(22),p-hydroxybenzoic acid(23),protocatechuic acid(24),vanillic acid(25)and 4,5-dihydroxy-3-methoxybenzoic acid(26)by using spectroscopic techniques.All compounds were isolated from agarwood of A.filaria for the first time,and this was also the first report about the isolation of compounds 2,4,6,7,9,10,13-15,17-20,22,24 and 26 from agarwood and Aquilaria plants.