Phytotoxic, Antifungal and Immunosuppressive Metabolites from Aspergillus terreus QT122 Isolated from the Gut of Dragonfly.

Insect gut microbes have been considered as a resource for bioactive metabolites. The aim of this study was to characterize the compounds of a fungus Aspergillus terreus QT122 associated with the gut of dragonfly. Five main phytotoxic, antifungal, and immunosuppressive substances were isolated from the fungus QT122. The structures of such compounds were identified as emodin (1), 1-methyl emodin (2), terrein (3), methyl 6-acetyl-4-methoxy-7,8-dihydroxynaphthalene-2-carboxylate (4), and dihydrogeodin (5) on the basis of spectroscopic analysis and by comparison of the corresponding data to those reported in the literature previously. The compound 3 exhibited the best phytotoxic activity against the radicle growth of A. retroflexus L. and E. crusgalli L. with their IC50 values of 11.2 and 3.1 µg/mL, which were comparable to that of the positive control of 2,4-dichlorophenoxyacetic acid (2,4-D) with the IC50 values of 8.1 and 1.6 µg/mL, respectively. The compounds 2-3 showed potent antifungal activity in the growth of Alternaria solani with the IC50 value of less than 0.1 µg/mL and the compound 2 also had great inhibitory effect against the growth of Fusarium oxysporum f. sp. cucumerinum (IC50 < 0.1 µg/mL), which was comparable to that of referenced cycloheximide with IC50 value of below 0.1 µg/mL. The compounds 3-5 exhibited strong immunosuppressive activities against the T cell viability with the inhibition rates of more than 99%, which were comparable to positive cyclosporin A under the concentration of 20 µM. These results suggest that the compounds 2-5 have the potential to be used as bio-control agents in agriculture or immunosuppressive agents.

Photo-Controlled Macroscopic Self-Assembly Based on Photo-Switchable Hetero-Complementary Quadruple Hydrogen Bonds.

A photo-switchable hetero-complementary quadruple H-bonding array, which consists of an azobenzene-derived ureidopyrimidinone (UPy) module (Azo-UPy) and a nonphotoactive diamidonaphthyridine (DAN) derivative (Napy-1), is constructed based on a reversible photo-locking approach. Upon UV (390 nm)/Vis (460 nm) light irradiations, photo-switchable quadruple H-bonded dimerization between Azo-UPy and Napy-1 can be achieved with exhibiting 4.8×104 -fold differences in binding strength (ON/OFF ratios). Furthermore, smart polymeric gels with unique photo-controlled macroscopic self-assembly behavior can be fabricated by introducing such quadruple H-bonding array as photo-regulable noncovalent interfacial connections.

Efficient method for the synthesis of functionalized pyrazoles by catalyst-free one-pot tandem reaction of nitroalkenes with ethyl diazoacetate.

The one-pot synthesis of multisubstituted pyrazole derivatives was achieved via catalyst-free 1,3-dipolar cycloaddition of ethyl diazoacetate and nitroalkenes as the key step and elimination of the leaving group (NO(2) or Br) followed by intramolecular proton transfer with satisfactory yields.

3-Hydroxy-adamantane-1-acetic acid.

The crystal structure of the title adamantane derivative, C(12)H(18)O(3), has been determined by X-ray diffraction. The structure is stabilized by inter-molecular O-H⋯O hydrogen bonds, forming a chain.

Tunable Water-Soluble Supramolecular Polymers by Visible-Light-Regulated Host-Guest Interactions.

The development of artificial self-assembling systems with dynamic photo-regulation features in aqueous solutions has drawn great attention owing to the potential applications in fabricating elaborate biological materials. Here we demonstrate the fabrication of water-soluble cucurbit[8]uril (CB[8])-mediated supramolecular polymers by connecting the fluorinated azobenzene (FAB) containing monomers through host-enhanced heteroternary π-π stacking interactions. Benefiting from the unique visible-light-induced E→Z photoisomerization of the FAB photochromophores, the encapsulation behaviors between the CB[8] macrocycle and the monomers could be regulated upon visible light irradiation, resulting in the depolymerization of such CB[8]-mediated supramolecular polymers.

Toward bidirectional photoswitchable colored photochromic molecules with visible light stability.

Photochromic [2]rotaxanes with bidirectional photoswitchability were fabricated, whose colored states exhibit remarkable visible-light and thermal stabilities as revealed by systematically spectroscopic investigations.

[Classification of Panax quinquefolium L. and Panax ginseng C. A. Mey. based on FTIR analysis with SVM].

The support vector machine (SVM) is a new learning technique based on the statistical learning theory. In the present paper, forty Panax quinquefolium L. samples were used as experimental materials. The classification models were established using Fourier transform infrared spectra(FTIR)-SVM training method with the intention of identifying whether the Panax quinquefolium L. samples are genuine or they are just Panax ginseng C. A. Mey. samples. The thirty samples in training set were identified by the classifying models with an accurate rate of 100%, while the ten estimate samples had an accurate rate of 90%. The research result shows the feasibility of establishing the models with FTIR-SVM method to identify Panax quinquefolium L. samples and Panax ginseng C. A. Mey.

Phytotoxic and antibacterial metabolites from Fusarium proliferatum ZS07 isolated from the gut of long-horned grasshoppers.

In the proceeding of screening new bioactive natural products, the ethyl acetate extract of the fermentation broth of Fusarium proliferatum ZS07, a fungus residing in the gut of long-horned grasshoppers (Tettigonia chinensis), was found possessing selective phytotoxic activity against the radicle growth of Amaranthus retroflexus L. Bioactivity-guided fractionation lead to the isolation of six fungal metabolites 1-6, including a new polyketide derivate O-methylated SMA93 (2) and five known compounds SMA93 (1), rhodolamprometrin (3), radicinin (4), dehydroallogibberic acid (5), and 3-methyl-6,8-dihydroxyisocoumarin (6). Their structures were identified on the basis of spectroscopic analysis and by comparison of the corresponding data to those reported in the literature previously. Phytotoxic effects of the four isolated compounds 1-4 on the radicle growth of A. retroflexus L. seeds were investigated under laboratory conditions, and compounds 2 and 4 showed good phytotoxic activity in the concentration of 100 µg/mL, with the inhibition rates of 83.0 and 65.2%, respectively. Furthermore, the antibacterial activity of compounds 1-5 were evaluated against selected bacteria. Compounds 1-3 were found to possess potent antibacterial activity against Bacillus subtilis (ATCC 6633), with the minimum inhibitory concentration (MIC) values of 3.13-12.50 µg/mL, while Escherichia coli (ATCC 8739) and Salmonella typhimurium [CMCC(B) 50115] were not susceptible. These results suggest that the new polyketide derivate 2 and known compounds 1, 3, and 4 have potential to be used as biocontrol agents in agriculture.

Antifungal activities of metabolites produced by a termite-associated Streptomyces canus BYB02.

Two main antifungal metabolites resistomycin and tetracenomycin D were isolated and purified from a termite-associated Streptomyces canus BYB02 by column chromatography. The structures of isolated compounds were determined on the basis of extensive spectroscopic analysis. Resistomycin possessed strong activities against mycelial growth of Valsa mali (IC(50) = 1.1 µg/mL) and Magnaporthe grisea (IC(50) = 3.8 µg/mL), which were comparable to those of referenced cycloheximide, with IC(50) values of 2.3 and 0.3 µg/mL, respectively. A further spore germination test showed that resistomycin exhibited potent reduction in spore germination for M. grisea , with an IC(50) value of 5.55 µg/mL. Finally, the in vivo antifungal activity experiment showed that resistomycin possessed significant preventive efficacy against rice blast, which was more potent than that of referenced carbendazim, with control efficacies of 66.8 and 58.7%, respectively. The present results suggest that resistomycin has potential to be used as a fungicide.

Extraction optimisation, purification and major antioxidant component of red pigments extracted from Camellia japonica.

The optimised extraction conditions of red pigments (RP) from Camellia japonica obtained with an orthogonal design L9(34) were solid/liquid ratio, temperature, pH and extraction time as 1/10, 60°C, 1.5 and 4h, respectively. The RP were then purified by the macroporous resin method, which showed the resin LX-68 was appropriate for purifying the pigments from C. japonica. The antioxidant activities of these pigments were also investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical in vitro model systems. The DPPH scavenging activity of pigment extract was comparable to that of standard butylated hydroxyanisole (BHA). The IC50 values of the RP and BHA were 4.55 and 4.17µgml-1, respectively. The pigments showed higher hydroxyl radical-scavenging activities than that of mannitol at the same concentration. Following activity-oriented separation, (-)-epicatechin was isolated as an active principle, which exhibited excellent DPPH free radical scavenging activities with IC50 5.08µgml-1.

Phytotoxic and antifungal metabolites from Curvularia sp. FH01 isolated from the gut of Atractomorpha sinensis.

Two main phytotoxic and antifungal phthalic acid butyl isobutyl ester (1) and radicinin (2) were isolated from the culture of Curvularia sp. FH01, a fungus residing in the Atractomorpha sinensis gut. The structures of isolated metabolites were established on the basis of spectral analysis. Metabolites 1 and 2 exhibited significant phytotoxic activity against the radical growth of Echinochloa crusgalli with their IC(50) values of 61.9 and 5.9 µg/mL, respectively, which were comparable to that 2,4-dichlorophenoxyacetic acid (2.0 µg/mL) used as a positive control. The antifungal test results showed that compound 2 possessed strong antifungal activity against Magnaporthe grisea (IC(50)=16.3 µg/mL) and Valsa mali (IC(50)=18.2 µg/mL). The findings of the present study suggest that bioactive properties of the fungus FH01 can be attributed to its major components, phthalic acid butyl isobutyl ester and radicinin, and both agents have a potential to be used as herbicide and fungicide.