Highly oxygenated polyketides produced by Trichoderma koningiopsis QA-3, an endophytic fungus obtained from the fresh roots of the medicinal plant Artemisia argyi.

Eight new highly oxygenated fungal polyketides, namely, 15-hydroxy-1,4,5,6-tetra-epi-koninginin G (1), 14-hydroxykoninginin E (2), koninginin U (3), 4'-hydroxykoninginin U (4), koninginin V (5), 14-ketokoninginin B (6), 14-hydroxykoninginin B (7), and 7-O-methylkoninginin B (8), together with six known related analogues (9-14), were isolated from Trichoderma koningiopsis QA-3, a fungus obtained from the inner root tissue of the well known medicinal plant Artemisia argyi. All these compounds are bicyclic polyketides, with compound 1 contains unusual hemiketal moiety at C-5 and compounds 2-14 having ketone group at C-1 and double bond at C-5(6). The structures and absolute configurations of the new compounds were established by spectroscopic analysis, X-ray crystal diffraction, modified Mosher's method, and ECD calculation. The absolute configurations of the known compounds 9, 10, and 12 were determined by X-ray crystal diffractions for the first time. The antimicrobial activities against human pathogen, marine-derived aquatic bacteria, and plant-pathogenic fungi of compounds 1-14 were evaluated, and compound 1 showed remarkable activity against aquatic pathogen Vibrio alginolyticus with MIC value 1 µg/mL, which is as active as that of the positive control.

Polyketides and Terpenoids with Potent Antibacterial Activities from the Artemisia argyi-Derived Fungus Trichoderma koningiopsis QA-3.

The AcOEt extract of Artemisia argyi-derived fungus Trichoderma koningiopsis QA-3 showed potent inhibitory activity against pathogenic bacteria. Fractionation of the extract resulted in the isolation of three new polyketides (1-3) and two new terpenoids (4 and 5), together with three known metabolites (6-8). Their chemical structures were analyzed by NMR spectra, ECD, HR-ESI-MS or HR-EI-MS, optical rotation, and X-ray crystallographic data, as well as by comparison with literature reports. In the antibacterial assays, 3-hydroxyharziandione (4) showed potent activity against human pathogen Escherichia coli with an MIC value of 0.5 µg/mL, while 6-(3-hydroxypent-1-en-1-yl)-2H-pyran-2-one exhibited strong activity against marine-derived aquatic pathogen Micrococcus luteus with an MIC value of 1.0 µg/mL.

Trichocadinins B-G: Antimicrobial Cadinane Sesquiterpenes from Trichoderma virens QA-8, an Endophytic Fungus Obtained from the Medicinal Plant Artemisia argyi.

Trichocadinins B-G (1-6), six new cadinane-type sesquiterpene derivatives, each with C-14 carboxyl functionality, were isolated from the culture extract of Trichoderma virens QA-8, an endophytic fungus obtained from the fresh inner tissue of the medicinal plant Artemisia argyi. Their structures were elucidated by interpretation of the NMR spectroscopic and mass spectrometric data. The structures and absolute configurations of compounds 1 and 3 were confirmed by X-ray crystallographic analysis. Compounds 1-3 showed antibacterial and antifungal activity.

Isolation and Characterization of Antibacterial Carotane Sesquiterpenes from Artemisia argyi Associated Endophytic Trichoderma virens QA-8.

Carotane sesquiterpenes are commonly found in plants but are infrequently reported in the fungal kingdom. Chemical investigation of Trichoderma virens QA-8, an endophytic fungus associated with the inner root tissue of the grown medicinal herb Artemisia argyi H. Lév. and Vaniot, resulted in the isolation and characterization of five new carotane sesquiterpenes trichocarotins I-M (1-5), which have diverse substitution patterns, and seven known related analogues (6-12). The structures of these compounds were established on the basis of a detailed interpretation of their NMR and mass spectroscopic data, and the structures including the relative and absolute configurations of compounds 1-3, 5, 9, and 10 were confirmed by X-ray crystallographic analysis. In the antibacterial assays, all isolates exhibited potent activity against Escherichia coli EMBLC-1, with MIC values ranging from 0.5 to 32 µg/mL, while 7ß-hydroxy CAF-603 (7) strongly inhibited Micrococcus luteus QDIO-3 (MIC = 0.5 µg/mL). Structure-activity relationships of these compounds were discussed. The results from this study demonstrate that the endophytic fungus T. virens QA-8 from the planted medicinal herb A. argyi is a rich source of antibacterial carotane sesquiterpenes, and some of them might be interesting for further study to be developed as novel antibacterial agents.

1-(4-Fluoro-phen-yl)-3-hydr-oxy-3-phenyl-prop-2-en-1-one.

In the crystal structure the title compound, C(15)H(11)FO(2), the molecule exists in the enol form. It is stabilized by an intra-molecular O-H⋯O hydrogen bond, in which the donor O-H and acceptor H⋯O distances are almost equal. The dihedral angle between the two benzene rings is 22.30 (4)°.

Synthesis, photophysical and solvatochromic properties of diacetoxyboron complexes with curcumin derivatives.

Five novel diacetoxyboron complexes of ß-diketones incorporated curcumin moiety were designed and synthesized. Their photophysical behaviors were investigated by UV-vis absorption and fluorescence spectroscopy in different solvents and solid state. It was observed that their fluorescence spectra yielded a blue to yellow-green emission in solution and emitted a yellow to red emission in solid state. Especially, the complex 3b displayed the strongest emission and the highest quantum efficiency (Φu = 0.98) in toluene among these complexes. The CIE coordinate of the complex 3b in solid state was positioned in an ideal red region of the chromaticity diagram. The maximal emission of these complexes exhibited a large wavelength shift and Stokes shift increased with the increase of the solvent polarity. Their dipole moment differences between the ground and excited states were also estimated by using the Lippert-Mataga equation. Meanwhile, their HOMO, LUMO energy levels and energy band gaps were calculated by cyclic voltammetry.

3-[4-(Benz-yloxy)phen-yl]-1-(2-fur-yl)-3-hydroxy-prop-2-en-1-one.

In the crystal structure of the title compound, C(20)H(16)O(4), which is in the enol form, the central benzene ring makes dihedral angles of 63.42 (9) and 5.19 (10)° with the phenyl and furan rings, respectively. There is a short strong intra-molecular O-H⋯O hydrogen bond.

Preparation and photophysical properties of thienothiophene functionalized difluoroboron bis-ß-diketonate complexes.

A series of six new thienothiophene functionalized difluoroboron bis-ß-diketonates were synthesized and characterized. Their photophysical properties were investigated by UV-vis absorption, fluorescence spectroscopy and the method of CIE chromaticity in solution and powders. The results showed that these difluoroboron complexes yielded a blue-green emission at 474-500 nm in DMF solution and emitted a green to yellow emission at 541-587 nm in powders. Especially, the complex 3c showed the stronger fluorescence intensity, much higher quantum yield (Φu = 0.89) in DMF solution and larger Stokes shifts (∆λstokes = 149 nm), longer lifetime value (τ = 3.54 ns) in powders as compared to other complexes. The CIE coordinate of the complex 3c was positioned in an ideal orange-yellow region of the chromaticity diagram. Meanwhile, their electrochemical properties were also studied by the cyclic voltammetry; the HOMO, LUMO energy levels and energy band gaps were determined from the onset oxidation and reduction potentials.

A highly sensitive fluorescent chemosensor for selective detection of zinc (II) ion based on the oxadiazole derivative.

A novel fluorescent chemosensor based on the oxadiazole, 2-(2-hydroxyphenyl)-5-(4-methoxyphenyl)-1,3,4-oxadiazole, was designed and synthesized. The interaction of the oxadiazole with different metal ions had been investigated through UV-vis absorption and fluorescence spectra in 9:1 (v/v) ethanol-water (pH=7.0) solution. The oxadiazole showed a pronounced fluorescence enhancement at 430nm upon addition of Zn2+ in aqueous solution, whereas it had no apparent interference from other metal ions. The results indicated that the oxadiazole possessed high selectivity and sensitivity to Zn2+ ion. The stoichiometric ratio between the oxadiazole and Zn2+ ion was calculated to be 2:1 by Job plot experiment, meanwhile their binding modes was confirmed by 1H NMR and mass spectrometry. Their association constant was determined to be 1.95×105M-1 and the detection limit for Zn2+ ion was 6.14×10-7mol/L.

Fluorescence quenching study of 2,6-bis(5-(4-methylphenyl)-1-H-pyrazol-3-yl)pyridine with metal ions.

A novel bispyrazole derivative 2,6-bis(5-(4-methylphenyl)-1-H-pyrazol-3-yl)pyridine was synthesized and its structure was confirmed by (1)H NMR, FTIR, MS techniques and elemental analysis. The binding interactions of BMPP with Cd(2+), Co(2+), Pb(2+) and Cu(2+) ions were investigated in MeOH-H2O solution by fluorescence quenching technique at two temperatures (25 and 35°C). Their quenching constants KSV, binding constants K, binding sites n and thermodynamic parameters (ΔH, ΔG and ΔS) were determined. The results indicated that the metal ions quenched the intrinsic fluorescence of the bispyrazole by forming the bispyrazole-metal complexes and their quenching process was a static quenching mechanism. In addition, the process of interaction was spontaneous and mainly ΔS-driven.

Synthesis and spectroscopic properties of some new difluoroboron bis-ß-diketonate derivatives.

Six new bis-ß-diketones (RCOCH2CO-C7H7N-COCH2COR) were synthesized from 3,5-diacetyl-2,6-dimethylpyridine via Claisen condensation with the corresponding esters, and then reacted with boron trifluoride etherate to afford difluoroboron bis-ß-diketonate derivatives. Their spectroscopic properties were investigated by UV-vis, FTIR, (1)H NMR and fluorescence spectroscopic techniques. It was found that these boron complexes exhibited violet or blue fluorescence emission at 422-445nm and possessed high extinction coefficients. The results indicate that the extending π-conjugation can increase the fluorescence intensity and quantum yield for these boron complexes. Especially, the compound 2b displayed the stronger fluorescence intensity and the highest fluorescence quantum yield (Φu=0.94) in these boron compounds. However, compounds 2c and 2d had the lower fluorescence intensity and quantum yield as a result of the heavy atom effect of the chlorine atom in the molecules.

Synthesis, characterization and fluorescence properties of boron difluoride pyridyl-ß-diketonate derivatives.

Five pyridyl-ß-diketones were synthesized by Claisen condensation of ethyl nicotinate with various aryl methyl ketones in benzene in the presence of sodium amide as the base, and then reacted with boron trifluoride diethyl etherate in dichloromethane to afford some new boron difluoride pyridyl-ß-diketonate derivatives. The compounds obtained were characterized using FTIR, (1)H NMR, elemental analysis and mass spectrometry. Their optical properties were studied in DMF by UV-vis absorption and fluorescence spectroscopy. The results showed that these boron complexes exhibited intense fluorescence in the blue-green region (420-490 nm) under UV radiation with a relatively high quantum yield. Especially, compounds 4b and 5b displayed much higher quantum yield as compared to compounds 1b, 2b and 3b.