The effect of inclusion complex formation on the fluorescence properties of berberine, a clinically important natural alkaloid, was studied using cucurbit [7]uril as macrocyclic host compound. The formation of a very stable 1:1 inclusion complex led to about 500-fold fluorescence intensity enhancement, which facilitated the detection of berberine even below nanomolar concentration. Addition of NaCl caused a significant change in the association constant and the fluorescence characteristics of the complex, whereas the variation of the anion had a small effect. 1-Alkyl-3-methylimidazolium type ionic liquids altered the fluorescent properties of the berberine-cucurbit[7]uril complex much more efficiently than did NaCl. Time-resolved fluorescence studies showed ternary complex formation. Because berberine fluorescence is insensitive to pH and increases substantially upon inclusion in cucurbit[7]uril, the reversible self-assembly of this host-guest pair may find analytical application in enzyme assays.

Copper-containing enzymes perform fundamental functions by activating dioxygen (O2) and therefore allowing chemical energy-transfer for aerobic metabolism. The copper-dependence of O2 transport, metabolism and production of signalling molecules are supported by molecular systems that regulate and preserve tightly-bound static and weakly-bound dynamic cellular copper pools. Disruption of the reducing intracellular environment, characterized by glutathione shortage and ambient Cu(II) abundance drives oxidative stress and interferes with the bidirectional, copper-dependent communication between neurons and astrocytes, eventually leading to various brain disease forms. A deeper understanding of of the regulatory effects of copper on neuro-glia coupling via polyamine metabolism may reveal novel copper signalling functions and new directions for therapeutic intervention in brain disorders associated with aberrant copper metabolism.

The encapsulation of 4',6-diamidino-2-phenylindole (DAPI) in the cucurbit[7]uril (CB7) cavity was studied by absorption, fluorescence, and NMR spectroscopic methods in aqueous solution. The profound change in the fluorescence characteristics was attributed to the formation of a very stable 1:1 inclusion complex. Three independent methods provided (1.1+/-0.1)x10(7) M(-1) value for the binding constant. DAPI proved to be an excellent fluorescent probe for the investigation of the competitive binding of ionic liquids, surfactants, and biologically important compounds to CB7. The equilibrium constant of 1-alkyl-3-methylimidazolium inclusion was found to go through a maximum as the aliphatic chain length was increased, reaching the highest value for the hexyl derivative. The variation of the anion had a small effect. Among cationic surfactants containing a dodecyl tail, the stability of CB7 complex diminished with the growing hydrophobicity of the head group.

The distribution of fatty acids in a triacylglycerol is of great importance from nutritional, biochemical, quality and technological points of view. The ratio of triacylglycerol positional isomers containing two linoleic acid (18:2) and one oleic acid (18:1) moieties--namely, 1(3),2-dilinoleoyl-3(1)-oleoyl glycerol (LLO) and 1,3-dilinoleoyl-2-oleoyl glycerol (LOL)--were quantified in grape seed, olive, pumpkin seed, soybean, sunflower and wheat germ oils by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) in selected ion monitoring (SIM) mode. Relative LOL contents (LOL/(LLO+LOL)) of the oils were calculated from the mass abundances of the [LL]+ and [LO]+ diacylglycerol fragment ions ([M+H-RCOOH]+) using a calibration curve. The calibration curve of the relative diacylglycerol mass abundances was measured in SIM mode. The relative LOL contents were found to be relatively consistent for each oil variety. The relative LOL content in grape seed, sunflower, pumpkin seed, soybean and wheat germ oils accounted for 44.2 +/- 2.6, 26.8 +/- 3.2, 16.7 +/- 4.6, 15.9 +/- 2.9 and 13.9 +/- 4.3%, respectively. Only olive oils contained practically 100% of the LLO isomer. These results indicate that the unsaturated fatty acids such as linoleic and oleic acids have 'non-random' distribution patterns in various oils.

derivatives among which , -dithiolane derivative showed higher activity than the oxathiolanes. Various , -dioxolane--ones provided significant protection against the acetochlor. "enzo[ , ]-dioxoles were ineffective while benzo [ , ]dioxin--ones were protective in safening maize. -Dichloromethyl--substituted-isoxazoles were also active safeners.Unfortunately, no publication has been reported for the other chemistry of safeners. However, no unifying structural motifs for compounds to be safeners can be predicted from these studies.

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The temperature dependence of the kinetics of flavopereirine inclusion in cucurbit[7]uril (CB7) was studied by a stopped-flow method in water. The substantial blue-shift of the emission band and the ∼4-fold fluorescence quantum yield enhancement upon host-guest binding permitted the monitoring of the formation and dissociation of the flavopereirine-CB7 1 : 1 complex in real time. The competitive binding of the 1-adamantylammonium cation with extremely high affinity was exploited to selectively and very accurately determine the kinetic parameters of the exit of flavopereirine from the CB7 cavity. The rate constants of the ingression into and the egression from CB7 were found to be 9.0 × 10 M s and 1.6 s at 298 K, respectively. Both processes had substantial activation enthalpy implying that a steric barrier had to be overcome in the course of the reversible encapsulation. The 31 ± 2 kJ mol activation enthalpy of the entry into CB7 was comparable to the 37 ± 2 kJ mol enthalpy change upon the dissociation of the complex.