thymus DNA (ctDNA) was assumed by the change of UV-vis spectroscopy, fluorescence and resonance light-scattering (RLS). The changed absorption spectral properties of TEPyP titrated with ctDNA were observed from red shifted (λ=14nm) and a large hypochromicity (42%). In fluorescence spectra, λex,max of TEPyP shifted to longer wavelength (λ=13nm) and a decrease around 50% of the emission intensity were shown. The signal of resonance light-scattering was enhanced by nucleic acid. The study on the inclusion interaction of TEPyP with β-cyclodextrin (β-CD) and its derivatives including hydroxypropyl- -cyclodextrin (HP- -CD), sulfobutylether-β-cyclodextrin (SBE-β-CD) shown that the formation constants for β-CD, HP-β-CD and SBE-β-CD with TEPyP were 550, 1.1×104 and 2.0×105M−1, respectively, with 1:1 stoichiometry. The conformation confirmed by 1HNMR technique is that the alkyl and pyrrole cyclic moiety entered into the cavity of cyclodextrins. Comparative study on the interaction of TEPyP with ctDNA was further carried out in the presence of β-CD, HP-β-CD, and SBE- -CD. The significant decrease of the binding constants and binding numbers were observed and the interaction of DNA-bound porphyrin has been inhibited. Moreover, the stronger inclusion ability of TEPyP and CDs, the bigger influence on the interaction of TEPyP with DNA, which was due to the fact that TEPyP enter into the cavity of CDs. It may influence binding affinity of porphyrin to DNA and weaken the static electronic forces in the outside self-stacking. Typically, the negative SBE-β-CD hampers directly the binding of the negative phosphate groups of the DNA backbone and the positive TEPyP.

The ability of b-cyclodextrin (b-CD), hydroxypropyl-b-cyclodextrin (HP-b-CD), and carboxymethyl-b-cyclodextrin (CM-b-CD) to break the aggregate of the methylene blue (MB) and to form 1:1 inclusion complexes has been studied by absorption and fluorescence spectroscopy. Experimental conditions including concentrations of various cyclodextrins (b-CD, HP-b-CD and CM-b-CD) and media acidity were investigated for the inclusion formation in detail. The formation constants are calculated by using steady-state fluorimetry, from which the inclusion capacity of different cyclodextrins (CDs) is compared. The results suggest that the charged b-cyclodextrin (CM-b-CD) is more suitable for inclusion of the cationic dye MB than the neutral b-cyclodextrins (b-CD, HP-b-CD) at pH/5. A mechanism is proposed which is consistent with the stronger binding of MB with CM-b-CD compared with the other CDs at pH/5.

A gas chromatography-mass spectrometric (GC-MS) method for the determination of total isothiocyanates (ITCs) has been developed based on the quantification of the cyclocondensation product, 1,3-benzodithiole-2-thione, between ITCs and 1,2-benzenedithiol. It was the first analytical application to be applied to the analysis of Chinese medicinal herbs including Laifuzi, Baijiezi, Tinglizi and Hancai, and seeds of commonly consumed vegetables.Aconsiderable variation in ITC contentswas observed. The highest concentrations of total ITCs were found to be 20.3mol/g in Laifuzi and 12.6 mol/g in seeds of Chinese kale. The method demonstrates the usefulness of the cyclocondensation of ITCs with 1,2-benzenedithiol reagent for quantifying total ITC contents in Chinese medicinal herbs regardless of the types of ITC. The linear dynamic range covered from 0.12 to 200 MITC. The limit of detection (3Sb)was 35nMand the corresponding absolute detection limitwas 35 fmol. The proposedGC-MStechnique provides a reliable, unambiguous, reproducible, and efficient method for determining total ITCs of various samples.

The inclusion interaction of the complexes between Vitamin K3 (VK3) and b-cyclodextrin (b-CD), hydroxypropyl-bcyclodextrin (HP-b-CD) and sulfobutylether-b-cyclodextrin (SBE-b-CD) were studied by using steady-state fluorescence measurements. The various factors affecting the inclusion process were examined in detail. The formation constants and inclusion stoichiometry for VK3/CDs were determined. The results showed that the inclusion ability of b-CD and its derivatives was the order: SBE-b-CD/HP-b-CD /b-CD. The related inclusion mechanism is proposed to explain the inclusion process. A method of determining VK3 was established with the linear range was 2.5/10 6/5.0/10 4M, and was used to determine the VK3 tablets. The recoveries were in the range of 97.52/103.5%. The results were satisfactory.

DNA assembling to neutral red (NR) and cyclodextrins (CDs)-NR inclusion complex has been investigated by means of absorption, fluorescence and resonance light scattering (RLS). Depending on the molar ratio R of NR:DNA, the binding of NR with DNA involved in two processes at pH 7.50 and ionic strength 0.0045. The first process occurs in R > 2:5, where the neutral form of R was predominant and enhanced RLS was observed, indicating the aggregation of NR neutral form molecules on the molecular surface of DNA. The second process occurs in R < 2:5, where an absorption band at 540nm and a fluorescent excitation and emission band at 550 and 607 nm respectively provided compelling evidence that the binding of NR to DNA leaded to extensive NR protonation even at pH 7.50, and that a protonated NR (the acidic form of NR) can form DNA adducts with a binding mode different from that of the unprotonated form (the neutral form of NR). The results were also illustrated by the CDs-NR supramolecular system. The experimental data showed that CDs including b-CD, hydroxypropyl-b-CD (HP-b-CD) and sulfobutyletherb-CD (SBE-b-CD) superior to include the neutral form of NR, in addition, the inclusion complex decomposed when it bound to DNA. Thus, the decomposed NR was also protonated to form DNA adducts with intercalative mode. In fact, CDs played a role to carry guest molecule to intercalate DNA. A related mechanism is proposed.