Design,synthesis and biological evaluation of fluorescent derivatives of ursolic acid in living cells

Ursolic acid(UA)is a naturally occurring ursane triterpenoid,which exhibits a wide range of unique biological activities.To clarify its mechanism of action(MOA),a series of fluorescent derivatives of UA(5a-c)were designed and synthesized by conjugation with 7-nitrobenzo-2-oxa-1,3-diazole(NBD)fluorophore.Among them,5c exhibited similar anti-proliferative activity with UA against HCT116 cells(half maximal inhibitory concentration(IC_(50))=9.21±0.50μmol/L).Cell imaging experiment indicated that 5c was rapidly taken up in HCT116 cells in a dose and time-dependent manner.Then,5c was found to localize in endoplasmic reticulum(ER),lysosomes,and mitochondria,but not in nucleus of HCT116 cells by confocal microscopy studies.Preliminary MOA proved that UA induced autophagy with a unique intracellular distribution mechanism involving ER and lysosome.In all,our work provides new clues for revealing the molecular mechanism of UA as an antitumor agent.

One Novel 2D Co(Ⅱ) Polymer with 1,2,3-Triazole Derivative: Crystal Structure, Fluorescence and Hirshfeld Surface Analysis

One new polymer [Co（L）（H2O）2]n（1） was synthesized by 4-（ethoxycarbonyl）-5-methyl-1H-1,2,3-triazole-1-carboxylic acid（Emtc） under the in situ solvent thermal reaction（H2L = 1-（carboxymethyl）-5-methyl-1H-1,2,3-triazole-4-carboxylic acid）. The title complex performs a wave-like 2D framework and the ligand H2L demonstrates the coordination mode as μ4-η-2：η-1η-1：η-1. The crystal structure has been established by single-crystal X-ray diffraction, and characterized by FT-IR. Fluorescent property was investigated in this work. Hirshfeld surface analysis has also been carried out on 1, and obvious main intermolecular interactions are observed.

Synthesis, Crystal Structure and Two-photon Absorption Properties of 4′-(N,N-di(4-hydroxymethyl phenyl) amino)phenyl-2,2′:6′,2''-terpyridine

A novel donor-acceptor （D-A） triphenylamino terpyridine derivative L was facilely synthesized and fully characterized, and its single crystals were obtained and determined by X-ray diffraction analysis. It crystallizes in triclinic, space group P/ with a = 11.760（5）, b =12.516（5）, c = 12.850（5） A, α = 67.141（5）, β= 65.284（5）, γ = 75.876（5）°, Mr = 621.54, F= 1575.6（11） A3, Z= 2, Dc = 1.310 g/cm3,μ = 0.245 mm-1, F（000） = 648, the final R = 0.0671 and wR = 0.1869 for 11328 observed reflections with 1〉 2σ（I）. Linear and nonlinear optical properties of terpyridine derivative L were systematically investigated. The maximum two-photon cross-section of L was 382.5 GM （Goeppert-Mayer）, measured by two-photon excited fluorescence （TPEF） method. This result demonstrates that the increase of intramolecular charge transfer （ICT） leads to enhanced two-photon absorption （2PA）, which could be achieved by introducing additional electron-donor groups to the molecular framework.

Study on State of Terbium Ion in Liposome by One order Derivative Fluorescence Quenching Method

The state of Tb3+ is investigated in liposome. When the concentration of PC is below CMC (critical micell concentration), most of Tb3+ is associated with PC, the binding constant is about 3.35×103 L/mol. When the concentration of PC is beyond CMC, most of Tb3+ is dimerized, the dimerization constant is about 3.92×104L/mol. In PC?CH?H2O system, the binding constant of Tb3+?CH complex 2.93×104L/mol is obtained.

STUDIES ON FLUORESCENCE SPECTRA OF SAMARIUM EUROPIUM TERBIUM AND DYSPROSIUM WITH BENZOYL UREA DERIVATIVES AND PHENANTHROLINE

Rare earth chelates of benzoyl urea derivatives were prepared in ethanol and fluorescence spectra of these chelates were studied in detail. A composition of [RE(BU)_3Phen] (NO_3)_3 was obtained. Correlation between chemical properties of ligands, chelates and spectroscopy was discussed. Intramolecular energy transfer in rare earth chelates was explained.

Synthesis and Photophysical Properties of Novel Rod-shaped and Star Shaped Fluorescent Phosphane Derivatives

1 Results Over the past few years significant research has been directed toward the development of organic materials for potential application in molecular photonic devices[1] and the development of sensors[2].Interest in these materials is primarily due to the infinite numbers of possible molecular structures with the desired properties,by virtue of the tremendous capabilities of organic synthesis.For the development of a new fluorescent molecular sensor consisting of a recognition moiety linked to a f...

Probing the redox process of p-benzoquinone in dimethyl sulphoxide by using fluorescence spectroelectrochemistry

Quinones are common organic compounds frequently used as model dissolved organic matters in water, and their redox properties are usually characterized by either electrochemical or spectroscopic methods separately. In this work, electrochemical methodology was combined with two fluorescence spectroelectrochemical techniques, cyclic voltafluorescence spectrometry （CVF） and derivative cyclic voltafluorescence spectrometry （DCVF）, to determine the electrochemical properties of p-benzoQuinone in dimethvl sulfoxide, an aprotic solution. The CVF results show that the electrochemical reduction ofp-benzoquinone resulted in the formation of radical anion and dianion, which exhibited a lower fluorescence intensity and red-shift of the emission spectra compared to that of p-benzoauinone. The fluorescence intensity was found to vary along with the electrochemical oxidation and reduction ofp-benzoquinone. The CVF and DCVF results were in good consistence. Thus, the combined method offers a powerful tool to investigate the electrochemical process of p-benzoquinone and other natural organic compounds.

Cationic conjugated polymers as signal reporter for label-free assay based on targets-mediated aggregation of perylene diimide quencher

Herein, we reported a new label-free and fluorescence turn-on biosensor based on cationic conjugated poly（9,9-bis（6＇-N,N,N-trimethylammonium）hexyl）fluorine phenylene）（PFP） and perylene diimide derivatives（PDI）. Cationic PFP, single-stranded nucleic acid and PDI were used as signal reporter, probe and fluorescence quencher, respectively. In the presence of nucleic acids, they form complexes with PFP and PDI through strong electrostatic attraction interactions, resulting in PDI aggregating on nucleic acids and fluorescence of PFP being quenched. When nucleic acids are hydrolyzed by enzymes or their conformation is changed via recognizing targets, the effective aggregation of PDI is disrupted and the quenching ability is decreased. Thus the fluorescence of PFP recovers significantly. By taking advantage of the mechanism, we construct a new biosensor for endonuclease and small molecules detection. Here, S1 nuclease and bisphenol A are used as model systems. The detection limit of the SI nuclease and BPA are1.0×10^-6U/mL and 0.05 ng/mL, respectively. Our method is sensitive, cost-effective and simple, and provides a new platform for bioanalysis.

Communication Chain-foldability effect on coaggregation Evidence derived from time-resolved fluorescence spectroscopy

Very recently,we have proposed that all culprit molecules of arteriosclerosis mightpossess a common and measurable inherent property,namely,a coaggregating ten-dency.Extensive kinetic measurements of these tendencies in terms of △CAgC valueshave led to a new and surprising observation,i.e.,the cholesteryl ester with a longsaturated 18-carbon chain(CE-18)actually has a much smaller tendency towardcoaggregation than that of the ester with a“short”8-carbon chain(CE-8).Thisstate of affairs has been coined as the“chain-foldability effect”,i.e.,the 18-carbon

Electrostatically stabilized aggregate(ESAg)——Ⅲ.Evidence derived from the coaggregating behavior of fluorescence probes(FP)with ionic surfactants

Hydr hobie一lipophilic interactions(HLI)will start to bri about the formationof simple aggregates(Ag,s)and eoa egates(CoAg,s)from neutral organie moleeuleswhich possess at least onefl ble chain with more than seven eHZ grou ,1,2 at theeritieala egate eoncentration