Bing-Mi Liu

The influence of ultrasound on the fluoroquinolones antibacterial activity

In this work, the antibacterial effect of fluoroquinolones (FQs) upon Escherichia coli (E.coli) was measured with and without application of 40 kHz ultrasound (US) stimulation. The research results demonstrated that simultaneous application of 40 kHz US apparently enhanced the antibacterial effectiveness of FQs. That is, the synergistic effect was observed and the bacterial viability was reduced when FQs and US were combined. In addition, various influencing factors, such as FQs drug concentration, US irradiation time and solution temperature, on the inhibition of E.coli were also investigated. The antibacterial activity was enhanced apparently with increasing of FQs drug concentration, US irradiation time and solution temperature. Furthermore, we discussed preliminarily the mechanism of US enhanced antibacterial activity. Results show that US can activate FQs to produce reactive oxygen species (ROS) indeed, which are mainly determined as superoxide radical anion (·O(2)(-)) and hydroxyl radical (·OH).

Spectrometric Studies on the Sonodynamic Damage of Protein in the Presence of Levofloxacin

Taking bovine serum albumin (BSA) as typical molecules, the sonodynamic damage of protein in the presence of Levofloxacin (LVFX) and its mechanism were studied by fluorescence and UV-vis spectra. Various influencing factors such as ultrasonic irradiation time, pH value, ionic strength and solution temperature on the damage of BSA were also discussed. The results showed that ultrasound can enhance the damage of LVFX on BSA. The damage degree of BSA was aggravated with the increase of ultrasonic irradiation time, solution temperature and ionic strength, whereas decreased with the increase of solution pH value. Furthermore, the reactive oxygen species (ROS) in reaction system were studied by oxidation and extraction photometry. Experimental results showed that the amounts of superoxide anion radical (·O2ˉ) and hydroxyl radical (·OH) were significantly more than that of singlet oxygen (1O2) in the presence of LVFX under ultrasonic irradiation.

The increased binding affinity of curcumin with human serum albumin in the presence of rutin and baicalin: A potential for drug delivery system

The impacts of rutin and baicalin on the interaction of curcumin (CU) with human serum albumin (HSA) were investigated by fluorescence and circular dichroism (CD) spectroscopies under imitated physiological conditions. The results showed that the fluorescence quenching of HSA by CU was a simultaneous static and dynamic quenching process, irrespective of the presence or absence of flavonoids. The binding constants between CU and HSA in the absence and presence of rutin and baicalin were 2.268×10(5)M(-1), 3.062×10(5)M(-1), and 3.271×10(5)M(-1), indicating that the binding affinity was increased in the case of two flavonoids. Furthermore, the binding distance determined according to Försters theory was decreased in the presence of flavonoids. Combined with the fact that flavonoids and CU have the same binding site (site I), it can be concluded that they may simultaneously bind in different regions in site I, and formed a ternary complex of flavonoid-HSA-CU. Meanwhile, the results of fluorescence quenching, CD and three-dimensional fluorescence spectra revealed that flavonoids further strengthened the microenvironmental and conformational changes of HSA induced by CU binding. Therefore, it is possible to develop a novel complex involving CU, flavonoid and HSA for CU delivery. The work may provide some valuable information in terms of improving the poor bioavailabiliy of CU.

Syntheses, structural determination, and binding studies of nine-coordinate mononuclear complexes (EnH2)3[EuIII(Etha)]2 · 11H2O and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O

Two novel ethylenediaminium salt of europium complexes with aminopolycarboxylic acid ligands, (EnH2)3[EuIII(Ttha)]2 · 11H2O (I) (En is ethylenediamine, H6Ttha is triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid) and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O (II) (H4Egta is ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) complexes were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction techniques. Both of the two complexes adopt nine-coordinate structures with the pseudo-monocapped square antiprism and crystallize in the monoclinic crystal system with the P21/n space group. The crystal data for complex I are as follows: a = 17.8262(8), b = 19.3137(5), c = 20.6233(8) Å, β = 111.301(2)°, V = 6615.3(4) Å3, Z = 8, ρc = 1.677 mg/m3, μ = 1.981 mm−1, F(000) = 3432, R = 0.0308, and wR = 0.0737 for 43622 observed reflections with I ≥ 2σ(I). The crystal data for complex II are as follows: a = 12.952(3), b = 12.618(2), c = 14.809(3) Å, β = 105.695(2)°, V = 2330.0(8) Å3, Z = 4, ρc = 1.800 mg/m3, μ = 2.765 mm−1, F(000) = 1276, R = 0.0297, and wR = 0.0638 for 18416 observed reflections with I ≥ 2σ(I). One remarkable feature of the two complexes is that the protonated [EnH22+] cations conjugating to [EuIII(Ttha)]26− and [EuIII(Egta)(H2O)]22− complex anions are reviewed, respectively, which open the path for the EuIII complexes conjugating with other various biomolecules.

Syntheses of the eight-coordinate NH4[ErIII(Cydta)(H2O)2] · 4.5H2O and (NH4)2[Er2III (Pdta)2(H2O)2] · 2H2O complexes and their structural investigation

AbstractIn this work, the title complexes, NH4[ErIII(Cydta)(H2O)2] · 4.5H2O (I) (H4Cydta = trans-1,2-cyclo-hexanediamine-N,N,N′,N′-tetraacetic acid) and (NH4)2[Er2III(Pdta)2(H2O)2] · 2H2O (II) (H4Pdta= propylene-diamine-N,N,N′,N′-tetraacetic acid), were prepared, respectively, and their composition and structures were determined by elemental analyses and single-crystal X-ray diffraction techniques. Complex I selects a mononu-clear structure with pseudosquare antiprismatic geometry crystallized in the triclinic crystal system with space group

Structural determination of new eight-coordinate NH4[EuIII(Cydta)(H2O)2]·4.5H2O and K2[Eu2III(pdta)2(H2O)2]·6H2O complexes

P\bar 1

Mononuclear eight-coordinate (NH4)3[YIII(Nta)2] and one-dimensional unlimited zigzag type nine-coordinate {K[YIII(Egta) · 4H2O}n complexes: Syntheses and structural determination

and the central Er3+ ion is eight-coordinated by the hexadentate Cydta ligand and two water molecules. The crystal data are as follows: a = 8.568(3), b = 10.024(3), c = 14.377(4) Å, α = 88.404(4)°, β = 75.411(4)°, γ = 88.332(4)°, V = 1194.2(6) Å3, Z = 1, ρc = 1.793 g/cm3, μ = 3.586 mm−1, F(000) = 648, R = 0.0257, and wR = 0.0667 for 4169 observed reflections with I ≥ 2σ(I). Complex II is eight-coordinated as well, which selects a binuclear structure with two pseudosquare antiprismatic geometry and crystallizes in the monoclinic crystal system with space group P21/n. The central Er3+ ion is coordinated by two nitrogens and four oxygens from one hexadentate Pdta ligand. Besides, two oxygens come from one carboxylic group of the neighboring Pdta ligand and one water molecule, respectively. The crystal data are as follows: a = 12.7576(8), b = 9.3151(6), c = 14.3278(9) Å, β = 96.1380(10)°, V = 1692.93(19) Å3, Z = 4, ρc = 2.054 g/cm3, μ = 5.015 mm−1, F(000) = 1028, R= 0.0228, and wR = 0.0534 for 2984 observed reflections with I ≥ 2σ(I).

Protein damage and reactive oxygen species generation induced by the synergistic effects of ultrasound and methylene blue.

In recent years, sonodynamic activities of many drugs have attracted more and more attention of researchers. The correlative study will promote the development of sonodynamic therapy (SDT) in anti-tumor treatment. In this work, bovine serum albumin (BSA) was used as a protein model to investigate the intensifying effects of ciprofloxacin (CPFX) ultrasonically induced protein damage by UV-vis and fluorescence spectra. Meanwhile, the conformation of BSA is changed upon the addition of CPFX and metal ions under ultrasound (US) so that the damaging site of BSA is considered. Various influencing factors, such as US irradiation time, metal ions, solution temperature and ionic strength, on the ultrasonically induced BSA damage are discussed. It was showed that CPFX could enhance ultrasonically induced BSA damage. The damage degree of BSA was aggravated with the increasing of US irradiation time, solution temperature, ionic strength as well as the addition of metal ions. Furthermore, the reactive oxygen species (ROS) in reaction system were detected by oxidation-extraction photometry (OEP). Experimental results also showed that US could activate CPFX to produce ROS, which were mainly determined as superoxide radical anion (.O2-) and hydroxyl radical (.OH).