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Abstract In this paper, brilliant cresyl blue (BCB) was selected as a sonosensitizer. The sonodynamic damage to human serum albumin (HSA) in the presence of BCB and the mechanism were studied by means of fluorescence and absorption spectra. Firstly, BCB could quench the intrinsic fluorescence of HSA obviously and the quenching mechanism was static quenching due to the formation of HSA-BCB complex. The results of the displacement experiments and the molecular modeling suggested that the binding site of BCB on HSA was site I, and hydrophobic forces and hydrogen bonds played major roles in the interaction between HSA and BCB. Secondly, the damage of HSA induced by the combined effects of ultrasonic irradiation and BCB was more efficient than that only BCB or ultrasound irradiation, which confirmed that BCB had sonodynamic activity. The damage degree of HSA was positively correlated with reactive oxygen species (ROS) produced in the system, which indicated that ultrasound could activate BCB to produce ROS, and the kinds of ROS produced by the combined effects of ultrasonic irradiation and BCB were mainly hydroxyl free radical, singlet oxygen and superoxide anion radical. [ABSTRACT FROM AUTHOR]

The sonodynamic damage to protein in the presence of methylene blue (MB) and the various influencing factors including ultrasonic irradiation time and MB concentration on the damage of protein were studied by fluorescence and absorption spectra. In addition, the mechanisms of the synergistic effects of ultrasound and MB were studied by oxidation–extraction photometry with several reactive oxygen species (ROS) scavengers. The results indicated that the damage of protein induced by the synergistic effects of ultrasound and MB were more serious than those that ultrasound or MB alone was applied. The damage of protein could be mainly due to the generation of ROS. The damage degree of protein increased with the increase of ultrasonic irradiation time and MB concentration because of the increased quantities of ROS generation. Both 1 O 2 and OH were the important mediators of the ultrasound-inducing protein damage in the presence of MB. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the bovine serum albumin (BSA) was selected as a target molecule, the sonodynamic damage to protein in the presence of promethazine hydrochloride (PMT) and its mechanism were studied by the means of absorption, fluorescence and circular dichroism (CD) spectra. The results of hyperchromic effect of absorption spectra and quenching of intrinsic fluorescence spectra indicate that the ultrasound-induced BSA molecules damage is enhanced by PMT. The damage degree of BSA molecules increases with the increase of ultrasonic irradiation time and PMT concentration. The results of synchronous fluorescence, three-dimensional fluorescence and CD spectra confirmed that the synergistic effects of ultrasound and PMT induced the damage of BSA molecules. The results of oxidation–extraction photometry with several reactive oxygen species (ROS) scavengers indicate that the damage of BSA molecules could be mainly due to the generation of ROS and both 1O2 and e important mediators of the ultrasound-induced BSA molecules damage in the presence of PMT. [Copyright &y& Elsevier]