Biophysical studies on the interactions of jatrorrhizine with bovine serum albumin by spectroscopic and molecular modeling methods

A highly selective and simple fluorescent probe for salbutamol detection based on thioglycolic acid-capped CdTe quantum dots

In this paper, a highly fluorescent water-soluble CdTe quantum dots (CdTe QDs) stabilized with thioglycolic acid (TGA) were synthesized for the quantitative and selective determination of salbutamol (SAL). When ten different of 2.09 × 10^-6 mol L^-1 alpha-2 adrenoceptor agonist were added to 4.38 × 10^-4 mol L^-1CdTe QDs solution, the fluorescence signal of the CdTe QDs quenched obviously by SAL with 57.32% and 0.815% - 7.00% for other nine kinds of veterinary medicine, such as tulobuterol, fenoterol, phenylethanamine A, simatero, penbutolol, clenbuterol, ractopamine, terbutaline and clorprenaline. The result shows that the CdTe QDs is highly sensitive sensor for SAL. The quenching mechanism has been investigated by absorption spectroscopy and K_SV at different temperatures, and shew a static quenching process than dynamic quenching. Under the optimal conditions, respectively the straight line equation (F₀/F = 0.1491 × 10⁶ C + 1.3078) was found between the relative fluorescence intensity and the concentration of SAL was in the range of 6.27 × 10^-8 to 2.09 × 10^-7 mol L^-1, and the limit of detection was 4.2 × 10^-8 mol L^-1. The proposed method has been applied to the determination of SAL in pig urine samples.

Molecular Interaction of Hemorrheologic Agent, Pentoxifylline with Bovine Serum Albumin: An Approach to Investigate the Drug Protein Interaction Using multispectroscopic, Voltammetry and Molecular Modelling Techniques

The interaction between pentoxifylline (PTX) and bovine serum albumin (BSA) was studied under physiological condition by spectroscopic, voltammetry and molecular modelling techniques. The results of fluorescence studies revealed that the quenching mechanism of BSA by PTX was a static procedure. Binding constant of PTX-BSA was calculated and its value found to be 8.895 × 104 M−1, which is in close agreement with the results obtained from UV-Visible and voltammetry approach. The negative values of thermodynamic parameters (ΔG, ΔH and ΔS) indicated that van der Waals force and hydrogen bonding play major roles in the interaction of PTX with BSA. Based on Forster’s theory of non-radiation energy transfer, the binding distance (r) between the donor (BSA) and acceptor (PTX) was found to be 5.38 nm (298 K). The results of UV-Visible and circular dichroism (CD) spectroscopy showed that PTX interacts with BSA and induces conformational changes by reducing the α-helix content. The results of the UV-visible and voltammetry studies were further verified by the molecular docking method. Molecular modelling studies revealed possible residues involved in the drug-protein interaction and indicated that PTX binds to Site IIA of BSA.

Natural isoquinoline alkaloids: binding aspects to functional proteins, serum albumins, hemoglobin, and lysozyme

The putative anticancer alkaloids berberine, palmatine, jatrorrhizine, and sanguinarine are known to bind to nucleic acids. To develop them as potential drugs for therapeutic use, their binding affinity to functional proteins and mode of transport in the circulatory system need to be clearly understood. Towards this, many studies on their binding aspects to proteins have been reported and a considerable amount of data, mostly of biophysical nature, exists in the literature. The importance of these natural isoquinoline alkaloids and the recent literature on their interaction phenomena with functional proteins, serum albumins, hemoglobin, and lysozyme are presented in this review.

Detection of DNA using an “off-on” switch of a regenerating biosensor based on an electron transfer mechanism from glutathione-capped CdTe quantum dots to nile blue

A new DNA detection method, which relies on the “off-on” switch of a regenerated fluorescence biosensor based on an electron transfer mechanism from glutathione (GSH)-capped CdTe quantum dots (QDs) to nile blue (NB), is proposed.