Electrochemical and spectroscopic studies of the interaction of (+)-epicatechin with bovine serum albumin

A novel anion replaced gemini surfactant: Investigation on the primary interaction between gemini surfactant and BSA

Gemini surfactants (GS) could serve as the drug carrier agents for the delivery of macromolecules due to the excellent properties and tuneable structures. Little attention has been paid to the impact of counterion change on GS and the interaction between GS and protein. In this work, ibuprofen (Ibu) replaced quaternary ammonium ion GS (GS-Ibu) with the hydrophobic chain length of 8, 10, 12, 14 and 16 carbon atoms were prepared for the first-time using extraction technology. The prepared GS-Ibu has stronger electrostatic interaction compared to traditional gemini surfactants with bromide anions (GS-Br). GS were further incubated with the model macromolecule, bovine serum albumin (BSA), to form BSA/GS complexes. The colloid stability of BSA could be affected by the concentration of GS, the length of hydrophobic chain and the type of anion. GS-Ibu exhibited better ability to prevent BSA from aggregating based the result of PAGE test. The molecular level change of BSA after the introduction of GS was first reflected by UV-Visible absorption spectrum. CD spectrum results further revealed that the primary interaction leading to the change in the secondary structure of BSA is electrostatic interaction. Molecular docking and molecular dynamic simulations confirmed the presence of hydrophobic and electrostatic interaction between BSA and GS. In conclusion, the anion replaced GS could be a promising strategy to stabilize the proteins.

Green Synthesis of Silver Nanoparticles with Roasted Green Tea: Applications in Alginate-Gelatin Hydrogels for Bone Regeneration

The incorporation of silver nanoparticles (AgNPs) into alginate-gelatin (Alg-Gel) hydrogels can enhance the properties of these materials for bone regeneration applications, due to the antimicrobial properties of AgNPs and non-cytotoxic concentrations, osteoinductive properties, and regulation of stem cell proliferation and differentiation. Here, the hydrogel formulation included 2% (w/v) sodium alginate, 4 µg/mL AgNPs, and 2.5% (w/v) gelatin. AgNPs were synthesized using a 2% (w/v) aqueous extract of roasted green tea with silver nitrate. The aqueous extract of roasted green tea for AgNP synthesis was characterized using HPLC and UHPLC-ESI-QTOF-MS/MS, and antioxidant capacity was measured in Trolox equivalents (TE) from 4 to 20 nmol/well concentrations. Stem cells from human exfoliated deciduous tooth cells were used for differentiation assays including positive (SHEDs/hydrogel with AgNPs) and negative controls (hydrogel without AgNPs). FTIR was used for hydrogel chemical characterization. Statistical analysis (p < 0.05, ANOVA) confirmed significant findings. Roasted green tea extract contained caffeine (most abundant), (-)-Gallocatechin, gallic acid, and various catechins. XRD analysis revealed FCC structure, TEM showed quasispheroidal AgNPs (19.85 ± 3 nm), and UV-Vis indicated a plasmon surface of 418 nm. This integration of nanotechnology and biomaterials shows promise for addressing bone tissue loss in clinical and surgical settings.

Visible-light driven regioselective synthesis, characterization and binding studies of 2-aroyl-3-methyl-6,7-dihydro-5H-thiazolo[3,2-a]pyrimidines with DNA and BSA using biophysical and computational techniques

In recent times, fused azaheterocycles emerged as impressive therapeutic agents. Binding studies of such azaheterocycles with biomolecules is an important subject for pharmaceutical and biochemical studies aiming at the design and development of new drugs. Fused heterocyclic scaffolds, such as thiazolopyrmidines have long been used in the pharmaceutical industry for the treatment of various diseases. In this study, we have accomplished a regioselective synthesis of 2-aroyl-3-methyl-6,7-dihydro-5H-thiazolo[3,2-a]pyrimidines by the reaction of tetrahydropyrimidine-2(H)-thione with α-bromo-1,3-diketones, generated in situ from 1,3-diketones and NBS, using visible light as an inexpensive, green and renewable energy source under mild reaction conditions with wide-ranging substrate scope. The regioisomer was characterized unambiguously by 2D-NMR [1H-13C] HMBC and [1H-13C] HMQC spectroscopy. In silico toxicity data analysis showed the low toxicity risks of the synthesized compounds. Computational molecular docking studies were carried out to examine the interaction of thiazolo[3,2-a]pyrimidines with calf-thymus DNA (ct-DNA) and Bovine Serum Albumin (BSA). Moreover, different spectroscopic approaches viz. steady-state fluorescence, competitive displacement assay, UV-visible and circular dichroism (CD) along with viscosity measurements were employed to investigate the binding mechanisms of thiazolo[3,2-a]pyrimidines with DNA and BSA. The results thus obtained revealed that thiazolo[3,2-a]pyrimidines offer groove bindings with DNA and showed moderate bindings with BSA.