Anti-aggregation property of thymoquinone induced by copper-nanoparticles: A biophysical approach

Renewable rosin-based bisquaternary ammonium salt with pyridyl design, synthesis and antifungal activity

In order to synthesize green, low-toxicity, and novel antifungal agents. In this study, a rosin-based bisquaternary ammonium salt (Rbs) was synthesized using rosin amine and evaluated for its antifungal activity against F. oxysporum f. sp. niveum, F. graminearum, V. mali, P. capsica and A. solani. The results show that compared to benzalkonium bromide, Rbs has stronger inhibitory activity against five types of fungi, with the best activity against V. mali (EC50 = 3.071 μg/mL), and has excellent sustained antifungal activity. In vivo tests have shown that Rbs has significant protective and therapeutic effects on apples. Using SEM, TEM, relative membrane permeability and density functional theory calculations, we found that Rbs causes organelle and cell membrane disruption, leading to leakage of cell contents and ultimately cell death. In addition, mouse toxicology showed that the toxicity of Rbs was low. These studies provide theoretical guidance for the development of subsequent fungicides.

Sunset Yellow Dye Induces Amorphous Aggregation in β-Lactoglobulin at Acidic pH: A Multi-Techniques Approach

Protein aggregation is of two types: (i) amorphous and (ii) amyloid fibril. Several extrinsic factors (temperature, pH, and small ligands) stimulate protein aggregation in vitro. In this study, we have examined the role of sunset yellow (SY) on the β-lactoglobulin (BLG) aggregation at pH 2.0. We have used spectroscopic (turbidity, Rayleigh light scattering (RLS), far-UV CD) and microscopic (transmission electron microscopy [TEM]) techniques to describe the effects of SY on BLG aggregation. Our results showed that BLG aggregation is dependent on SY concentrations. Very low concentrations (0.0–0.07 mM) of SY were unable to induce aggregation, while SY in the concentrations range of 0.1–5.0 mM induces aggregation in BLG. The kinetics of SY-stimulated aggregation is very fast and monomeric form of BLG directly converted into polymeric aggregates. The kinetics results also showed SY-induced BLG aggregation disappeared in the presence of NaCl. The far-UV CD and TEM results indicated the amorphous nature of SY-induced BLG aggregates. We believe that our results clearly suggest that SY dye effectively stimulates BLG aggregation.

Phytochemical thymoquinone prevents hemoglobin glycoxidation and protofibrils formation: A biophysical aspect

d-ribose, a reducing sugar, in diabetic hyperglycemia provokes non-enzymatic glycoxidation of hemoglobin (Hb), an abundant protein of red blood cells (RBCs). Different types of intermediates adduct formation occur during glycoxidation, such as advanced glycation end-products (AGEs) which lead to amyloid formation due to structural and conformational alterations in protein. Therefore, the study of these intermediate adducts plays a pivotal role to discern their relationship with diabetes mellitus and related disorders. Here, we investigated the interaction mechanism of d-ribose with Hb, and Hb prebound phytochemical thymoquinone (TQ). Our investigation reveals that the interaction of TQ with histidine residues of Hb interferes with the interaction of d-ribose with glycine residues at the glycation-site. Based on that, we had performed a time-based (21-days) in-vitro glycoxidation study at 37 °C to investigate the structural perturbation mechanism of Hb at different time-intervals in absence/presence of TQ. We found that prolonged glycoxidation induces amyloid formation in absence of TQ but in its presence, the process was prohibited. In summary, this study examined and characterized biophysically different intermediate-states of protein carrying glycoxidation-modification. Our findings suggested that TQ potentially affects interaction of d-ribose with Hb that prevents glycoxidation and protofibril formation, which establishes TQ as a potential therapeutic agent.

Advances in Rosin-Based Chemicals: The Latest Recipes, Applications and Future Trends

A comprehensive review of the publications about rosin-based chemicals has been compiled. Rosin, or colophony, is a natural, abundant, cheap and non-toxic raw material which can be easily modified to obtain numerous useful products, which makes it an excellent subject of innovative research, attracting growing interest in recent years. The last extensive review in this research area was published in 2008, so the current article contains the most promising, repeatable achievements in synthesis of rosin-derived chemicals, published in scientific literature from 2008 to 2018. The first part of the review includes low/medium molecule weight compounds: Especially intermediates, resins, monomers, curing agents, surfactants, medications and biocides. The second part is about macromolecules: mainly elastomers, polymers for biomedical applications, coatings, adhesives, surfactants, sorbents, organosilicons and polysaccharides. In conclusion, a critical evaluation of the publications in terms of data completeness has been carried out with an indication of the most promising directions of rosin-based chemicals development.

Rheological Behavior of Environmentally Friendly Viscoelastic Solutions Formed by a Rosin-Based Anionic Surfactant

It is of great significance to explore novel applications of renewable resources. In this study, a rosin-based anionic surfactant (abbreviated R-11-2-Na), which contains a large hydrophobic group of 30 carbon atoms, was synthesized. R-11-2-Na forms wormlike micelles in the presence of the equimolar organic salt choline chloride, endowing solutions with strong viscoelasticity. The wormlike micellar solutions were investigated using rheology, small-angle X-ray scattering, and freeze-fracture transmission electron microscopy (FF-TEM) methods at 25 °C. Due to the strong van der Waals interactions caused by the large hydrophobic group contained in R-11-2-Na, the zero-shear viscosity (η₀) of solutions showed extremely strong dependence on the concentration with an exponent of 23.4. The cross-sectional diameter of the wormlike micelles in the present system was significantly larger than that of the wormlike micelles formed by surfactants containing conventional alkyl tails. This finding may be attributed to the steric hindrance brought by the bulky and rigid dehydroabietic acid unit in the hydrophobic part. The wormlike micelles also showed high tolerance to the organic salt concentration. The present study reveals the notable qualities of rosin-based derivatives in forming complex fluids and facilitates new utilizations of forest resources.

Applications of rice protein in nanomaterials synthesis, nanocolloids of rice protein, and bioapplicability

Rice protein conjugated nanomaterials were synthesized and characterized by using anionic and cationic forms of rice protein. Both forms showed unique characteristic features when used in in situ reaction conditions for synthesizing the protein stabilized gold (Au) and silver (Ag) nanoparticles (NPs). Au NPs synthesis was highly facilitated than Ag NPs synthesis while the reverse was true when rice protein was simply used in the basic medium. Photophysical behavior clearly showed the contributions of both electrostatic and non-electrostatic interactions driving the rice protein surface adsorption on nanometallic surfaces. Rice protein conjugated NPs were easily transferred and extracted into the organic phase while the extraction process was related to the amount of protein coating. Under the controlled pH reaction conditions, rice protein - dye colored NPs were synthesized which were further characterized by the DLS and SDS Page analysis. Both rice protein conjugated Au/Ag NPs and rice protein NPs showed remarkable biocompatibility with blood cells. These NPs demonstrated their excellent ability to selectively extract protein fractions from complex biological fluid like serum. The results proposed significant applications of rice protein conjugated NPs in biological systems as well as bio-nanotechnology.

Morphological Effects of CuO Nanostructures on Fibrillation of Human Serum Albumin

The influence of different morphologies of nanostructures on amyloid fibrillation has been investigated by monitoring the fibrillation of human serum albumin (HSA) in the presence of rod-, sphere-, flower-, and star-shaped copper oxide (CuO) nanostructures. The different morphologies of CuO have been synthesized from an aqueous solution-based precipitation method using various organic acids, viz., acetic acid, citric acid, and tartaric acid. The fibrillation process of HSA has been examined using various biophysical techniques, e.g., Thioflavin T fluorescence, Congo red binding studies through UV spectroscopy, circular dichroism spectroscopy, and fluorescence microscopy. The monolayer protein coverage on the CuO nanostructures has been established through DLS studies, and the well-fitted Langmuir isotherm model has been used to interpret the differential adsorption behavior of HSA molecules on the CuO nanostructures. The nanostar-shaped CuO, by virtue of their higher specific surface area (94.45 m² g^-1), presence of high indexed facets {211} and high positive surface charge potential (+16.2 mV at pH 7.0) was found to show the highest adsorption of the HSA monomers and thus was more competent to inhibit the formation of HSA fibrils compared to the other nanostructures of CuO.

Biophysical insight into the interaction mechanism of plant derived polyphenolic compound tannic acid with homologous mammalian serum albumins

Numerous phenolic compounds have been reported in the last decade that have a good antioxidant property and interaction affinity towards mammalian serum albumins. In the present study, we have utilized mammalian serum albumins as a model protein to examine their comparative interaction property with polyphenolic compound tannic acid (TA) by using various spectroscopic and calorimetric methods We have also monitored the esterase and antioxidant activity of mammalian serum albumins in the absence and presence of TA. The obtain results recommended that the TA have a good binding affinity (∼10⁴ to 10⁶M^-1) towards mammalian serum albumins and shows double sequential binding sites, which depends on the concentration of TA that induced the conformational alteration which responsible for the thermal stability of proteins. Binding affinity, structural transition and thermodynamic parameters were calculated from spectroscopic and calorimetric method reveals that non-covalent interaction causes partial conformational alteration in the secondary structure of protein ie.; increase in α-helical content with decrease in β-sheet, random coil and other structure. Meanwhile, we have found that esterase activities of serum albumins were also stabilized against hydrolysis and shows higher antioxidant activity in the presence of TA because albumins its self have an immense antioxidant activity beside TA.