The affinity of histamine to serum albumin: Capillary electrophoresis-frontal analysis and in-silico molecular docking approaches

Histamine is a biogenic amine found in various body tissues and responsible for many critical vital activities. It is also responsible for allergic reactions in the body. Ingestion of foods containing high amounts of histamine can cause fatal allergic reactions. Albumin in plasma controls drugs and free concentrations of bioactive constituents taken to the body with food. Hence, this study aimed to characterise the interactions of histamine with bovine serum albumin. Capillary electrophoresis in the frontal analysis mode was employed in this study as a practical approach for assessing histamine-bovine serum albumin affinity. The plateau-shaped free histamine peak was well separated from the bovine serum albumin (BSA)-histamine complex peak. The free histamine concentration was obtained by following the height of the free histamine peak. Whereas the bound histamine concentrations were obtained by calculating the difference between the height of total and free histamine peaks. Histamine bound to BSA at one independent site with a Kb value of 2.50 × 103 L/mol. Moreover, an in-silico molecular docking method was performed, and it was revealed that the binding site of histamine was located closer to Lysine-131 in subdomain IIA of bovine serum albumin.

Comparative physical, antioxidant, and antimicrobial properties of films prepared by dissolving chitosan in bioactive vinegar varieties

Solvent casting following the dissolution of chitosan in aqueous acetic acid is the most widely used method for preparing chitosan films. In this study, an economical and practical way is proposed to improve the physicochemical properties of chitosan films by using vinegar varieties both as solvents and as bioactive additives to improve the properties of the films. Chitosan films were prepared by dissolving chitosan in pomegranate, grape, apple, and hawthorn vinegar. Vinegar contains bioactive phenolics and different organic acids together with acetic acid, depending on the main raw material from which it is obtained. The films' mechanical, optical properties, antioxidant and antimicrobial activities were compared with each other and with the chitosan film prepared by dissolving chitosan in acetic acid. The antioxidant and antimicrobial properties of chitosan films prepared with vinegar increased. The use of vinegar as a solvent increased the UV light barrier properties of the films. Improved antimicrobial, antioxidant, optical, and elastic properties of films prepared by dissolving chitosan in vinegar varieties are promising in applications of these films as potential and economic food packaging materials.

Efficient Photocatalytic Degradation of Methylene Blue Dye from Aqueous Solution with Cerium Oxide Nanoparticles and Graphene Oxide-Doped Polyacrylamide

A cerium oxide nanoparticles (CeO₂-NPs)/graphene oxide (GO)/polyacrylamide (PAM) ternary composite was synthesized through free-radical polymerization of acrylamide in the presence of CeO₂ nanoparticles and GO in an aqueous system. The synthesized composite material was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy techniques and applied for the photocatalytic degradation of methylene blue (MB) dye from an aqueous solution. Tauc's model for direct transition was used to model for the optical band gap. The key operating parameters such as the amounts of CeO₂-NPs and GO, pH, initial MB concentration, type of light irradiation, and contact time have been optimized to achieve the highest MB degradation percentage. The photocatalysis process was pH-dependent, and the optimum pH value was found to be 12.0. Under UV-A light, 90% dye degradation occurred in 90 min. The degradation of MB was also specified in terms of total organic carbon (TOC) and chemical oxygen demand (COD). Free-radical capture experiments were also performed to determine the role of radical species during the photocatalytic oxidation process. The photocatalytic process showed that the equilibrium data is in good agreement with the Langmuir-Hinshelwood kinetic model. A rate constant of 0.0259 min^-1 was obtained. The hydrogel was also tested to assess its reusability, which is an important key factor in practical wastewater treatment. The photocatalytic activity only decreased to 75% after nine uses.

Sample Stacking-Capillary Electrophoretic Analysis of Nitrate and Nitrite in Organic- and Conventional-Originated Baby Food Formulas from Turkey

Commercially available baby food formulas represent a convenient alternative to homemade meals especially in the recent years. The main purpose of this study is the determination of nitrate and nitrite levels by a sample stacking-capillary electrophoresis technique in the baby foods. The baby foods analyzed were organic-originated, vegetable-based, fruit-based, mixed puree, and a vegetable soup. Vegetables and fruits have high nitrate and nitrite concentrations. Nitrate itself is not actually hazardous. However, nitrite has negative health effects. Thus, baby foods have to be strictly controlled due to the potential health risk of nitrite. In this study, the sample stacking method enhanced the sensitivities of both anions. Nitrate contents ranged from 16.1 to 285 mg/kg with a mean concentration of 149 mg/kg for all samples. The lowest nitrate amount belonged to red fruity milky baby food whereas the highest nitrate was found in organic pumpkin, banana, and carrot mixed puree. The nitrite levels in all the samples were below the LOQ value of the analyzed method. As a conclusion, there is no health risk of the analyzed baby foods regarding nitrate and nitrite levels considering the regulations.

Antioxidant and antimicrobial chitosan films enriched with aqueous sage and rosemary extracts as food coating materials: Characterization of the films and detection of rosmarinic acid release

Chitosan films containing aqueous extracts of sage and rosemary were prepared as a potential food coating material with antioxidant and antibacterial properties. The effect of adding extracts at different concentrations on the mechanical, physical, and optical properties of the films was investigated. The addition of the extracts significantly increased Young's modulus values of the films compared to the chitosan film, and a significant decrease was observed in the swelling percentage and water vapor permeability of the films. Since all the prepared films were ionically cross-linked, the increase in water solubility of the films with the addition of the extract was at a low level. The release of rosmarinic acid, which is found in significant amounts in both plants, from the films was monitored by the capillary electrophoresis. The antioxidant properties imparted to the films by the addition of plant extracts were determined by DPPH and FRAP methods. The addition of plant extracts increased the antimicrobial property of chitosan films against Staphylococcus aureus and Escherichia coli. Films containing sage and rosemary extracts showed potential for use as food coating materials.

Sample stacking – Capillary electrophoretic determination of nitrate and nitrite contents as nitric oxide metabolites in honey varieties originated from Anatolia

Nitrate and nitrite ions taken from food are the sources of bioavailable nitric oxide (NO) in the nitrogen cycle. Some beneficial effects of honey on health are attributed to the ability of honey to increase NO production. The variation of nitrate and nitrite levels of honey samples collected from different Anatolia regions were clarified using capillary electrophoresis technique. The sensitivities of both anions were improved with the application of the sample stacking method. Separation buffer consisted of 30 mmol L−1 formic acid and 30 mmol L−1 sodium sulfate at a pH of 4.0. The CE technique revealed that 18 honey samples contained nitrate anion ranged between 2.53 and 31.8 mg kg−1. Nitrite amounts were found in lower amounts in the honey samples as between non-detected and 0.533 mg kg−1. The observed differences in nitrate levels between honey varieties may be a way to determine honey's origin.

Oleuropein levels of Anatolian olive leaves and correlated antioxidant, antidiabetic, and anti-inflammatory activities

Oleuropein, the major active compound in olive leaf, has been of considerable interest for its many health benefits. This work aims the determination of oleuropein in olive leaves from Turkey by a rapid and simple capillary electrophoretic method, and then to correlate the oleuropein amounts and the bioactivities of olive leaf extracts. The optimal separation medium was composed of 30 mmol/L borate (pH: 9.6), 25 mmol/L2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 10% (v/v) methanol. Moreover, olive leaf extracts were examined for antioxidant, antidiabetic, and anti-inflammatory activities. The antioxidant activities were determined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity. The antidiabetic activities were predicted using α-glucosidase inhibitory effects. For the anti-inflammatory activities of the extracts, their reduction power of pro-inflammatory tumor necrosis factor (TNF)-alpha were measured. Oleuropein concentration ranged between 11.7-106 mg/g dry leaf. Strong correlations were detected between each biological activity and the oleuropein content of olive leaves

Rosmarinic and carnosic acid contents and correlated antioxidant and antidiabetic activities of 14 Salvia species from Anatolia

Herbal medicine has been used worldwide as an alternative treatment. Salvia genus is one of the most remarked herbs which is traditionally used in the treatment of many diseases. Therefore, it is a crucial issue to reveal the chemical and biological profiles of different Salvia species. Rosmarinic and carnosic acid are the most well-known bioactive components generally accepted as the main antioxidant compounds in Salvia. This study firstly aims the determination of rosmarinic and carnosic acid contents of 14 Anatolian Salvia species by a simple and rapid capillary electrophoresis method. Moreover, the antioxidant activities and total phenolic contents of the Salvia samples were investigated. α-Glucosidase enzyme inhibitory effects of the samples were tested concerning their antidiabetic activities. The rosmarinic acid contents in the samples were well-correlated with the bioactivities.

Nitrate and Nitrites in Foods: Worldwide Regional Distribution in View of Their Risks and Benefits

Nitrate and nitrite ions are used as food additives to inhibit the growth of microorganisms in cured and processed meats. Vegetables contain significant quantities of nitrate and nitrite. Actually, the vast majority of consumed nitrate and nitrite comes from natural vegetables and fruits rather than food additives. For years, the cancer risks of these two ions have been discussed, since they potentially convert into the carcinogenic nitrosamines. However, recently, these two ions have been considered essential nutrients which promote nitric oxide production and consequently help cardiovascular health. It seems that the role of these two ions in our diet is important now from a different point of view. In this review, the nitrate and nitrite contents of food products from different countries are displayed globally in order to reinterpret the risks/benefits of our consumption quotations. This review article is based on Science Citation Index (SCI) articles reported between 2008 and 2018.

α-Glucosidase enzyme inhibitory effects and ursolic and oleanolic acid contents of fourteen Anatolian Salvia species

During the last decade, ursolic and oleanolic acids have been of considerable interest because of their α-glucosidase inhibitory activities and potential effects for treatment of type 2 diabetes. A simple and sensitive reversed-phase HPLC method was developed for the simultaneous determination of ursolic acid and oleanolic acid. The optimal mobile phase was selected as 85% acetonitrile solution. The limit of detection of the method for ursolic acid and oleanolic acid were 14 ng mL-1 and 13 ng mL-1, respectively. The method showed good precision and accuracy with intra-day and inter-day variations of 0.54% and 7.33% for ursolic acid, intra-day and inter-day variations of 0.51% and 5.26% for oleanolic acid, and overall recoveries of 97.8% and 98.5% for ursolic acid and oleanolic acid, respectively. Application of the method to determine the ursolic acid and oleanolic acid contents in the Salvia species revealed both compounds, with varying amounts between 0.21-9.76 mg g-1 ursolic acid and 0.20-12.7 mg g-1 oleanolic acid, respectively, among 14 Salvia species analyzed. Additionally, the plant extracts were analyzed for their inhibitory activities on α-glucosidase. According to the results of this assay, the extracts showed considerable activity on α-glucosidase with IC50 values from 17.6 to 173 μg mL-1. A strong negative correlation was detected between the amounts of both acids and IC50 values of extracts. Anatolian Salvia species have great potential as functional plants in the management of diabetes.

Antimicrobial and physical properties of chitosan films incorporated with turmeric extract

In this study, the effects of turmeric extract incorporation on the antibacterial and physical properties of the chitosan films were evaluated. Turmeric containing chitosan-based film was produced with casting procedure and cross-linked with sodium sulfate. Mechanical, optical, thermal properties, and water vapor permeability of the films were studied. The addition of turmeric to chitosan film significantly increased the tensile strength of the film and improved the ultraviolet-visible light barrier of the film. Infrared spectroscopy analysis suggested an interaction between the phenolic compounds of the extract and amin group of chitosan. Antimicrobial activity of the chitosan films was studied against Salmonella and Staphylococcus aureus by plate count agar technique and a better antimicrobial activity was observed with turmeric incorporation. Turmeric incorporated chitosan films with enhanced antimicrobial activity and film stiffness can be suggested as a promising application for food packaging.

Comparison of antioxidant, anticholinesterase, and antidiabetic activities of three curcuminoids isolated from Curcuma longa L

Antioxidant, anticholinesterase and antidiabetic activities of three curcuminoids isolated from the Curcuma longa were simultaneously tested and compared in this study. The highest antioxidant power was detected for curcumin with the applied methods. The drug potentials of curcuminoids for Alzheimer's disease were controlled. Bisdemethoxycurcumin (BDMC) showed substantial inhibitory activity. The activity of demethoxycurcumin (DMC) followed BDMC, whereas curcumin showed very little acetylcholinesterase inhibition activity. Antidiabetic activity of curcuminoids was evaluated by their α-glucosidase inhibitory activities. All curcuminoids show activities with decreasing order as BDMC > curcumin > DMC. The significant activities of BDMC compared to its isomers and examination of chemical structures of isomers might be a starting point in designing new drugs for Alzheimer's and Diabetes Mellitus.