Species of the Genus <i>Salix</i> L.: Biochemical Screening and Molecular Docking Approach to Potential Acetylcholinesterase Inhibitors

The genus Salix includes about 500 different, mainly woody species with potentially significant medicinal values. The aim of this study was to evaluate the chemical composition and antioxidant activity of little-studied bark and leaves extracts of seven different species of the genus Salix, and to examine the acetylcholinesterase (AChE) inhibitory potential of selected compounds. The extracts were characterized by High Pressure Liquid Chromatography (HPLC). Total phenolics and flavonoids content was determined spectrophotometrically and the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH&#8226;) and hydroxyl radical (&#8226;OH) scavenging assays. Molecular docking studies were conducted in order to elucidate the interaction and binding affinity between selected compounds of willow bark and leaves against AChE. The major components in bark and leaves of most of the species were rutin (1.26&#8722;22.09 mg/g), salicin (1.62&#8722;17.33 mg/g), chlorogenic acid (0.74&#8722;7.53 mg/g) and epicatechin (0.71&#8722;4.83 mg/g). The latter three compounds demonstrated significant inhibitory potential against AChE in docking studies. All extracts exhibited notable antioxidant activity as scavengers of both DPPH&#8226; and &#8226;OH. The obtained results indicate that willow species other than those in commercial use, and not only bark, but willow leaves as well, could be utilized as sources of valuable phytocompounds with antioxidant and neuroprotective properties

Analysis of operating variables for Yerba mate leaves supercritical carbon dioxide extraction

Given the increasing demand for potassium in Brazil, the mining and use of carnallite is becoming increasingly important, because the current source of potassium, sylvinite, is being depleted and there is a risk of shortages. Based on theoretical and practical data available in existing literature, this work describes the development, simulation, and economic feasibility of a process for dissolution and crystallization of potassium chloride from carnallite ore. Positive results were obtained following the application of the Hoffman diagram and determination of the corresponding equation. The proposed process provided over 85% potassium chloride crystallization, demonstrating its superior performance, compared to existing procedures

Influence of the structure of bile acids on their partition coefficient in dibutyl ether and chloroform

Bile acids are well known natural surfactants able to modify the per­meability of biological membranes. The logarithm of partition coefficient between, tradi­tionally used, n-octanol and water is a measure of lipophilicity as a predictor of solute membrane partitioning. The aim of this work was to determine partition coefficients of bile acids in a mixture of water and chloroform and dibutyl ether at different pH values and with addition of different concentrations of sodium ions, and to examine the influence of the structure of bile acid nucleus on measured partition coefficients. Partition coefficients of three bile acid salts were determined using shake-flask method and the concentration of bile acids was determined after twelve hours of shaking at the room temperature in aqueous and organic layer using reversed phase HPLC with DAD detector on 210 nm. For all three analysed bile acid salts values of logP are lower in dibutyl ether than in chloroform. At certain pH values, curves representing the dependence of partition coeffi­cient on pH value intersect, and these are the pH values for which partition coefficients are the same for both solvents. Increasing the solution ionic strength, this intersection is shifted toward lower pH values. It is found that, for both organic solvents, after the addition of hy­droxyl group in the steroid nucleus (i.e. if the bile acid is less hydrophobic) the value of logP falls, especially if more hydroxyl groups are present. With chloroform as a solvent, system quickly comes to excess with electrolyte ions than with dibutyl ether. [Projekat Ministarstva nauke Republike Srbije, br. 172021

Determination of 5-caffeoylquinic acid (5-CQA) as one of the major classes of chlorogenic acid in commercial tea and coffee samples

Background/Aim. Tea and coffee are one of the most widely consumed beverages in the world due to their beneficial health effects which are largely associated with their phenolic compounds composition, including chlorogenic acid. The main aim of this study was to determine 5-caffeoylquinic acid (5-CQA), as one of the major classes of chlorogenic acid, in various commercial tea and coffee samples present at the Serbian market. Methods. A high-performance liquid chromatography (HPLC) method for determination of 5-CQA in plant extracts was applied to determine the content of this active compound in commercial tea and coffee samples. Mobile phase was aqueous 1.5% acetic acid - methanol (80:20, v/v) with the flow rate of 0.8 mL/min. Run time was 15 min and column temperature 25°C. The detection was performed at 240 nm. Results. The HPLC method was modified and revalidated. The 5-CQA content varied depending on the type of tea (white, green, black tea and mate) and the processing technology. Green tea had the highest 5-CQA content (16 mg/100 mL) among the analyzed tea samples. The content of 5-CQA in coffee samples ranged 0-36.20 mg/g of coffee and 0-46.98 mg/100 mL of beverage, showing that the content varied depending on the type of coffee, coffee processing technology and the formulation. Conclusion. The modified and revalidated HPLC method showed a good accuracy, repeatability, selectivity and robustness. The highest amount of 5-CQA was determined in green tea in comparison to white, black and mate tea because the increased oxidation level decreases the amount of 5-CQA. The obtained results for commercial coffee samples indicated that the formulation was the most important factor determining the amount of 5-CQA. It can be concluded that plant material selection, processing conditions and formulation have great influence on the amount of chlorogenic acid (5-CQA) in the final tea and coffee products. [Projekat Ministarstva nauke Republike Srbije, br. OI 172058

Activity of Serbian Aronia prunifolia against Prototheca wickerhamii and Prototheca zopfii

Background: Beneficial effects of berries have been known from 16th century, but their antimicrobial effects have been explained scientifically only recently. The two most common aronia species are black chokeberry, Aronia melanocarpa [Michx.] Elliot and red chokeberry, Aronia arbutifolia [L.] Elliot. Purple chokeberry (Aronia prunifolia) is a hybrid of these two species. Protothecosis is a disease caused by achlorophyllous algae Prototheca species. Infections with Prototheca species are more common in veterinary medicine. The purpose of this study was to investigate the activity of Aronia prunifolia berries against Prototheca zopfii (P. zopfii) and Prototheca wickerhamii (P. wickerhamii).Materials, Methods & Results: Purple chokeberry juice was made by squeezing the fruits and evaporated to dryness. Extracts of purple aronia were obtained by maceration with ethanol 80 % (v/v) for 24 h. Prototheca zopfii was obtained from udder of cow with mastitis and Prototheca wickerhamii was isolated from human oral cavity. Total phenolic and flavonoid contents were analized using spectrophotometric methods. The chemical composition of the tested substances was determined by a high performance liquid chromatography (HPLC) method. The examination was conducted by a micro-dilution method according to the guidelines of Clinical and Laboratory Standards Institute (CLSI). Microsoft Excel program 2007 was used for statistical analysis. The antialgal activity was expressed as minimal inhibitory concentrations MIC99, MIC90 and MIC80, the lowest concentration which kills 99%, 90% and 80% of organisms, respectively. Furthermore, minimal algaecide concentration (MAC), the lowest concentration which kills 99.9% of organisms is determined, as well as break point, the lowest concentration at which there is no algal growth.Discussion: The content of ascorbic acid was twice as high in the ethanolic extract as in the juice. Content of polyphenolic compounds was high in both juice and ethanolic extract. The quantity of phenocarbonic acids in juice and ethanolic extract was relatively low. Some of them were found only in juice (ellagic, coumaric and gentisic acids) as opposed to others found only in ethanolic extract (chlorogenic acid). Flavonoids were also detected in juice and ethanolic extract. Extract was much richer in flavonoid content when compared to aronia juice. Catechin was present in concentration of 186.3 mg/ 100 g of dry matter in the aronia juice, and 680.65 mg/ 100 g of dry matter in the ethanolic extract, which was more than 3.6 times higher. Quercetin was found only in the extract. The rutin content was 12 times and the chrysin content was 2.5 times higher in the aronia extract. The biggest difference could be noted in the quantitative contents of anthocyanins, 26 times higher concentration in extract than in juice. In general, higher content of bioactive compounds could be observed in the extract than in the juice. The results showed that the ethanolic extract of aronia fruits exhibited antialgal activity against both Prototheca species, while the juice showed no antialgal activity. This difference in antialgal effect is presumably related to the high content of several groups of biocompounds, especially catechin and anthocyanins, present in the ethanolic extract, and probably their synergistic action. There is no comparable data of antialgal effects of aronia in literature

Industrial emerging chemicals in the environment

In the recent time, considerable interest has grown concerning the presence of the emerging industrial chemicals, EmIC. They are contaminants that have possible pathway to enter to the environment and they are dominantly released by industrial and anthropogenic activities. EmIC are applied in different fields using as industrial chemicals (new and recently recognized), global organic contaminants (flame retardant chemicals), pharmaceuticals (for both human and animal uses), endocrine-modulating compounds, biological metabolites, personal care products, household chemicals, nanomaterial (energy storage products, lubricants), anticorrosive and agriculture chemicals and others that are applied to a wide variety of everyday items such as clothing, upholstery, electronics and automobile interiors. NORMAN (Network of reference laboratories for monitoring of emerging environmental pollutants) has established an open, dynamic, list of emerging substances and pollutants. EmIC have been recently detected in the environment due to their long-term presence, pseudo-persistence and increased use. Improvements in sophisticated analytical methods and time integrative passive sampling have enabled the identification and quantification of EmIC, in very low concentrations (ppb, ppt and lower), which likely have been present in all environmental mediums for decades. Passive technology is an innovative technique for the time-integrated measurement of emerging contaminants in water, sediment, soil and air. Passive samplers are simple handling cost-effective tool that could be used in environmental monitoring programmes. These devices are now being considered as a part of an emerging strategy for monitoring a range of emerging industrial chemicals and priority pollutants in the aquatic environment. EmIC are substances that are not included in the routine monitoring programmes and whose fate, behaviour and (eco)toxicological effects are still not well understood. Emerging pollutants have no regulatory standards based on peer-reviewed science. EmIC might jeopardize aquatic environment. The first screening analyses of emerging industrial and priority organic contaminants in the Danube surface water, in the vicinity of Novi Sad, have been done and approximately more than 140 compounds have been registered. The new sampling campaign, screening and target analyses are in progress. [Projekat Ministarstva nauke Republike Srbije, br. III46009