Influence of process parameters on hawthorn (Crataegus Monogyna Jack.) extraction

Given that many synthetic medications can induce a variety of negative reactions in patients, a search for natural substances with minimal side effects in patients has been conducted. Nowadays, researchers are focusing on plant medicines, which have been used to heal illnesses since ancient times. The plant Crataegus monogyna Jack. (hawthorn) is the most abuntant plant in the Rosaceae family that is also used in traditional medicine. C. monogyna\u27s pharmaceutical, phytochemical, functional, and therapeutic qualities are based on a wide range of useful secondary metabolites, which include phenolic compound (flavonoids, anthocyanins, tannins), vitamin C and antioxidants. Total (poly)phenols, flavonoids and anthocyanins contents in C. monogyna Jacq. extracts were measured using the Folin-Ciocalteu reagent, aluminium chloride and the pH differential methods, respectively. The extraction lasted 15 to 120 min, with a solid-to-solvent ratio of 1:15 w/v and 1:30 w/v and solvents of 30% and 60% ethanol. According to the results, the extraction process has the highest velocity within the first 15 min, when the majority of (poly)phenols and flavonoids are extracted, but it becomes slower as time passes. Higher yields are obtained by utilizing a solid-to-solvent ratio of 1:30 w/v rather than a solid-to-solvent ratio of 1:15 w/v, which indicates that when the amount of drug increases over a certain optimal value, the resistance to mass transfer from a solid material to liquid increases. Finally, the results about the impact of the ethanol content in the solvent demonstrate that a larger ethanol content greatly favors the extraction of flavonoids, but this is not as evident for the extraction of total (poly)phenols and anthocyanins

Određivanje Au i Ag iz rude gvožđa kombinovanjem FA i ICP/AES metoda

In this paper, the combination of FA (Flame Analysis of Noble Metals - Cupellation) and ICP/AES (Atomic Emission Spectrometry with Induction Coupled Plasma) methods for determination of Au and Ag in geological samples of iron ore-magnetite was presented. Au and Ag were concentrated with Pb from PbO after desulphurisation and melting process (Pb2+→Pb). Regulus (Pb with noble metals) is then cupellated. The resulting bead-pril after cupellation was dissolved in HNO3 and then in HCl (imperial water: 2HNO3 and 6HCl). After the preparation of standard solutions and a blank test, the ICP/AES recording is performed. The obtained results were compared with those obtained by the classical method of cupellation. The advantages of ICP/AES are excellent detection limits and linear dynamic range as well as a stable and repeating signal which is particularly important for samples of iron tested due to the low content of noble metals.U ovom radu je prikazana kombinacija FA (plamena analiza plemenitih metala-kupelacija) i ICP/AES (atomska emisiona spektrometrija sa indukovanom kuplovanom plazmom) metoda za određivanje Au i Ag u geološkim uzorcima rude gvožđa-magnetit. Au i Agse koncentišu sa Pb iz PbOnakon procesa odsumporavanja i topljenja (Pb2+→Pb).Regulus (Pb sa Au i Ag)se kupelira. Dobijena perla-pril nakon kupelacije se rastvara u HNO3 a zatim u HCl(carska voda 2HNO3: 6HCl). Nakon pripreme standardnih rastvora i blank probe vrši se snimanje na ICP/AES. Dobijeni rezultati su poređeni sa rezultatima dobijenim klasičnom metodom kupelacije. Prednosti ICP/AES su odlične granice detekcije i linearni dinamički opseg kao i stabilan i ponovljiv signal što je posebno bitno za uzorke ispitivane rude gvožđa zbog malog sadržaja plemenitih metala

Biochemical changes in myofibrillar and sarcoplasmatic meat proteins at different freezing rates

Freezing rate significantly affects the quality of frozen meat and its biochemicalchanges. The loss of water from the cellular structure, which, under normal conditions,acts as a mechanical barrier between protein chains, causes spontaneousinteractions of proteins that result in their denaturation. In order to determinethe content of myofibrillar and sarcoplasmic proteins in meat samples, the sampleswere frozen at rates of 0.40, 0.90, and 1.25 cm/h for a storage period of 15 days.Protein content was analyzed by capillary gel electrophoresis and high-pressure liquidchromatography. During the freezing process, the protein chains were found tobe shortened so that myofibrillar proteins were between 20 and 50 kDa, whereassarcoplasmic proteins were between 20 and 100 kDa at all the freezing rates mentioned.The results of the analysis also show that the total number of sarcoplasmicproteins (freezing rate 0.90 cm/h; 20 proteins) was lower than the total numberof myofibrillar proteins (freezing rate 0.90 cm/h; 35 proteins), and the molecularweight for both types of protens was lower 50 kDa. Further research should bedirected towards extending storage time

INFLUENCE OF CRYSTALLIZATION TEMPERATURE ON THE ABSORPTION OF DIBUTYL PHTHALATE IN ZEOLITE A

In order to determine the effect of crystallization temperature on the absorption and properties of zeolite A particles, we have monitored the modified dibutyl phthalate absorption ( DBP ), a degree of crystalline phase, specific surface area, mean diameter of particle ( DS50 % ), and performed scanning electron microscopy ( SEM ) of the synthesized samples of zeolites. The synthesis of samples was carried out at crystallization temperatures of 70, 75, 80, 85 and 90°C ; the raw materials (sodium aluminate and sodium silicate) were heated at 90°C. The particle size of the synthesized samples is similar in most studied systems at all temperatures of crystallization, which is in accordance with the principles of the autocatalytic nucleation and „memory effect” of the gel. An increase in the specific surface area of the synthesized samples with the increase in the crystallization temperature was observed in all the analyzed systems (3.25 to 35.31 m2/g). It was found that the increase of crystallization temperature increases the absorption of dibutyl phthalate(0.90-1.20  cm3/g ); however, at the same time, the proportion of zeolite A in the same samples is reduced, as confirmed by SEM analysis.In order to determine the effect of crystallization temperature on the absorption and properties of zeolite A particles, we have monitored the modified dibutyl phthalate absorption ( DBP ), a degree of crystalline phase, specific surface area, mean diameter of particle ( DS50 % ), and performed scanning electron microscopy ( SEM ) of the synthesized samples of zeolites. The synthesis of samples was carried out at crystallization temperatures of 70, 75, 80, 85 and 90°C ; the raw materials (sodium aluminate and sodium silicate) were heated at 90°C. The particle size of the synthesized samples is similar in most studied systems at all temperatures of crystallization, which is in accordance with the principles of the autocatalytic nucleation and „memory effect” of the gel. An increase in the specific surface area of the synthesized samples with the increase in the crystallization temperature was observed in all the analyzed systems (3.25 to 35.31 m2/g). It was found that the increase of crystallization temperature increases the absorption of dibutyl phthalate(0.90-1.20  cm3/g ); however, at the same time, the proportion of zeolite A in the same samples is reduced, as confirmed by SEM analysis

Eco-friendly microwave-assisted synthesis of biologically active naphthenic acid n-cyclohexyl amides

Inside the framework of green chemistry, a noticeable results were obtained in microwaveassisted solvent-free synthesis of biologically active N-cyclohexyl amides of naphthenic acids (NAs). Naphthenic acid amides were synthesized directly from free carboxylic acids in the absence of solvent and catalyst. Synthesized N-cyclohexyl amides of naphthenic acid were evaluated for their auxin activity

Bio-renewable membranes based on modified cellulose, lignin, and tannic acid for difenoconazole and thiophanate-methyl removal

Aquatic pollution caused by pesticides as a consequence through run-off, leaching, and subsurface drainage, may pose a serious health hazard for living being and ecosystems due to pesticides persistent nature and bio-magnification. Since most organic pesticides are nondegradable and carcinogenic, they represent a potent category of water contaminants. The aim of the presented work was to develope functional biodegradable membranes which could be used as an efficient adsorbent for the removal of pesticides (difenoconazole and thiophanate-methyl) from aquatic solutions. The bio-renewable membranes (Cell-El and Cell-El-Ta) based on epoxyamino reactivity of the Cellulose fibres (Cell) modified with diethylenetriamine (Cell‒Deta), (3- Glycidyloxypropyl)trimethoxysilane (Cell-Glymo), Lignin modified with epichlorohydrine (El) and Tannic acid (Ta), as an additional crosslinker, were produced by optimized methods through the application of novel approaches. The membrane preparation was conducted at the appropriate molar ratio of functional groups designed to provide numbers of residual functionalities effective for pesticide removal. The membranes were characterized by FourierTransform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). FTIR spectral analysis was used to identify the characteristic functional groups of produced membranes and spectral pattern change as a result of the formation of coordination complexes of pesticides with surface functionalities. Controlled modification of Cell fibre and subsequent production of Cell-El and Cell-El-Ta membrane causes change fibres surface and material morphology, and SEM analysis proved successful modification and membrane production with formation a large number of fibres interconnections. The effects of contact time, temperature, and initial concentration of pesticides on adsorption were studied in a batch system. The Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) isotherm models were used to evaluate the adsorption process, and to predict the adsorption capacity of the adsorbents. The experimental results were best fitted with the Langmuir isotherm model. The calculated capacities: 32.2, 69.3, 45.1 and 83.2 mg g-1 for difenoconazole and thiophanate-methyl using Cell-El and Cell-El-Ta, respectively, were obtained from Langmuir model fitting at 25oC. The thermodynamic parameters indicated spontaneous and low endothermic processes. The present study demonstrates that prepared membranes could be an effective and low-cost adsorbent to prevent contamination of water and consequently help minimize the environmental impact caused by the pesticides

Metal and metalloid bioaccumulation in three centipedes (Chilopoda)

Three centipede species (Clinopodes flavidus, Cryptops anomalans and Eupolybothrus transsylvanicus) were used as bioindicators of trace metal and metalloid pollution in Belgrade, Serbia. The concentrations of 13 elements (the metals Mn, Co, Ni, Cu, Zn, Rb, Sr, Cd, Tl, Pb and U and metalloids As, Se) in whole animals and soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). Differences in the concentrations of some elements in the analyzed species were observed, both in response to the sites and between species. In most cases, the trace element concentrations were higher in centipedes from a polluted site (an industrial area near a busy street with heavy traffic) but C. anomalans and E. transsylvanicus had higher Mn concentrations at an unpolluted site (a deciduous woodland on Mt. Avala). C. flavidus was a good bioindicator for detecting differences between Zn, Se and Cd. C. flavidus and C. anomalans were more efficient in accumulating Zn than E. transsylvanicus. It appears that C. anomalans poorly accumulated Cd, unlike C. flavidus and E. transsylvanicus, which accumulated Cd according to the high bioaccumulation factor (BAF) values. We conclude that the centipedes C. flavidus, C. anomalans and E. transsylvanicus can be used as suitable bioindicators of trace element exposure. Their ability to accumulate trace elements was different and depends on their physiology and lifestyle as well as the route of exposure.Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/5673

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Estimation of antioxidative potential of thyme (Thymus alpestris L.)

Family Lamiaceae (labia) includes a large number of cosmopolitan speciesincluding Thymus alpestris (Thyme) characterized by the presence of essential oilsand phenolic compounds. It represents a perennial semi-shrubby plant. Theantioxidant potential of thyme is due to the presence of polyphenolic acids andflavonoids. The topic of this paper is the extraction of thyme (Thymus alpestris)with 40% ethanol and 50% ethanol, using Soxhlet method (circulatoryextraction), after which, the content of phenolics and flavonoids was determinedin order to confirm the antioxidant potential of this plant species. The resultsshow that 40% ethanol extract has the highest content of phenolics andflavonoids and the highest antioxidant potential, resultingly