Досліджено якісний склад та кількісний вміст вторинних метаболітів рослин Colobanthus quitensis (перлин- ниці антарктичної) з районів Південних Шетландських островів, Берега Греяма і Берега Данко. Порівняно склад і антиоксидантні властивості екстрактів, вилучених із рослин перлинниці, що зростали на різних локаціях у природному середовищі та в умовах in vitro. Також було зіставлено склад і властивості екстра- ктів перлинниці та екстракту іншої антарктичної рослини — щучнику антарктичного (Deschampsia antarctica). Біохімічний склад екстрактів вивчено методами високоефективної рідинної хроматографії та масспектрометрії з матрично-активованою лазерною десорбцією / іонізацією; антиоксидантні властивос- ті досліджено за допомогою DPPH-тесту. Встановлено, що всі екстракти перлинниці характеризуються високим вмістом фенольних сполук (до 38 мг/г сирої сировини) і виявляють значну антиоксидантну / ан- тирадикальну активність (інгібують до 90 % DPPH радикалів за 30 хв). Показано, що антирадикальна активність досліджених екстрактів корелює із загальним вмістом антиоксидантів у зразках. Екстракти з нативних рослин перлинниці містять в основному флавоноїди (глікозиди апігеніну, лютеоліну та мети- лових ефірів лютеоліну), частка яких становить ~90 % загального вмісту фенольних сполук; інші ~10 % фенольних антиоксидантів складають гідроксибензойні та гідроксикоричні кислоти. В екстракті з куль- тури in vitro, навпаки, переважають фенольні кислоти (~58 %). Біохімічний склад досліджених екстрактів перлинниці відрізняється від складу екстракту щучнику значно більшим відносним вмістом похідних апіге- ніну (16—43 % загального вмісту фенольних сполук проти 3 % у щучнику) та меншим вмістом похідних лю- теоліну (46—71 % проти 79 % у щучнику) і фенольних кислот (9—13 % проти 18 % у щучнику). Порівняно з екстрактом щучнику в досліджених екстрактах перлинниці загальний вміст фенольних сполук нижчий і, відповідно, здатність цих екстрактів інгібувати DPPH радикали менша. Незважаючи на це, Colobanthus quitensis, як і Deschampsia antarctica, також є ефективним продуцентом цінних природних антиоксидантів.

The reactions of benzoyl chloride and different aliphatic sodium carboxylates catalyzed by pyridine derivatives in a two-phase water/organic solvent system were studied. The effects of catalyst struc-ture, initial concentration of catalyst and carboxylate ion in the aqueous phase, temperature, and po-larity of organic solvent on the formation rate and yield of mixed anhydride were investigated in detail. 4-methylpyridine N-oxide, 4-methoxypyridine N-oxide, 4-morpholinopyridine N-oxide, and 4-dimethylaminopyridine were used as catalysts. A higher reaction rate was achieved with use of 4-methylpyridine N-oxide. In contrast to literature data, it was found that the reaction between ionic in-termediate and carboxylate ion is a rate-determining step rather than the reaction of ionic intermediate formation. Both linear and branched carboxylates were used to study the effect of carboxylate ion struc-ture on the reaction rate and yield of the mixed anhydrides.(c) 2023 Elsevier B.V. All rights reserved.

Evaluation of intramolecular hydrogen bond energies of twenty gossypol imine derivatives was carried out using 1H NMR spectroscopy and quantum chemistry methods. Gossypol imine derivatives contain various intramolecular hydrogen bonds: O-H⋯O, N-H⋯O, O-H⋯N, C-H⋯O and O-H⋯π. The existence of dienamine and diimine tautomeric forms causes some differences in the intramolecular hydrogen bonding of these compounds. It was found that the position of the O-H group proton signals in the 1H NMR spectra made it possible to provide an initial estimation of the hydrogen bond energies and the degree of proton involvement in non-covalent interactions. Using geometric characteristics, hydrogen bond length, distance between electronegative atoms involved in the hydrogen bonding, and hydrogen bond angle, made it possible to compare the energies of all intramolecular hydrogen bonds of the studied gossypol imine derivatives in the gas phase. It was shown that the strengths of the intramolecular hydrogen bonds C(6)O-H⋯OC(7) are different for compounds in dienamine and diimine tautomeric forms, which may be a key factor affecting the tautomeric equilibrium of this class of compounds.

It is established that crystalline graphite-like carbon nitride (CGCN) exhibits high photocatalytic activity in the process of chemoselective reduction of furfural to furfuryl alcohol in the presence of co-catalysts under the action of visible light by electron-donating substrates, such as methanol/water and ethanol/water, in an acidic medium. When palladium chloride additives are introduced into the reaction mixture, the rate of the process is higher than with the participation of the Pd/SiO2 co-catalyst. This phenomenon may be due to the in situ formation of the CGCN/Pd0 composite photocatalyst in the presence of PdCl2, where the photogenerated charges are better separated than in the CGCN-Pd/SiO2 system. The effective quantum yield of furfural reduction is 56

The photocatalytic conversion of lignin, obtained from camelina ( Camelina sativa ), over titania and iron titanate films has been studied with analysis of the products using laser desorptiopn/ionization and high-performance liquid chromatography. The photocatalytic reaction over titania films leads to the formation of the mixture of compounds, such as phenol, vanillic acid, resorcinol, and p -coumaryl alcohol. In the presence of iron titanate films, the predominant reaction products are vanillic acid and p -coumaryl. The highest antioxidant activity has been revealed in the case of lignin conversion products obtained over nitrogen-containing iron titanate films under visible light exposure.

The inverse phase transfer process of catalytic benzoylation of α-amino acids (on the example of alanine) in a two-phase water–dichloromethane system in the presence of pyridine derivatives as catalysts is investigated. The effect of the initial concentration of alanine, its form in solution, and the initial catalyst concentration on the reaction rate and the composition of the products is studied. It is established that using 4-methyl- and 4-methoxy pyridine N-oxides combined with a double excess of the sodium salt of alanine makes it possible to obtain 2-benzamidopropionic acid with a yield of more than 80

The aim of this work was to synthesize cerium oxide nanoparticles (CeO2-NPs) using the Magnolia kobus leaves extract, to determine the composition of the extract and the participation of its components in the synthesis of NPs, to study the morphology and structure of the obtained NPs, to investigate their antibacterial activity. The composition of the plant extract and involving of its components in green synthesis of CeO2-NPs was studied by high-performance liquid chromatography (HPLC) and matrix-assisted laser/desorption ionization mass spectrometry (MALDI MS). It has been shown that the extract contained phenolic compounds (derivatives of simple phenols, flavonols, hydroxybenzoic and hydroxycinnamic acids, lignans, coumarins), as well as carotenoids, chlorophylls, terpenoids and sterols. The composition of the liquid phase from the reaction mixture (reaction liquid) after the NPs formation was studied to determine the components of the extract involved in the synthesis of CeO2-NPs. According to the results of HPLC and MALDI MS studies, significant differences were found in the composition of the plant extract and the reaction liquid: hydroxybenzoic acids, flavonoids and terpenoids disappeared or their concentration was significantly decreased, the content of lignans changed to a lesser extent, and it was observed the appearance of hydrophilic low-molecular compounds probably formed as a result of synthesis and stabilization of NPs. Synthesized CeO2-NPs were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). According to SEM and XRD, CeO2-NPs had a crystalline structure and were of spherical shape; the average size of the crystallites was ~ 20 nm, and the diameter of the primary particles was 50 ± 10 nm. It has been found that hydroxybenzoic acids, flavonoids and terpenoids are active participants in the green synthesis of CeO2-NPs in the presence of Magnolia kobus leaves extract, while lignans (fargesin/kobusin and eudesmin) are involved in less extend in the reduction/stabilization of CeO2-NPs. The synthesized particles possess antibacterial properties and can be used in the preparation of materials for medical and biological purposes.

The aim of the work is to compare the microporous structure characteristics of activated carbons (ACs) prepared from coals of different coals rank (CR) by alkaline activation (RKOH = 1 g/g, 800 °C) and to determine the ACs capability to adsorb phenol and 4-chlorophenol from aqueous solutions. Starting materials are coals with increasing carbon content (Cdaf = 80.0–95.6 %) selected as a CR criterion. ACs were obtained in argon in three stages: 1) thermoprogrammed heating (4 grad/min) to 800 °С; 2) isothermal exposure 1 h; 3) cooling, washing from alkali and drying. Based on low-temperature (77 K) nitrogen adsorption-desorption isotherms, integral and differential dependences of the specific surface area S (m2/g) and pore volume V (cm3/g) on the average pore diameter (D, nm) were calculated. They were used to define volumes of ultramicropores (Vumi), supermicropores (Vsmi) and micropores (Vmi). The total pore volume Vt was calculated from the nitrogen amount adsorbed at a relative pressure p/p0 ~ 1.0. The S values of ultramicropores (Sumi), supermicropores (Ssmi) and micropores (Smi) were similarly determined. The volumes and specific surfaces of different categories of pores were found to decrease with CR increase: volume Vt – from 0.59 to 0.23 cm3/g; Vmi – from 0.51 to 0.17 cm3/g; the ultramicropores volume – from 0.31 cm3/g to zero in anthracite AC. The supermicropores volume is almost independent on CR and varies in the wide range Vsmi = 0.15–0.22 cm3/h. The specific surface area is the maximum (S = 1547 m2/g) in AC from the coal of the lowest CR and decreases with coal metamorphism up to 322 m2/g. The micropores surfaces make dominant contributions to the S values: its portion is 94.7–99.4 %. For all ACs, the adsorption of phenol (Ph) and 4-chlorophenol (CPh) from aqueous solutions at 25 °C was studied. Adsorption kinetics and isotherms are best described by the pseudo-second order model and the Langmuir model (R2 ≥ 0.998). With increasing CR, the maximum adsorption capacities decrease from 3.113 to 1.498 mmol/g (Ph) and from 3.9 to 2.1 mmol/g (CPh), that is approximately ~2 times when the specific surface area decreases by ~5 times. The Ph and CPh specific capacities, characterizing the adsorption capacity of 1 m2 of surface, change little at Cdaf≤86 %, but markedly increase (2.3–2.5 times) for anthracite AСs. The Ph and CPh capacitances were determined to increase linearly (R2 ≥ 0.966) with increasing ACs specific surface area. Similar dependences were found on the Sumi and Smi parameters. The phenols were concluded to be equally adsorbed on the surface of pores of any size. A general trend was found for ACs from hard coals and anthracite: an increase in CR reduces the ACs microporosity and surface, decreases Ph and CPh capacities but increases specific capacities, i.e. concentrations of surface adsorption centers. The Ph and CPh adsorption was accepted to include the interaction of π-electrons of phenolic rings and π-electrons of graphene layers in ACs, the formation of complexes with surface groups and forming hydrogen bonds with OH-groups. Their contributions depend on adsorbate nature and change with the growth of fossil coals CR.

The aim of this work was to study the polyphenolic composition of Deschampsia antarctica E. Desv. plants grown in natural conditions at different locations on the Galindez Island, Argentine Islands, the maritime Antarctic. The plants were collected during the summer season of the 26th Ukrainian Antarctic Expedition (2020-2022). The extracts of 21 plants were obtained and the composition of the extracts was analyzed by means of high-performance liquid chromatography and matrix-assisted laser desorption/ionization mass spectrometry. The antioxidant properties of the extracts were characterized using the DPPH (2,2-diphenyl-1-picrylhydrazyl) test. The extracts contained large amount of polyphenolic compounds, with flavonoids and phenolic acids, as well as their derivatives, being the most common classes of the phenols. Using the HPLC data the content of various phenols in the plants was systematic studied. It has been found that in all plants the most abundant phenols were flavonoids/flavonoid derivatives (on average about 75% of total mass of phenols). Among the flavonoids, luteolin derivatives predominated (86-94% of the total mass of flavonoids), and, among luteolin derivatives, the main compounds were orientin, orientin 2"-O-beta-arabinopyranoside and isoswertiajaponin 2"-O-beta-arabinopyranoside (67-83% of the total mass of luteolin derivatives). It has been also found that all the extracts had high activity in inhibition of DPPH radicals and that the antioxidant activity of the extracts correlated with total content of phenols in the samples. Thus, Deschampsia antarctica Desv. plants are a valuable source of natural phenolic antioxidants, and the most common antioxidants in the extracts are orientin, orientin 2"-O-beta-arabinopyranoside and isoswertia-japonin 2"-O-beta-arabinopyranoside.

Utilization of the second-most abundant biopolymer, lignin, in production of fine chemicals is considered as a strategy for environmental conservation and economic feasibility of technologies. Photocatalytic conversion of sodium lignosulfonate to low molecular weight compounds over eco-friendly semiconducting materials under simulated solar light is a perspective eco-innovative approach for “green technology” development. The more efficient depolymerization of lignosulfonate during photolytic reaction occurs at pH 2 as a result of sulfonic groups’ protonation, whereas the re-polymerization of hydrolyzed fragments to more complex structure in solutions at pH 5 and pH 9 is reported. Photo-sensibilization pathway toward polymer fragmentation is low effective process. It is shown that photocatalytic process is also more effective at pH 2 due to an electrostatic interaction of positively charge surface of metal oxides’ films and negatively charged NaLSA molecules. As shown by LDI MS investigation, the destruction of aromatic component of NaLSA molecule can be achieved in the presence of TiO2 film under simulated solar light due to the strong reductive power of superoxide radicals resulting in the benzoic ring-opening route. The mechanism of photocatalytic reaction over iron titanate films is governed by the presence of two semi-conductive crystalline phases, pseudobrookite and landauite, that are characterized by the anodically shifted energy positions of the conduction and valence bands compared to TiO2 providing an effective oxidation by HO• radicals. Nitrogen-doped iron titanate films are considered as a photocatalyst for the processes of low molecular weight aromatic compounds’ synthesis exhibiting activity under both simulated solar and visible light with the phenol yields of 0.96 μg mL−1 and 1.2 μg mL−1, respectively.

Досліджено склад і антиоксидантні властивості екстрактів, вилучених із рослин Deschampsia antarc tica É. Desv., зібраних у регіоні Аргентинських островів — півострова Київ (Морська Антарктика).. Склад екстрактів вивчено методами високоефективної рідинної хроматографії та мас-спектрометрії з матрично- активованою лазерною десорбцією/іонізацією; антиоксидантні властивості досліджено методом Фоліна— Чокальтеу та DPPH-тесту. Встановлено, що основними класами речовин, які містяться в екстрактах, є поліфенольні сполуки, зокрема флавоноїди, гідроксикоричні та гідроксибензойні кислоти. Підтверджено, що флавоноїди переважно представлені глікозидами лютеоліну; склад та кількість фенольних сполук залежить від генотипу рослини, місця походження та умов навколишнього середовища. Виявлено, що загальний вміст поліфенолів у досліджених екстрактах знаходиться в діапазоні 4, 33—10, 93 мг/г сирої сировини; найбільшу кількість активних речовин містять екстракти, вилучені з рослин острова Україна, а найменшу — з острова Дарбу. Результати антиоксидантних досліджень показали, що екстракти виявляють високу антирадикальну активність і здатні за 60 хв інгібувати понад 50 % DPPH радикалів. Одержані дані щодо складу поліфенолів у рослинах Deschampsia antarctica É. Desv. Можуть слугувати маркером для моніторингу кліматичних змін.

З використанням двох різних процедур екстракції одержано вісім етанольних екстрактів із листя рослин Magnolia X soulangeana Soul.-Bod., Magnolia kobus та двох зразків Camellia japonica L. За допомогою високо- ефективної рідинної хроматографії, методу Фоліна—Чокальтеу і DPPH тесту вивчено склад та анти- оксидантні властивості одержаних екстрактів. Показано, що основними складовими екстрактів магнолій є глікозиди кверцетину та похідні оксикоричних кислот, тоді як у екстрактах камелій переважають катехі- ни і похідні оксибензойних кислот. Склад екстрактів залежить не тільки від виду рослини, а й від способу екстрагування; загалом, екстракти, одержані при температурі 60 °C та під дією ультразвуку, мають біль- ший вміст поліфенолів, ніж екстракти, отримані кип’ятінням рослинного матеріалу у 70 %-му етанолі при ~85 °C ; загальна кількість фенольних сполук у екстрактах змінювалась у діапазоні 50—150 мг/л. Виявлено, що, попри значну різницю у вмісті фенолів, всі екстракти мають дуже високу антиоксидантну актив- ність як у тесті Фоліна—Чокальтеу, так і в реакції з DPPH радикалами. Показано, що екстракти мають загальний фенольний індекс 1,5—7,5, а протягом 30 хв реакції сім з восьми екстрактів інгібують понад 50 % радикалів DPPH навіть після розведення у 10 разів. Екстракт камелії з найвищими антиоксидантними властивостями було протестовано як добавку до біодизелю, що має запобігти його окисненню під час збе- рігання. Стабільність біодизелю, одержаного з Camelina sativa (L.) Crantz, досліджували за прискореною процедурою при 43 °C протягом чотирьох тижнів, критерієм окиснення біопалива слугувало його кислотне число. Попередні результати показали, що екстракт камелії може бути ефективним антиоксидантним агентом — запобіжником окиснення біодизелю.

The adsorption of phenol by activated carbons obtained by the alkaline thermolysis (KOH, 800°C) of fossil coals of various degrees of metamorphism (Cdaf = 70.4–95.6%) was studied. Kinetic dependences and adsorption isotherms were obtained at initial concentrations of ≤3 mg/cm3 (25°C). The rate constants of absorption of the adsorbate, maximum and specific capacities for phenol, and their dependences on Cdaf were determined. The main processes of the interaction of phenol with surface adsorption centers are discussed.

Aim. To obtain a plant tissue culture of S. baicalensis as a possible source of biologically active compounds (BAC) with a wide range of pharmacological action. Methods. Plant tissue culture, photocolorimetric method, reversed-phase high performance liquid chromatography (HPLC) method. Results. Two stably productive plant tissue culture strains (16SB3 and 20SB4) of S. baicalensis were obtained from fragments of roots seedling on a specially developed agar nutrient medium 5С01. The yield of dry biomass from 1 liter of this medium per passage (21st day of growth) for strain 16SB3 is 25–30 g, for strain 20SB4 – 30–40 g. The total content of flavonoids in dry biomass was in terms of routine for strains 16SB3 and 20SB4 – 0.6–0.9 and 0.7–0.9 mg/g, respectively, and the yield of flavonoids – 18–27 and 21–36 mg/l of nutrient medium, respectively. BAC typical for plants in nature, in particular, flavonoids vogonin, baikalein, neobaikalein, skulkapfavon and their derivatives, were found in the studied biomass of both strains. Conclusions. It was found that the biomass of the two strains of S. baicalensis plant tissue culture accumulated the same BAC, in particular, flavonoids, as do plants in natural conditions. The resulting plant tissue culture is promising as a possible source of Baikal skullcap BAC.

Sulfonylation of gossypol with stepwise increase of tosyl chloride content in the presence of 4-methoxypyridine N-oxide and triethylamine was carried out. The sequence of gossypol's hydroxyl groups tosylation was studied using HPLC, FT-IR and UV-Vis spectroscopy. It was shown that 4-methoxypyridine N-oxide is a much more effective catalyst compared to triethylamine, and its use allows to selectively tosylate gossypol to 7,7'-ditosyloxygossypol. The structure and tautomeric equilibria of obtained 7,7'- ditosyloxygossypol in dichloromethane were studied using FT-IR, UV-Vis, H-1, C-13 and H-1-H-1 COSY NMR, Mass spectroscopy, and quantum chemistry methods. It was found that dilactol tautomeric form is more preferable for 7,7'-ditosyloxygossypol in dichloromethane, contrary to gossypol. It was proven that the combined use of triethylamine and 4-methoxypyridine N-oxide allows to tosylate different hydroxyl groups of gossypol. (C) 2021 Elsevier B.V. All rights reserved.

The work was aimed at studying the phytochemicals available in D. antarctica plants from various sites on Antarctic Islands, introducing the plants into in vitro culture and comparing the extracts from the plants grown in situ and in vitro. All the extracts were found to contain high amount of phenols, with luteolin and hydroxybenzoic acids derivatives being the main phytochemicals in the extracts from the plants grown in situ and in vitro. Being diluted by 10 times, the extracts scavenged 50÷90% of DPPH• radicals, 20÷40% of NO• radicals and 40÷60% of OH• radicals. Despite the differences in composition, extracts from the plants grown in situ and in vitro showed similar radical scavenging activity.

Естери жирних кислот фітостеролів є перспективними харчовими добавками які знижують ризики розвитку хвороб серця. Відомо, що рослинні стерини, насамперед жирний естер ситостерину, знижують як холестерин в сироватці крові, так і холестерин ЛПНП, і є перспективними харчовими добавками для зниження ризику серцевих захворювань. Фітостероли, і більшою мірою фітостаноли, пригнічують всмоктування холестерину в кишечнику, самі не всмоктуючись при цьому у значних кількостях. В зв’язку з цим важливою задачею є розробка нових методів синтезу жирних естерів фітостеролів.

Останнім часом спостерігається підвищений інтерес наукової спільноти до природних антиоксидантів, сполук, що сповільняють чи припиняють процеси окиснення. Одними з таких антиоксидантів є потенційно біологічно активні імінопохідні природного поліфенолу – госиполу. В рамках продовження наших попередніх досліджень було синтезовано дві основи Шиффа госиполу (рис. 1) і за допомогою ІЧ та ПМР спектроскопії досліджено їхню будову і таутомерні форми.

The aim of the work was to identify the main components of orchid extracts and to study their interaction with silica. Composition of sixteen orchid extracts was investigated by means of high performance liquid chromatography and laser desorption/ionization mass spectrometry; as it was shown in this study, flavonoids and phenolic acids were the main bioactive compounds available in the extracts. The interaction between various phenols and silica silanol groups was studied by quantum chemical method. Results show that the strength of interaction of phenols with silica increased in the following order: ferullic, feruloylquinic and fertaric acids< kaempferol, apingenin<< chlorogenic and caffeic acids, rhamnetin, quercetin, luteolin, epicatechin gallate. The common feature of compounds characterized by the strongest interaction with silanol groups is the presence of a phenol ring with two neighbouring hydroxyl groups. The hydrogen bonds formed between these groups and silanol groups are much shorter (about 0.17 nm) than those formed by other hydroxyl groups of phenols (up to 0.28 nm).