На сайте журнала Journal of Ethnopharmacology   (IF=3,414) опубликована статья  с участием сотрудников Института Е.Е. Шульц, Т.Н. Петровой, Т.В. Рыбаловой, Т.С. Фроловой

Chromones and coumarins from Saposhnikovia divaricata (Turcz.) Schischk. Growing in Buryatia and Mongolia and their cytotoxicity

Journal of Ethnopharmacology, Available online 10 January 2020, 112517

Abstract

Ethnopharmacological relevance

Saposhnikovia divaricata (family Apiaceae) a traditional medicinal plant distributed in many provinces of China, is well known for the pharmaceutical value and has been used for rheumatic arthritis, and anxiety in children. Antiviral, antioxidant and antiproliferative activities were also mentioned. The application of this plant are recorded in the Chinese Medicine (CM) classical text the Shen Nong's Materia Medica (Shen Nong Ben Cao Jing). In this monograph S. divaricata (syn RadixLedebouriella divaricata) is graded as a premium-grade herb, with their broad-spectrum of therapeutic applications for the treatment of cough, common cold, arthralgia, as well as in rheumatic disorders.

Aim of the study

To isolate and identify chemical constituents (chromones and coumarins) from S. divaricata, collected in Buryatia and Mongolia and to study their in vitro anticancer activity against MEL-8, U-937, DU-145, MDA-MB-231 and ВТ-474 cell lines.

Materials and methods

An 40% aqueous ethanol extract of the roots of S. divaricata was prepared and further successively fractionated by extraction with petroleum ether, diethyl ether,tert-butyl methyl ether and ethyl acetate. The obtained extracts were subjected to a series of chromatographic separations on silica gel for isolation of individual compounds. Isolated compounds were tested for their cytotoxicity with respect to model cancer cell lines using the conventional MTT assays. Results: Total of 15 individual compounds: coumarins scopoletin 2, bergapten 3, isoimperatorin 4, marmesin 5, (+)-decursinol 9, (−)-praeruptorin B 10, oxypeucedanin hydrate 11, chromones: hamaudol 6, cimifugin 7, 5-О-methylvisamminol 8, chromone glycosides: prim-O-glucosylcimifugin 12, sec-O-glucosylhamaudol 13, 4′-O-β-D-glucopyranosyl-5-О-methylvisamminol 14, 4′-O-β-D-glucopyranosylvisamminol (15) and also polyyne compound panaxinol 1 were isolated and characterized. The structure of dihydropyranocoumarin 10 was confirmed by X-ray diffraction analyses. HPLC-UV method was used for determination of the content of most abundant chromones 7, 12 and 14 in the roots of S. divaricata, collected in Mongolia. Compounds 3–11 and 13, 14 were evaluated for their cytotoxicity with respect to model cancer cell lines. All the compounds were non-toxic in the hemolysis test. Conclusion: This report about the phytochemical profiles of S. divaricata growing in Mongolia and Buryatia led to the identification of 14 compounds including coumarins and chromones. The available coumarins and chromones may serve as new leads for the discovery of anticancer drugs.

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На сайте журнала Dalton Transactions (IF 4,052) опубликована статья с участием сотрудников Института   д.х.н. И.И. Олейника (внс ЛЭАСМ), к.х.н. И.В. Олейник (снс ЛЭАСМ):

Probing the effect of ortho-cycloalkyl ring size on activity and thermostability in cycloheptyl-fused N,N,N-iron ethylene polymerization catalysts

Abstract

The syntheses of six bis(imino)-5,6,7,8-tetrahydrocycloheptapyridine-iron(II) chloride complexes, [2-{(Ar)NCMe}-9-{N(Ar)}C₁₀H₁₀N]FeCl₂ (Ar = 2-(C₅H₉)-6-MeC₆H₃Fe1, 2-(C₆H₁₁)-6-MeC₆H₃Fe2, 2-(C₈H₁₅)-6-MeC₆H₃Fe3, 2-(C₅H₉)-4,6-Me₂C₆H₂Fe4, 2-(C_{6H11)-4,6-Me2C6H2Fe5, 2-(C8H15)-4,6-Me2C6H3 Fe6), are reported in which the ring size of the ortho-cycloalkyl group has been varied as has the type of para-substituent. The molecular structures of Fe3 and Fe6 reveal square pyramidal geometries at iron while the ortho-cyclooctyl rings adopt boat-chair conformations. On treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all six complexes showed optimal activities at 80 °C [up to 1.9 × 10⁷ g of PE per mol Fe per h for Fe5/MMAO] for ethylene polymerization forming linear polyethylene (Tm's > 126 °C). Notably, the catalytic activities showed a marked correlation with the ring size of the ortho-cycloalkyl substituent: cyclohexyl (Fe2 and Fe5) > cyclooctyl (Fe3 and Fe6) > cyclopentyl (Fe1 and Fe4) for either para-substituent, H or Me. Furthermore, this family of iron catalysts exhibited remarkable thermostability by remaining highly active even at temperatures as high as 100 °C (1.1 × 10⁷ g of PE per mol Fe per h); the wide variation in polymer molecular weights (Mw: 2.4–166 kg mol⁻¹), influenced through choice of precatalyst and co-catalyst as well as by temperature and pressure, further highlights the versatility of these catalysts.}

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На сайте журнала Computational and Structural Biotechnology Journal (IF 4,72) опубликован мини-обзор с участием сотрудника Института   к.х.н. А.Ю. Воробьев (снс ЛФ):

Long-wavelength photoremovable protecting groups: On the way to in vivo application

Abstract

Photoremovable protective groups (PPGs) and related “caged” compounds have been recognized as a powerful tool in an arsenal of life science methods. The present review is focused on recent advances in design of “caged” compounds which function in red or near-infrared region. The naive comparison of photon energy with that of organic bond leads to the illusion that long-wavelength activation is possible only for weak chemical bonds like N-N. However, there are different means to overcome this threshold and shift the uncaging functionality into red or near-infrared regions for general organic bonds. We overview these strategies, including the novel photochemical and photophysical mechanisms used in newly developed PPGs, singlet-oxygen-mediated photolysis, and two-photon absorption. Recent advances in science places the infrared-sensitive PPGs to the same usability level as traditional ones, facilitating in vivo application of caged compounds.

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В журнале Dalton Transactions (IF 4,052) опубликована статья с участием сотрудника Института   И.П. Коскина (мнс, ЛОЭ):

Defect induced photoluminescence and triboluminescence in layered CaLaAl₃O₇

Abstract

In this work, a layered melilite structure, CaLaAl₃O₇, was synthesized and observed to have obvious luminescence behaviors under the stimuli of ultraviolet light and rubbing, which were called photoluminescence and triboluminescence, respectively. Considering the wide bandgap of CaLaAl₃O₇ and its specific crystal structure, the observed luminescence should be attributed to intrinsic defects. Both the photoluminescence and triboluminescence of CaLaAl₃O₇> show a strong dependence on the synthesis atmosphere, suggesting that they should be related to the oxygen vacancy. It is attractive to find that the triboluminescence of CaLaAl₃O₇ shows a distinct spectral characteristic compared to its photoluminescence. Further computational results suggest that the applied mechanical stimuli on the CaLaAl₃O₇ cell could promote the formation of the vacancies of oxygen and calcium, responsible for the spectral differences.

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The Diels–Alder Reaction for the Synthesis of Polycyclic Aromatic Compounds

Abstract

Polycyclic aromatic compounds (PACs) represent a class of molecules consisting of two or more condensed aromatic rings. They are currently of great interest as potential semiconducting materials for organic field‐effect transistors, light‐emitting diodes, and solar panels. Substituted PACs are not always readily available and may require complicated multi‐step synthetic procedures to be obtained. One of the promising methods of the synthesis of functionalized PACs is the assembly of polycyclic backbones from substituted building blocks via cycloaddition reactions, in particular, the Diels–Alder reaction. In this minireview we aimed to cover the recent progress in the application of the Diels–Alder reaction in PACs synthesis with the emphasis on the structures of dienophiles. While quinones and arynes still act most frequently as the dienophilic components, other dienophiles with activated double and triple carbon–carbon bonds attract attention due to the ability of insertion of functional groups into polycyclic structures. In the recent decade variants of Dehydro Diels–Alder reaction, especially HexaDehydro Diels–Alder reaction (HDDA) attract much attention leading to the formation of polycyclic structures in a single step. The present review covers mostly papers published during the past decade; older works are referenced only when it is necessary for the understanding of the results discussed.

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На сайте журнала Nucleic Acids Research (IF 11,147I) опубликована статья с участием сотрудников Института  :

Exploring the interactions of short RNAs with the human 40S ribosomal subunit near the mRNA entry site by EPR spectroscopy

Abstract

The features of previously unexplored labile complexes of human 40S ribosomal subunits with RNAs, whose formation is manifested in the cross-linking of aldehyde derivatives of RNAs to the ribosomal protein uS3 through its peptide 55–64 located outside the mRNA channel, were studied by EPR spectroscopy methods. Analysis of subatomic 40S subunit models showed that a likely site for labile RNA binding is a cluster of positively charged amino acid residues between the mRNA entry site and uS3 peptide 55–64. This is consistent with our finding that the 3′-terminal mRNA fragment hanging outside the 40S subunit prevents the cross-linking of an RNA derivative to this peptide. To detect labile complexes of 40S subunits with RNA by DEER/PELDOR spectroscopy, an undecaribonucleotide derivative with nitroxide spin labels at terminal nucleotides was utilized. We demonstrated that the 40S subunit channel occupancy with mRNA does not affect the RNA derivative binding and that uS3 peptide 55–64 is not involved in binding interactions. Replacing the RNA derivative with a DNA one revealed the importance of ribose 2′-OH groups for the complex formation. Using the single-label RNA derivatives, the distance between the mRNA entry site and the loosely bound RNA site on the 40S subunit was estimated.

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В журнале ACS Chemical Neuroscience   (IF 3,861) опубликована статья с участием сотрудников Института: к.х.н.О.В. Ардашова (снс ЛФАВ), к.б.н. А.В. Павловой (нс ЛФИ), к.б.н. Е.А. Морозовой (снс ЛФИ) , к.х.н. Д.В. Корчагиной (нс ГЯМР), Г.Е. Сальникова (снс, ГЯМР), к.х.н. А.М. Генаева (снс ЛМР), к.х.н. О.С. Патрушевой (нс ЛФАВ), Н. С. Ли-Жуланова (мнс ЛНТПС), д.б.н. Т.Г. Толстиковой (завлаб ЛФИ), д.х.н. К.П. Волчо (гнс ЛФАВ), д.х.н. Н.Ф. Салахутдинова (зав отделм ОМХ)

A Novel Small Molecule Supports the Survival of Cultured Dopamine Neurons and May Restore the Dopaminergic Innervation of the Brain in the MPTP Mouse Model of Parkinson’s Disease

Abstract

We previously showed that monoterpenoid (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol 1 alleviates motor manifestations of Parkinson’s disease in animal models. In the present study, we designed and synthesized monoepoxides of (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol 1 and evaluated their biological activity in the MPTP mouse model of Parkinson’s disease. We also assessed the ability of these compounds to penetrate the blood–brain barrier (BBB). According to these data, we chose epoxide 4, which potently restored the locomotor activity in MPTP-treated mice and efficiently penetrated the BBB, to further explore its potential mechanism of action. Epoxide 4 was found to robustly promote the survival of cultured dopamine neurons, protect dopamine neurons against toxin-induced degeneration, and trigger the mitogen-activated protein kinase (MAPK) signaling cascade in cells of neuronal origin. Meanwhile, neither the survival-promoting effect nor MAPK activation was observed in non-neuronal cells treated with epoxide 4. In the MPTP mouse model of Parkinson’s disease, compound 4 increased the density of dopamine neuron fibers in the striatum, which can highlight its potential to stimulate striatal reinnervation and thus halt disease progression. Taken together, these data indicate that epoxide 4 can be a promising compound for further development, not only as a symptomatic but also as a neuroprotective and neurorestorative drug for Parkinson’s disease.

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На сайте журнала Journal of Catalysis, 2019, Volume 380, December 2019, Pages 145-152   (IF 7,723) опубликована статья с участием сотрудников Института: к.х.н. И.В. Ильиной (снс, ЛФАВ),  к.х.н. Д.В. Корчагиной (снс ГЯМР), д.х.н. Ю.В. Гатилова (внс , ГРСА), д.х.н., проф. РАН К.П. Волчо (гнс ЛФАВ),  д.х.н., проф. Н.Ф. Салахутдинова (зав.отделом медицинской химии)

Clay nanotubes catalyzed solvent-free synthesis of octahydro-2H-chromenols with pharmaceutical potential from (-)-isopulegol and ketones

Abstract

Natural halloysite nanotubes (HNT) pretreated with hydrochloric acid were applied for the first time for selective synthesis of octahydro-2H-chromenols (as 4R- and 4S-diastereomers) using terpenoid (-)-isopulegol and ketones as reactants. The main attention was paid to the reaction with acetone, because the resulting 4R-isomer displays antiviral activity. While the drawback of the isopulegol Prins reaction with ketones is a low yield of chromenols, considerably higher values could be achieved using a halloysite catalyst under solvent-free conditions and low temperature (30 °C) giving up to 77% overall selectivity towards chromenols. The isolated yield of the acetone-derived 4R-isomer was 66%, significantly exceeding previous results. The proposed mechanism of isopulegol condensation with ketones is more complex than in the case of aldehydes. Formation of the target chromenols occurs through addition of water to the cyclic intermediate. In parallel interactions of this intermediate with isopulegol lead to stereoselective formation of an ester with the chromene structure, which after hydrolysis gives chromenols. Formation of the ether is opposite to the Prins reaction of aliphatic alcohols with carbonyl compounds, where non-cyclic acetals are typically formed. This clearly confirms that in the Prins reaction of isopulegol with carbonyl compounds, the cyclic intermediate plays a key role. A decrease in the halloysite hydration led to an increase in ether selectivity, while with the increase in the studied catalysts acidity, formation of dehydration by-products increased. A reaction scheme for the products formation was proposed and evaluated by kinetic modelling. A possibility of the catalyst reuse has been also shown. Halloysite nanotubes can be considered as highly selective, eco-friendly, low-cost and reusable catalysts for synthesis of heterocycles based on terpenoids and ketones.

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На сайте журнала The Journal of Physical Chemistry C, 2019, 123, 46, 28058-28065   (IF 4,309) опубликована статья с участием сотрудницы Института: д.х.н. Л.В. Щеголевой (внс, ЛЭАСМ)

Magnetic Resonance Characteristics of Negative Polarons in Neat Poly(3-hexyl-thiophene)

Abstract

Magnetic resonance characteristics of carriers of both electron spin and electric charge (polarons) in conjugated polymers are required for a deeper understanding of properties of these semiconducting materials. In poly(3-hexyl-thiophene), P3HT, which is an important material for photovoltaic applications, such information is available only for positive polarons, which are readily generated in the presence of electron acceptors via photoinduced processes. Influence of an external magnetic field on X-ray-induced delayed fluorescence from undoped P3HT and its solutions allowed us to visualize the spin interactions in the primary polaron pairs and to estimate the g-tensor components (g_⊥≈ 2.0023, g_|| ≈ 2.008) for the negative charge carriers in P3HT molecules. There is evidence that in neat regioregular P3HT the g-tensor anisotropy for the polarons, migrating along polymer chains, is averaged partially due to irregularities in the polymer structure.

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В журнале CrystEngComm, 2019, V. 21, N 39, Pp 5931-5946   (IF 3,382) опубликована статья с участием сотрудников Института  к.х.н. Т.А. Вагановой (снс ЛГетС), д.х.н. Ю.В. Гатилова (внс, руководитель группы ГРСА), к.х.н. И.П. Чуйкова (нс ЛМР) и д.х.н. Е.В. Малыхина (гнс ЛГетС)

Impact of molecular packing rearrangement on solid-state fluorescence: polyhalogenated N-hetarylamines vs. their co-crystals with 18-crown-6

Abstract

A series of polyhalogenated hetarylamines and their co-crystals with 18-crown-6 ether was used to reveal the effect of co-crystallization on the supramolecular structure and fluorescence properties as well as the relationship between these characteristics and peculiarities of the hetarylamine chemical structure (α- or γ-position of the NH₂ group, number of Cl and F substituents, pyridine or quinoline framework, presence of a fluorophore fragment). Incorporation of crown ether into the crystal matrix of the hetarylamine results in a significant rearrangement of the supramolecular structure. In all cases, the N–H⋯N_het and N–H⋯F H-bonds are replaced by the N–H⋯O_crown bond. Changes in π-electron interactions that affect fluorescence characteristics depend on the amine structure. In the co-crystals of γ-aminopyridines, replacement of C–F⋯π_F interactions with π_F⋯π_F stacking causes the fluorescence quenching or a bathochromic shift of λ_em, whereas replacement of π_F⋯π_F or π_F⋯π_H stacking with C–F⋯π_F interactions or π_H⋯πH stacking in the co-crystals of α-aminopyridines is accompanied by the hypsochromic shift of λ_em. γ-Aminopyridines show more pronounced changes in fluorescence characteristics as compared to α-aminopyridines, the effect being dependent on the nature of the halogen substituents. The fluorescence properties of aminoquinolines, regardless of the amino group location, are insignificantly modified due to the ability of the extended π-system to minimize interaction changes. Exploration of the nature of the excited states of isolated molecules, homocrystals and co-crystals using quantum mechanical calculations evidences that fluorescence quenching occurs due to EET, facilitated by the presence of crown ether molecules. The bathochromic and hypsochromic shifts of emission are caused by the change in a mutual orientation of the hetarylamine molecules with subsequent different stabilization of the ground and excited states. Using DSC, the co-crystals' supramolecular structure was found to self-organize from solution or melt and to regenerate in the melting–crystallization cycle. The revealed modification of the hetarylamines' fluorescence properties due to the formation of co-crystals with crown ether seems to be promising for use in solid-state supramolecular chemo and thermo sensors (indicators).

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