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1

Spin trapping studies of essential oils in lipid systems

Makarova K., Drązikowska K., Suska B., Zawada K., Wawer I.

Nukleonika

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2015

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Vol. 60, No. 3, part 1

461--468

EN

In the present work, we report the results of a spin trapping ESR study of four essential oils widely used for skin care products such as creams and bath salts. The studied essential oils are Rosmarini aetheroleum (rosemary), Menthae piperitae aetheroleum (mint), Lavandulae aetheroleum (lavender), and Thymi aetheroleum (thyme). Fenton reaction in the presence of ethanol was used to generate free radicals. The N-tert- -butyl-α-phenylnitrone (PBN) was used as a spin trap. In the Fenton reaction, the rosemary oil had the lowest effect on radical adduct formation as compared to the reference Fenton system. Since essential oils are known to be lipid soluble, we also conducted studies of essential oils in Fenton reaction in the presence of lipids. Two model lipids were used, namely 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dipalmitoyl-sn- -glycero-3-phosphocholine (DPPC). The obtained results suggested that in the presence of DOPC lipids, the •OH and PBN/•CHCH3(OH) radicals are formed in both phases, that is, water and lipids, and all the studied essential oils affected the Fenton reaction in a similar way. Whereas, in the DPPC system, the additional type of PBN/X (aN = 16.1 G, aH = 2.9 G) radical adduct was generated. DFT calculations of hyperfi ne splittings were performed at B3LYP/6-311+G(d,p)/EPR-II level of theory for the set of c-centered PBN adducts in order to identify PBN/X radical.

2

Chemia i farmacja bliżej natury, czyli jak przedłużyć życie w zdrowiu

Wawer I.

Chemik

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2010

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Vol. 64, nr 4

219-227

PL

Nowoczesna medycyna (personalna, żywieniowa) coraz bardziej zwraca uwagę na profilaktykę, na człowieka w środowisku, jego sposób życia i dietę. Zadaniem nauki jest troska o racjonalne wykorzystanie naturalnych zasobów. W świecie roślin znajdujemy mnóstwo związków cennych dla zdrowia, o właściwościach antyoksydacyjnych, są one nie tylko w roślinach leczniczych, ale też w jadalnych. Przemysł farmaceutyczny interesuje się związkami polifenolowymi, takimi jak flawonoidy czy kwasy hydroksycynamonowe. Mogą one stanowić wyjściowe struktury dla nowych leków przeciwzapalnych przeciwwirusowych, przeciwbakteryjnych czy przeciwnowotworowych. W artykule scharakteryzowano właściwości i potencjalne zastosowania takich związków, jak: resweratrol, kurkumina, oligomer proantocyjanidyny, galusan epigalokatechiny, kwas rozmarynowy i chlorogenowy, betainy i antocyjaniny, zachęcając do opracowania metod syntezy i poszukiwania bioaktywnych pochodnych.

EN

Modern medicine (especially personalised and nutritional approach) focuses more attention on the diet, life style and the environment. Scientists have to examine more closely what we are eating, how diseases can be treated more rationally, and how we can more effectively use our natural resources. The pharmaceutical industry is searching for new medical plants, the functional compounds of which can serve as a starting point for the development of new drugs. Health-beneficial and life-prolonging effects of polyphenols are accompanied by the stimulation of various maintenance mechanisms, including protection against free-radical and oxidation-induced damage. These natural compounds are promising anti-inflammatory, antiviral, antibacterial and anticancer agents. The representatives of polyphenols: resveratrol, epigallocatechin-gallate, curcumin, proanthocyanidin, chlorogenic acid and rosemarinic acid, betalain, anthocyans are characterised as potential candidates for drugs. This review provides some information and serves to encourage work (chemical synthesis) in the field of flavonoids.

3

Structural Studies of 1-Aryl-2-aminoimidazolinium Bromides: Focus on Tautomer Preference of the 2-Aminoimidazoline Moiety in the Solid State

Dobrowolski M., Cyrański M., Pisklak M., Wawer I., Matosiuk D.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 5-6

1037-1048

EN

The crystal structures of five 1-(4-X-phenyl)-2-aminoimidazolinium bromides (where X = -OCH3, -CH3, -H, -Cl and -NO2) were determined by X-ray crystallography with the aim to investigate the tautomer preference of the aminoimidazoline moiety in the solid state. The molecular structures clearly indicate that only the ring nitrogen is protonated. The crystals are stabilized by interactions between the hydrogens of the amino group (also NH fragment of the imidazoline ring) and bromide anion. In the case of the nitro derivative additional strong hydrogen bonds are a consequence of the presence of water molecule in the crystal lattice. The methoxy and nitro derivatives were studied by 15N CP/MAS NMR and the analysis of the tautomer preference was completed by ab initio calculations at the B3LYP/6-311+G** level.

4

NMR ciała stałego : zastosowania w farmacji i diagnostyce medycznej

Wawer I., Pisklak M., Paradowska K.

Wiadomości Chemiczne

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2005

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[Z] 59, 1-2

121--137

EN

Some characteristic features, distinguishing NMR in solution and solid phase, are briefly described. The techniques of magic angle spinning, cross-polarization, as well as the experiments with variable cross-polarization time and dipolar-dephasing pulse sequences are illustrated. The spectra measured for solutions are frequently used as an aid in the assignment of solid-state ones. The differences Δ=δsolution-δsolid state are explained in terms of conformational effects (resulting from frozen intramolecular reorientation in the solids) and intra- and intermolecular interactions (hydrogen bonds and also short intermolecular contacts in the crystals). Solid-state NMR spectroscopy has become an important technique in the field of pharmaceutical sciences. Solid-state techniques are used for the characterization of pharmaceutical solids: drug substances and dosage forms (tablets) and their mutual interactions. Structural information on solid antibiotics (penicillin salts, erythromycin A, chloramphenicol and its derivatives), anticoagulants (warfarin, sintrom), antimalaria (artemizinin) or anxiolytic drugs (buspirone and its analogues) was obtained by the analysis of 13C CP MAS spectra. Frequently exploited area is polymorphism because pharmaceutical polymorphs can display different solubilities, dissolution rates and bioavailability. Polymorphic forms of steroids (testosterone, prednisolone, cortisone) and 4-azasteroids (finasteride) and of numerous other drugs (e.g. AZT, paracetamol, phenobarbital) have been detected. Solid-state NMR has thus an ability to differentiate polymorphs, determine asymmetry in the crystal unit cell and investigate molecular motions within the solids. MAS NMR spectra can be recorded for powdered tablets, enabling fast identification of the active substance. Few examples of forensic applications include "Extasy" and Viagra tablets. The technique ideally lends itself to the studies on drugexcipients interaction, possible conversions of the drug during processing and storage can be followed. Multinuclear solid state NMR is also useful in characterization of materials and tissues removed during surgery (bones, brain tumors, urinary stones).

5

1H, 13C, and 15N NMR Study of Nitrosoureido Sugars, Derivatives of 2-Amino-2-deoxy-beta=D-glucopyranoside and Amino Acids or Peptides

Wawer I., Weychert M., Piekarska-Bartoszewicz B., Temeriusz A.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 8

1127-1136

EN

Nitrosoureido sugars with amino acid and dipeptide ester residue were characterized by 1H, 13C and 15N NMR and their spectra were assigned using 1D and 2D NMR methods. The N-nitrosation of ureido sugars frequently yields a mixture of isomers. In the case of ureido sugars with amino acid residues preferably the N3-NO isomers were obtained, whereas for compounds with dipeptide esters the N1-NO isomers dominate. The results are in agreement with the molecular modelling (PM3) predictions, when the intramolecular hydrogen bonds, net charges at nitrogen atoms and heat of formations of particular isomers are considered.

6

Structure and Hydrogen Bonding of Solid N1-Alkyl-N2-(2-hydroxy, 4- or 5-methylphenyl)thioureas

Wawer I., Anulewicz-Ostrowska R., Maciejewska D., Koleva V.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 6

823-835

EN

Crystalline N1-alkyl-N2-arylthioureas with ortho hydroxyl and para or meta methyl substituents to the phenyl ring were studied by single crystal X-ray diffraction, IR and solid state 13C cP MAS NMR. Two different modes of association were found: i) intermolecular N1H...S bonds and N2H not involved in hydrogen bonding in N1-methyl-N2-(2-hydroxy, 5-metylphenyl)thuiourea 1, ii) cyclic dimers with two N2H...S hydrogen bonds (S...N2 distance of 3.332 A) and N1H engaged in intermolecular N1H...O bond in N1-methyl-N2-(2-hydroxy,4 methylphenyl)thiourea 2. Changes of carbon chemical shifts between solution and solid state result mainly from the reorientation of the aromatic ring with respect to the thiourea fragent.

7

Synthesis and NMR study of N,N'-bis(methyl 3,4,6-tri-O-acetyl-2-deoxy-B-D-glucopyranosid-2-yl)urea and its N'-nitroso derivative

Temeriusz A., Piekarska-Bartoszewicz B., Weychert M., Wawer I.

Polish Journal of Chemistry

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1999

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vol. 73 nr 6

1011-1018

EN

N,N'-Bis(methyl 3,4,6-tri-O-acetyl-2-deoxy-b-D-glucopyranosid-2-yl)urea 1 and its N'-nitroso derivative 2 were synthesized from methyl 2-amino-3,4,6-tri-O-acetyl-2-deoxy-b-D-glucopyranoside and di(4-nitrophenyl)carbamate. The nitrosation was carried out using N2O3 in dichloromethane. The structure of compounds was analyzed by 1H, 13C, 15N NMR in CDCl3 and 13C CP MAS in the solid state. The assignments of resonances were done by COSY1H, 13C, HETCOR and the 1H, 15N2D correlation spectroscopy. Compound 1 gives one set of 1H/13C resonances in solution, but exhibits polymorphism in the solid state.

8

(13)C CP MAS NMR study of some 4,4'-disubstituted-trans-azobenzenes

Maciejewska D., Koleva V., Wawer I.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 12

2531-2536

EN

Azobenzenes with para-dimethylamino group at aromatic ring and various para substitutes to another phenyl have been studied by (13)C CP MAS NMR spetroscopy followed by semi-empirical AMI MO calculations. The locked trans-configuration around N=N bond in the state results in non-equivalence of ortho carbons (C2 and C6, also C2' and C6') and the diference in chemical shifts is 12.9-22.0 ppm. The separation of meta carbons resonances is less manifested but in 1, 3, 4, 8 the non-equivalence of C3' and C5' is enhanced by the orientation of X-substituents at C4'.

9

Conformational temperature effects in deacetylcephalothin investigated by experimental and simulated H NMR

Zimniak A., Oszczapowicz I., Sikora A., Wawer I.

Bulletin of the Polish Academy of Sciences. Chemistry

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1998

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Vol. 46, No. 2

179-183

EN

Temperature-dependent difference between chemical shifts in AB proton system due to the conformational transition have been observed in cephalosporin deacetylcephalothin. To exclude the possibility of the dynamic process the experimental and simulated spectra were compared.