Flavonoidi iz cvetova Cephalaria pastricensis i njihova antiradikalska aktivnost

Two flavonoid glycosides 1 and 2 having the luteolin structure were isolated from flowers of the endemic plant species Cephalaria pastricensis. They were identified by (1)H and (13)C NMR, as well as UV/Vis spectroscopy. The structures of 1 and 2 were also confirmed by the spectral data of aglycones and TLC of the sugars obtained after acid hydrolysis. Flavones 1 and 2 showed significant antiradical activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay.Iz cvetova Cephalaria pastricensis izolovana su dva heterozidna flavonoida sa luteolinskim aglikonom (1 i 2). Wihova struktura je određena primenom 1H i 13C-NMR i UV spektroskopije. Strukture flavona 1 i 2 su potvrđene i spektrima aglikona, odnosno tankoslojnom hromatografijom oslobođenih šećera nakon kisele hidrolize. Jedinjenja 1 i 2 su pokazala značajnu antiradikalsku aktivnost u 1,1-difenil-2 pikrilhidrazil (DPPH) testu

Complex conductivity of soils

The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz to 45 kHz. The soil samples are saturated with six different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m21, NaCl, 258C) in order to determine their intrinsic formation factor and surface conductivity. This data set is used to test the predictions of the dynamic Stern polarization model of porous media in terms of relationship between the quadrature conductivity and the surface conductivity. We also investigate the relationship between the normalized chargeability (the difference of in-phase conductivity between two frequencies) and the quadrature conductivity at the geometric mean frequency. This data set confirms the relationships between the surface conductivity, the quadrature conductivity, and the normalized chargeability. The normalized chargeability depends linearly on the cation exchange capacity and specific surface area while the chargeability shows no dependence on these parameters. These new data and the dynamic Stern layer polarization model are observed to be mutually consistent. Traditionally, in hydrogeophysics, surface conductivity is neglected in the analysis of resistivity data. The relationships we have developed can be used in field conditions to avoid neglecting surface conductivity in the interpretation of DC resistivity tomograms. We also investigate the effects of temperature and saturation and, here again, the dynamic Stern layer predictions and the experimental observations are mutually consistent

Quaternary glacial history of the Mediterranean mountains

Glacial and periglacial landforms are widespread in the mountains of the Mediterranean region. The evidence for glacial and periglacial activity has been studied for over 120 years and it is possible to identify three phases of development in this area of research. First, a pioneer phase characterized by initial descriptive observations of glacial landforms; second, a mapping phase whereby the detailed distribution of glacial landforms and sediments have been depicted on geomorphological maps; and, third, an advanced phase characterized by detailed understanding of the geochronology of glacial sequences using radiometric dating alongside detailed sedimentological and stratigraphical analyses. It is only relatively recently that studies of glaciated mountain terrains in the Mediterranean region have reached an advanced phase and it is now clear from radiometric dating programmes that the Mediterranean mountains have been glaciated during multiple glacial cycles. The most extensive phases of glaciation appear to have occurred during the Middle Pleistocene. This represents a major shift from earlier work whereby many glacial sequences were assumed to have formed during the last cold stage. Glacial and periglacial deposits from multiple Quaternary cold stages constitute a valuable palaeoclimatic record. This is especially so in the Mediterranean mountains, since mountain glaciers in this latitudinal zone would have been particularly sensitive to changes in the global climate system. © 2006 Edward Arnold (Publishers) Ltd

Isogentisin (1,3-dihydroxy-7-methoxyxanthone)

The crystal structure of isogentisin, C14H10O5, a natural product isolated from Gentiana lutea, has been determined. The phenolic ring system is essentially planar and the displacement of the methoxy substituent from the mean molecular plane is very small. The structure is stabilized by a one-dimensional chain of intermolecular hydrogen bonds

Composition of the essential oil from roots and rhizomes of Valeriana pancicii Halácsy & Bald

The essential oil of subterranean parts of the endemic plant Valeriana pancicii was obtained by hydrodistillation and analysed by GC-MS. Plant material was collected in summer (sample A) and autumn (sample B) from the same location in Montenegro (Mountain Ljevorecki Kom). The main characteristic of V. pancicii essential oil was the low content of monoterpenoids and the high percentage of sesquiterpenoid compounds. The major compounds in the essential oil of both samples were patchouli alcohol, an unidentified oxygenated monoterpene, α-guaiene and γ-patchoulene. Copyright © 2002 John Wiley & Sons, Ltd

Parthenolide from the aerial parts of Tanacetum larvatum

The genus Tanacetum L. comprises ca 150 species that commonly occur in Europe from the Mediterranean to Persia. Tanacetum larvatum (Gris.) Kanitz, the examination of which is reported, is distributed on elevated rocky terrains in Albania, Serbia (Kosovo) and Montenegro. Aerial parts of T. larvatum were collected in Montenegro on two locations: crop a on mountain Komovi (altitutude 1800 m, 12 July 1998) and crop b on mountain Babji Zub (altitude ca 1500 m, 30 June 1999)

Sesquiterpene lactones from the aerial parts of Inula oculus-christi

Pulchellin E (1) and gaillardin (2) were isolated from the aerial parts of Inula oculus-christi, along with the flavone hispidulin. The C-13-NMR chemical shifts of 1 and 2 are reported. (C) 2003 Elsevier Science B.V. All rights reserved

Flavones and sesquiterpene lactones from Achillea atrata subsp multifida: Antimicrobial activity

Four flavones (1-4) and nine sesquiterpene lactones (5-13), one of them (5) a new compound, were isolated from the aerial parts of Achillea atrata L. subsp. multifida. Although the crude extract demonstrated in vitro inhibitory activity against Candida albicans and Bacillus subtilis, all isolated flavones were active against B. subtilis. Flavones 1, 2, and 3 were also active against C. albicans, while 1 and 3 exhibited activity against E. coli, as well. None of the tested lactones (7, 9, 12, and 13) showed any antimicrobial activity

Complete assignments of H-1 and C-13 NMR spectra of leucanthoside A, a new triterpenoid saponin from Cephalaria leucantha L.

Leucanthoside A, a new allose-containing triterpenoid saponin (1), was isolated from the aerial parts of Cephalaria leucantha L. Its structure was determined by electrospray ionization mass spectrometry and NMR spectroscopy. Complete assignments of the H-1 and 1 C NMR chemical shifts were achieved by two-dimensional NMR experiments: DQF-COSY, NOESY, TOCSY, HSQC, DINE-HSQC, HMBC, C-13-H-1 2D-J-resolved spectroscopy, and 1,1-ADEQUATE. Copyright (c) 2006 John Wiley & Sons, Ltd

Further sesquiterpene lactones from Anthemis carpatica

A new germacranolide, (E)-1 alpha, 10 beta-opoxy-3 beta-acetoxy-6 alpha-hydroxygermacra-4,11(13)-dien-12,8 alpha-oxide, together with nine new highly oxygenated guaiadien-12,6 alpha-olides of anthemolide, and cumambrin type were identified in the repealed examination of the aerial parts of the flowering Anthemis carpatica. In addition, six known guaianolides belonging to the same groups. also isolated previously from A. carpatica, along with two guaianolides, 2 beta-hydroxyepiligustrin and cumambrin B, not found before in this species, were isolated this time. (C) 2000 Elsevier Science Ltd. All rights reserved