Search results for "CONSTITUENTS"
showing 6 items of 26 documents
The first example of natural cyclic carbonate in terpenoids
2006
Abstract The first natural occurring cyclic carbonate terpenoid, the guaianolide hololeucin ( 1 ), was isolated from the aerial part of Centaurea hololeuca . Its structure was elucidated on the basis of extensive proton, 13 C and two-dimensional NMR experiments, as well as by transformation in its diacetyl derivative.
A New Algorithm for the Retrieval of Sun Induced Chlorophyll Fluorescence of Water Bodies Exploiting the Detailed Spectral Shape of Water-Leaving Rad…
2021
Sun induced chlorophyll fluorescence (SICF) emitted by phytoplankton provides considerable insights into the vital role of the carbon productivity of the earth’s aquatic ecosystems. However, the SICF signal leaving a water body is highly affected by the high spectral variability of its optically active constituents. To disentangle the SICF emission from the water-leaving radiance, a new high spectral resolution retrieval algorithm is presented, which significantly improves the fluorescence line height (FLH) method commonly used so far. The proposed algorithm retrieves the reflectance without SICF contribution by the extrapolation of the reflectance from the adjacent regions. Then, the SICF …
Chemical constituents from Phlomis bovei Noë and their chemotaxonomic significance
2020
Abstract A phytochemical investigation of the leaves and roots of Phlomis bovei Noe (Lamiaceae) led to the isolation of sixteen compounds, including iridoids (1, 2, 3), megastigmanes (4, 5), phenylpropanoids (6, 7, 8, 9, 10), lignans (11, 12, 13, 14), a nortriterpene (15), and a phenyl glucoside (16). Compounds (1, 2, 4, 5, 6, 10) were obtained from the leaves and compounds (1, 2, 3, 7, 8, 9, 11, 12, 13, 14, 15, 16) were isolated from the roots. Compounds 1 and 2 were found both in the leaves and in roots. The compounds were identified by analysis of 1D- (1H, 13C), 2D-NMR (1H–1H COSY, TOCSY, ROESY, HSQC, HMBC) spectroscopic data, mass spectrometry (ESI- and HR-ESI-MS), and by comparison wit…
Chemical Constituents of Urospermum picroides
1992
Seven phenolic compounds were isolated from the aerial parts of U. picroides. They were identified by UV spectra, TLC and HPLC-DAD as luteolin, luteolin-7-glucoside, quercetin, quercetin-3-galactoside, kaempferol-3-galactoside, chlorogenic and isochlorogenic acids. Other phenolics were characterized by HPLC-DAD analysis: gallic, protocatechuic, caffeic, ferulic and isoferulic acids, quercetin-3-glucoside and luteolin-4′-glucoside.
Un tipus especial d'oracions interrogatives: les interrogatives escindides
2014
This paper deals with the properties of interrogative sentences with a split constituent (or split interrogatives) in Catalan and Spanish. We compare split interrogatives with Wh-questions, yes/no questions, different kinds of confirmatory questions and clitic left dislocation constructions. Split interrogatives show a very clear-cut syntactic and phonological distinction between those constituents to be interpreted as shared or old information (theme) and the constituent which receives the focus of the sentence. Following recent theoretical work on the left periphery of the sentence, we propose that the Ground Phrase projection (placed below ForceP) is especially relevant in split interrog…
Invasive alien species – potential cheap resources of plant substances for medicinal use
2018
Some alien species demonstrate rather invasive behaviour. They have high tolerance of various habitat conditions and potent propagation ability. They not only over-compete the local vegetation but suppress the seed development of the native plants. In the newly invaded habitats they might not have suitable herbivores to control their populations. The only effective enemy might be Homo sapiens. Humans are known with their destructive power once an object has become significant for industrial utilization. The aim of this study is to review research data and reveal the potential of Ambrosia artemisiifolia L., Erigeron canadensis L., Xanthium strumarium L. and Dittrichia graveolens (L.) W. Greu…