Phytochemical investigations of the roots of Scabiosa semipapposa Salzem ex D.C. have led to the isolation of 12 undescribed triterpenoid saponins named semipapposides A-L, one undescribed saponin ...semipapposide M obtained as an inseparable mixture, together with three known oleanolic acid glycosides. Their structures were elucidated by analysis of 1D and 2D-NMR (1H–1H COSY, TOCSY, HSQC-TOCSY, HSQC, ROESY or NOESY, and HMBC) spectroscopic data and mass spectrometry (HR-ESI-MS), and by comparison with those of related metabolites. All saponins possess a partial sequence rhamnopyranosyl-(1 → 2)-xylopyranosyl or rhamnopyranosyl-(1 → 2)-arabinopyranosyl- at C-3 of the aglycon and a gentiobiose unit at C-28. These results represent a contribution to the knowledge of the saponins of Scabiosa species and their chemotaxonomy.
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•Scabiosa semipapposa Salzem ex D.C collected in Algeria was phytochemically investigated.•Thirteen previously undescribed triterpene saponins were isolated.•Their structures were elucidated by 1D, 2D-NMR and HRESIMS analyses.•This is a contribution to the chemotaxonomy of the genus Scabiosa.
•First regional flood frequency analysis in North Africa with 98 time series of river discharge.•A regional envelope curve for maximum flood in Maghreb countries is provided.•No regional trends in ...flood hazards.•Regional estimation of flood quantiles from catchment characteristics with 50% mean absolute relative errors.
The Maghreb countries located in North Africa are strongly impacted by floods, causing extended damage and numerous deaths. Until now, the lack of accessibility of river discharge data prevented regional studies on potential changes in flood hazards or the development of regional flood frequency estimation methods. A new database of daily river discharge data for 98 river basins located in Algeria, Morocco, and Tunisia, has been compiled, with an average of 36 years of complete records over the time period 1960–2018. A peaks-over-threshold sampling of flood events is considered first to detect trends in the annual frequency and the magnitude of floods. The trend analysis results revealed no significant changes in flood frequency or magnitude at the regional level, with only a few spurious trends due to isolated extreme or clustered events. An envelope curve relating maximum floods for a range of catchment areas in North Africa has been developed, for the first time in this region with such a large database. Then, regional estimation methods for flood quantiles were compared. The regional estimation from multiple catchment characteristics (including soil types, land use, elevation, and geology) was performed by comparing two multiple linear regression methods, Stepwise regression and Lasso regression, and a machine learning algorithm, Random Forests. Results indicate a better performance of the Lasso regression to estimate flood quantiles at ungauged locations, with mean absolute relative errors close to 50 % and relative bias close to 20 %. The most relevant catchment predictors identified by the regression models are the topographic wetness index, which provides better estimates than catchment area, but also altitude, mean annual rainfall, and soil bulk density. The results of this study could be useful to improve operational procedures for sizing hydraulic structures at ungauged sites.
Alzheimer’s disease is a chronic neurodegenerative disorder with no curative treatment. The commercially available drugs, which target acetylcholinesterase, are not satisfactory. The aim of this ...study was to investigate the cholinesterase inhibitory activity of Solenostemma argel aerial part. Eight compounds were isolated and identified by NMR: kaempferol-3-O-glucopyranoside (1), kaempferol (2), kaempferol-3-glu- copyranosyl(1→6)rhamnopyranose (3) p-hydroxybenzoic acid (4), dehydrovomifoliol (5), 14,15-dihydroxy-pregn-4-ene-3,20-dione (6), 14,15-dihydroxy-pregn-4-ene-3,20-dione-15β-D-glucopyranoside (7) and solargin I (8). Two of them (compounds 2 and 3) could inhibit over 50 % of butyrylcholinesterase activity at 100 µM. Compound (2) displayed the highest inhibitory effect against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with a slight selectivity towards the latter. Molecular docking studies supported the in vitro results and revealed that (2) had made several hydrogen and π-π stacking interactions which could explain the compound potency to inhibit AChE and BChE. KCI Citation Count: 0
In this paper, a novel and simplified model representing current-output phase-shift full-bridge DC-DC LCLC resonant converter in arc welding application is thoroughly presented. First, a switched ...model written in state space representation and featuring a bilinear form is proposed. The latter facilitates the derivation of both the reduced and full order averaged models in continuous conduction mode (ROAM and FOAM). Although the FOAM can be employed in linear or nonlinear control schemes and the derivation of steady state behavior, in this paper the ROAM is considered in designing both voltage mode control and current mode control by using the classical PID and the fractional order PID controllers. Simulation confirms that the switched model, ROAM and FOAM are quite accurate compared to the circuit simulation using SimPowerSystem toolbox of MATLAB/SIMULINK. Results clearly showed that depending on the switching frequency, the proposed topology can be applied either in constant voltage characteristic or dropped characteristic welding machines fulfilling either zero current Switching (ZCS) or zero voltage switching (ZVS). Besides, the fractional order PID controller seems to be more adapted for arc welding application than its traditional version.
Algeria is a country rich in natural resources; however, exports towards industrial countries required high food quality standards, which demand progresses within industry’s food control systems. ...This work was lead to evaluate the quality of 12 purchased honey samples from different origins from Algeria. Physicochemical properties, total flavonoid contents, antioxidant and antimicrobial activities by a spectrophotometric method and spectral print of honey by Raman microscopy and UV–Vis spectroscopy. The results obtained indicate a good quality level and good maturity. The discrimination between honey types was achieved by multivariate data analysis (principal component analysis and hierarchical cluster analysis). This study provides for the first time the Quantitative Spectrometric Variety-Activity Relationships (QSV-ARs) developed for predicting the antioxidant activities (DPPH and ABTS).
Six undescribed bis-iridoids named Semipapposiridoids A–F (1–6) together with seventeen known compounds were obtained from the roots and aerial parts of Scabiosa semipapposa Salzm. ex DC. Among the ...known compounds, three lignans were isolated for the first time in Scabiosa species, whereas the other known constituents including iridoids, phenol glycosides and flavonoids were previously isolated from Scabiosa sp. Their structures were assigned on the basis of extensive 1D- and 2D NMR experiments (1H, 13C, COSY, TOCSY, NOESY, HSQC, HMBC), mass spectrometry HR-ESI-MS and by comparison of their spectral data with those of literature values. To the best of our knowledge, this should be the first report on the bis-iridoids content of this plant; furthermore, the fact that the plant is rich in mono-and bis-iridoids will support chemotaxonomy of the genus. The total phenolic and flavonoid contents of the 80% MeOH extracts and fractions were evaluated, with their antioxidant activities using three different methods, namely DPPH, ABTS and CUPRAC. Most of the fractions showed a moderate to good antioxidant activity compared to the standards BHA and BHT.
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•Six undescribed bis-iridoids were isolated from aerial parts of Scabiosa semippaposa Salzm. ex DC.•Three known lignans are described for the first time in Scabiosa.•The structures of isolated compounds were elucidated by NMR and HR-ESI-MS analyses•Total phenolic contents and antioxidant activities were evaluated
Six oleanane saponins and 14 known compounds were isolated from the aerial part of Genista ulicina. The BuOH extract show no activity on human colon cancer HT-29 cells.
•Six compounds were isolated ...from aerial parts of Genista ulicina.•The structures of compounds 1–6 were determined by spectroscopic analysis.•The cytotoxicity of n-BuOH extract was evaluated on human colon cancer HT-29 cells.•This is the first report of saponins in Genista genus.
From the n-BuOH extract of the aerial parts of Genista ulicina, six triterpene saponins, 3-O-β-d-glucopyranosyl-olean-12-ene-3β,27,28,30-tetraol, 3-O-β-d-glucopyranosyl-olean-12-ene-3β,27,28,29-tetraol, 3,29-di-O-β-d-glucopyranosyl-olean-12-ene-3β,27,28,29-tetraol, 3-O-β-d-glucopyranosyl-olean-12-ene-3β,28,29-triol-27-oic acid, 3-O-β-d-glucopyranosyl-olean-12-ene-3β,27,28-triol-29-oic acid, and 3-O-β-d-glucopyranosyl-14-H-27-nor-olean-12-ene-3β,28,29-triol, were isolated together with eight known triterpene saponins and six flavonoids. Their structures were established mainly by means of spectroscopic methods (1D and 2D-NMR as well as HR-ESI-MS). The n-BuOH extract, investigated for its antitumor growth inhibition of human colon cancer HT-29 cells, presented no significant activity (IC50>100μg).
Peri-urban areas are characterized by discontinuous urbanization. The peri-urban areas are half-urban and half-rural mosaic. Now days, hydrology models are focused specifically on urban basins or ...rural basins. Almost no model is suitable for studying the transformation of rainfall-runoff peri-urban basins. In this paper we present new developments integrated in urban hydrological model “canoe”. These developments relate to the production functions of pervious area. These processes are modeled in a continuous time.
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