Synthèse et réactivité des dérivés de la quinoléine : préparation des isoxazoles et isoxazolines quinoléiques par des réactions de cycloaddition 1,3-dipolaires

The main objectif of this work is the synthesis of new five-membred heterocycles containing the quinoline moeity via a 1,3-dipolar cycloadition reaction of nitrile oxide with dipolariphiles in goal of discover a new compounds potentially actives in different domains notably in pharmacy and biology

Comparative study of antibiofilm, cytotoxic activity and chemical composition of Algerian propolis

Antimicrobial agents are one of the strategies for inhibition of biofilm formation. But, most antimicrobials are not often effective in controlling of biofilm formation. Therefore, finding of new materials that have biofilm inhibitory effects is so important. In this regard, we aimed to determine the antibiofilm and cytotoxic effect of five Algerian propolis extracts obtained by extraction in solvents of varying polarity. Propolis extracts were tested for their ability to inhibit biofilm formation and to reduce preformed biofilm of eight bacterial strains including reference strains of Staphylococcus aureus (S. aureus ATCC29213 and S. aureus ATCC33862), three methicillin-resistant S. aureus (M10-1, M18-3, and M20-1), Enterococcus faecalis ATCC19433, Micrococcus luteus NRRL-B1013, and Yersinia enterocolitica RSKK1501. Cytotoxic activities of propolis extracts were determined using MTT test. Chemical investigation was performed using ultra-performance liquid chromatography with electrospray ionization coupled to tandem mass spectrometry (UPLC-ESI-MS/MS). All tested extracts exhibited the highest eradicating capability for S. aureus reference strains and methicillin-resistant strains, especially MRSA18-3 and MRSA20-1.The reduction of biofilm formation was found to be significantly affected by the used solvent for maceration, the tested bacterial strains, and the origin of tested propolis. In addition, biofilm reduction of Algerian propolis seemed to be dose-dependent. Moreover, all extracts showed high cytotoxic activity in colon adenocarcinoma cells. In addition, twenty-six phenolic compounds were detected. Difference between the amounts of detected compounds was found to be significant. Caffeic and ferulic acids were the main compounds in the tested extracts. These results suggest that those compounds might be responsible for the observed antibiofilm and cytotoxic activities of propolis extracts. © 2019, © 2019 International Bee Research Association

Ferulenol specifically inhibits succinate ubiquinone reductase at the level of the ubiquinone cycle

The natural compound ferulenol, a sesquiterpene prenylated coumarin derivative, was purified from Ferula vesceritensis and its mitochondrial effects were studied. Ferulenol caused inhibition of oxidative phoshorylation. At low concentrations, ferulenol inhibited ATP synthesis by inhibition of the adenine nucleotide translocase without limitation of mitochondrial respiration. At higher concentrations, ferulenol inhibited oxygen consumption. Ferulenol caused specific inhibition of succinate ubiquinone reductase without altering succinate dehydrogenase activity of the complex II. This inhibition results from a limitation of electron transfers initiated by the reduction of ubiquinone to ubiquinol in the ubiquinone cycle. This original mechanism of action makes ferulenol a useful tool to study the physiological role and the mechanism of electron transfer in the complex II. In addition, these data provide an additional mechanism by which ferulenol may alter cell function and demonstrate that mitochondrial dysfunction is an important determinant in Ferula plant toxicity

Isolation and identification of five free flavonoid aglycones from Thymus numidicus

International audienceFrom the aerial parts of the endemic species Thymus numidicus Poiret locally which is known as "zaatar", belongs to the Lamiaceae family five flavonoids were isolated using chromatographic techniques and identified by spectral analysis (UV-Visible, MS, 1H and 13CNMR) and chromatographic behaviours

Chemical composition of the essential oil from algerian genista quadriflora munby and determination of its antibacterial and antifungal activities

International audienceThe hydrodistilled oil of the aerial parts from Genista quadriflora growing in Algeria was analyzed by gas chromatography-flame ionization detection (GC/FID) and gas chromatography-mass spectrometry (GC/MS). Altogether 222 volatile substances, representing around 77% of the essential oil was identified. The major constituents were the sesquiterpenes muurolan-4,7-peroxide (19.42%), amorpha-4,9-dien-2-ol (10.40%), alpha-cadinol (2.29%), caryophyllene oxide (1.47%) and germacra-4(15),5,10(14)-trien-1-alpha-ol (1.39%). Fatty acids were the second most abundant compounds of the essential oil detected with dodecanoic acid (lauric) (3.14%), hexadecanoic acid (palmitic) (2.49%) and tetradecanoic acid (myristic) (1.12%) as main components. The volatile oil was screened in vitro for antibacterial and antifungal activities using dilution and disc diffusion methods. Thus, the crude essential oil exhibited a marked antifungal activity against Fusarium oxysporun and a significant inhibition activity was registered towards a Gram-negative bacterium Proteus mirabilis. Substantial antibacterial activity was also recorded against Gram-positive bacteria with MIC: 0.9 +/- 0.1 and 1.7 +/- 0.3 mg/ml for Staphylococcus aureus suggesting the possibility to use of G. quadriflora essential oil in the development of new drugs for treatment of infectious diseases

Volatiles of Algerian Daucus rebaudii Coss. rich in (E)-anethole and their antioxidant activity

The essential oils obtained from the aerial parts of Daucus reboudii Coss. (Apiaceae) which is endemic to north Africa collected from Algeria were analyzed by GC/MS. 28 compounds were identified accounting for 97.8% of the total oil, the result shows the dominance of the phenylpropanoids derivatives. (E)-anethol (59.4%) was the main constituents identified in the essential oil, followed by estragol (21.2%) and dodecanal (4.4%). In vitro antioxidant antioxidant activity of the Essential oils were assayed using DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging, ß- carotene and ABTS+ assay, the results indicated that D.reboudii oil recorded a moderate capacit

Analysis of pyrrolizidine alkaloids and evaluation of some biological activities of Algerian Senecio delphinifolius Vahl (Asteraceae)

Although Senecio species are known as sources of potentially toxic pyrrolizidine alkaloids (PAs), some species of this genus are traditionally used as remedies, notably in Algeria. In this paper, the evaluation of biological activities and the analysis of PAs of Algerian specimens of Senecio delphinifolius Vahl are reported. The n-butanolic extract of the herb showed a weak antibacterial effect against Escherichia coli with a MIC of 1 mg/mL, but was inactive against Staphylococcus aureus and Pseudomonas aeruginosa. The n-butanolic extracts of the roots, stems and herb showed a modest antioxidant activity, scavenging the free radical DPPH with respective IC50 values of 55.3, 50.2 and 13.3 μg/mL. A cytotoxic effect against a series of human tumor cell lines was observed with the n-butanolic extract from stems (IC50 ranging between 34 and 88 μg/mL). The herb of the evaluated sample contains 140 ppm of PAs (senecionine, seneciphylline, integerrimine, senkirkine) and PA-related alkaloids (dehydrosenkirkine and neosenkirkine). As the major PAs belong to the toxic series (1,2-unsaturation in the pyrrolizidine cycle and macrocyclic diester), the use of S. delphinifolius should be discouraged in traditional medicine.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Disruption of mitochondrial membrane potential by ferulenol and restoration by propolis extract: Antiapoptotic role of propolis

This paper reports an investigation of the ability of propolis extract (a resinous substance collected by honeybees from various plant sources) to restore the collapse of mitochondrial membrane potential induced by ferulenol, a sesquiterpene prenylated coumarin derivative isolated from the plant Ferula vesceritensis . We show that ferulenol was able to induce the permeability transition pore (PTP) opening. This effect is caused by the interaction of the compound with the mitochondrial respiratory chain, more particularly by the fall of membrane potential and the inhibition of complex II. We have previously demonstrated that this inhibition results from a limitation of electron transfers involved in the respiratory chain and initiated by the reduction of ubiquinone. We hypothesized that the protective effect of propolis could be due to a direct action on mitochondrial functions. So we have investigated in vitro the mitochondrial effects of Algerian propolis using rat liver mitochondria, by analysing their effects on membrane potential, mitochondrial respiration and mitochondrial swelling. We show that propolis extract was able to restore the fall of mitochondrial membrane potential. Taken together these data reveal that propolis extract may be an interesting inhibitor of PTP and provide an additional mechanism by which the natural product propolis extract may restore the mitochondrial membrane potential and to prevent apoptotic process