Publications by authors named "Dongo E"

The development of agricultural waste-doped fired bricks is an important step toward achieving lightweight eco-efficient bricks with improved thermal insulation property. Recent research in masonry has been tailored towards the production of energy-efficient building by incorporating waste materials as additives. This effectuates a safe waste disposal, cost effectiveness, and also serve as a giant stride towards environmental sustainability.

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Background And Aims: Endogenous gaseous substances, such as NO and CO have been found to be effective vasodilators earlier. H2S has been identified as an additional one, however, for that substance both vasodilatory and vasoconstrictor responses have been described in different vascular territories. Our aim was to examine the effect of hydrogen sulfide on the tone of cerebral arterioles and some aspects of its mechanism.

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A better understanding of the regulation of cerebrovascular circulation is of great importance because stroke and other cerebrovascular diseases represent a major concern in healthcare leading to millions of deaths yearly. The circulation of the central nervous system is regulated in a highly complex manner involving many local factors and hydrogen sulfide (HS) is emerging as one such possible factor. Several lines of evidence support that HS takes part in the regulation of vascular tone.

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The roots of Schweinf are used in traditional medicine to treat intestinal helminthiasis. The aim of this study was to assess the effect of roots methanolic extract (OPME) on liver injury induced by in mice. A preliminary phytochemical study of OPME was conducted.

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Background: Hydroquinone-containing creams cause false increases in capillary glycemia. However, the magnitude of this false increase, and the means to reverse it have not been investigated.

Objective: To evaluate the technical and clinical impact of hydroquinone-containing creams on capillary glycemia and investigate the efficacy of hand washing and other common practices, in reversing cream effects.

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Our knowledge about hydrogen sulfide (HS) significantly changed over the last two decades. Today it is considered as not only a toxic gas but also as a gasotransmitter with diverse roles in different physiological and pathophysiological processes. HS has pleiotropic effects and its possible mechanisms of action involve (1) a reversible protein sulfhydration which can alter the function of the modified proteins similar to nitrosylation or phosphorylation; (2) direct antioxidant effects and (3) interaction with metalloproteins.

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Thromboangiits obliterans (Buerger's disease) is a non-atherosclerotic, segmental inflammatory and obliterative disease affecting small and medium sized arteries and veins. The etiology is still unknown, but it is in close relationship with tobacco use. Symptoms begin under the age of 45 years and the undulating course is typical.

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Background: The intensive use of Praziquantel for the treatment of schistosomiasis has raised concerns about the possible emergence of drug-resistant schistosomes. As drug treatment is an important feature of schistosome control programs, the search for alternative drugs is therefore a priority. The aim of this study was to assess the schistosomicidal, hepatoprotective and antioxidant activities of the methanolic fraction from Clerodendrum umbellatum Poir leaves aqueous extract.

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Aims: A major limitation of cell-based therapies for ischemia-reperfusion injury is the excessive loss of administered cells. We investigated whether H2S can improve the survival and efficacy of therapeutic cells in an in vitro model of cell-based therapy for simulated ischemia.

Main Methods: H9c2 rat cardiomyoblasts were exposed to oxygen-glucose deprivation and NaHS (3-30 μM) pretreated human adipose tissue derived stem cells (hASCs) were added after reoxygenization.

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Phytochemical investigations on the stem bark and roots of the tropical shrub Clausena anisata led to the isolation and characterization three carbazole alkaloids: girinimbine, murrayamine-A and ekeberginine; two peptide derivatives: aurantiamide acetate and N-benzoyl-L-phenylalaninyl-N-benzoyl-L-phenylalaninate; and a mixture of two phytosterols: sitosterol and stigmasterol. The structures of these compounds were established by nuclear magnetic resonance (1H-NMR, 13C-NMR, COSY, HSQC, HMQC, HMBC and NOESY) spectroscopy and electrospray ionization mass spectrometry (MS).

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This article deals with a phytochemical investigation of Melicia excelsa from which melicilamide A (1), a new ceramide has been isolated. Its structure was determined by comprehensive analyses of its (1)H- and (13)C-NMR, COSY, HMQC and HMBC spectroscopic, EI-MS and ESI-MS data. The remaining one known compound was identified as β-sitosterol glucopyranoside.

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Myocardial infarction is responsible for the majority of cardiovascular mortality and the pathogenesis of myocardial damage during and after the infarction involves reactive oxygen species. Serious efforts are under way to modulate the developing ischemia/reperfusion injury and recently the use of hydrogen sulfide (H2S) emerged as a new possibility. H2S has been best known for decades as a pungent toxic gas in contaminated environmental atmosphere, but it has now been recognized as a novel gasotransmitter in the central nervous and cardiovascular systems, similarly to nitric oxide (NO) and carbon monoxide (CO).

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Cordia platythyrsa Baker is known for its medicinal value. This paper deals with a phytochemical investigation of this species, from which cordioxime (1), a new dioxime y-lactam has been isolated. Its structure was determined by comprehensive analyses of its 1H and 13C NMR, COSY, HMQC, and HMBC spectroscopic, and HREIMS data.

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Two new alkylanacardic acids, ozorcardic A (1) and B (2), along with the known and related metabolite anacardic acid (3), were isolated from Ozoroa pulcherrima. The structures of the new compounds were elucidated by detailed spectroscopic and spectrometric analysis.

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One new bicyclic polyprenylated compound, dorstenpictanone (1), was isolated from Dorstenia picta. The structure of the new compound was elucidated by detailed spectroscopic analysis such as (1)H NMR, (13)C NMR, COSY, HMQC, HMBC, and HREIMS. The relative configuration of dorstenpictanone (1) was distinguished by comparative analysis of the NMR spectral data with known analogues together with the ROESY experiment.

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Phytochemical investigation of Hylodendron gabunensis resulted in the isolation of two new glyceride derivatives, hyloglyceride (1) and hylodiglyceride (2). The structures of the two new compounds were determined by comprehensive analysis of their 1D and 2D NMR spectroscopic, and HREIMS data. One known compound was also isolated and identified as beta-sitosterol.

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One new alkylanacardic acid, ozocardic A (1), along with the known and related metabolites 6-tridecyl anacardic acid (2) and β-sitosterol (3) was isolated from Ozoroa pulcherrima. The structure of the new compound was elucidated by detailed spectroscopic analysis such as (1)H, (13)C NMR, COSY, HMQC, HMBC, and HREIMS. The structures of known compounds (6-tridecyl anacardic acid (2) and β-sitosterol (3)) were identified by the comparison of their spectral data with those published in the literature.

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Pycnanthus anglonensis is known for its medicinal value. This paper deals with a phytochemical investigation of this species, from which pycnangloside (1), a new cerebroside has been isolated. Its structure was determined by comprehensive analyses of its 1D and 2D NMR spectroscopic, and ESI mass spectrometric data.

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We present a new and advanced methodology, developed for surface functionalisation of gold and to study immobilisation of an immuno-specific system of proteins. A combination of electrochemical quartz crystal microbalance and Raman spectroscopy techniques allowed a complete understanding of the system starting from surface functionalisation and progressing to the functional structure analysis of immobilised proteins. A simple electrochemical procedure was formulated to prepare sulphonyl chloride terminated gold surfaces that form a strong sulphonamide bond with the receptor protein staphylococcal protein A (SpA).

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From the extracts of all parts of the plant Helichrysum cameroonense, five compounds were isolated and identified. One of them, a ceramide, named cameroonemide A (1), is reported for the first time as a new natural product. Its structure was determined by comprehensive analyses of their 1D and 2D NMR and HR-EI-MS spectral data.

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From the methanol extract of the stem bark of the African tree Antiaris africana Engler, two new bioactive metabolites were isolated, namely, the α-amyrin derivative 1β,11α-dihydroxy-3β-cinnamoyl-α-amyrin (antiarol cinnamate, 1) and a cardiac glycoside, 3β-O-(α-L-rhamnopyranosyl)-14β-hydroperoxy-5β-hydroxy-19-oxo-17β-card-20(22)-enolide (africanoside, 2a), together with the known compounds β-amyrin and its acetate, β-sitosterol and its 3-O-β-D-glucopyranoside, friedelin, ursolic and oleanolic acid, 19-norperiplogenin, strophanthidol, strophanthidinic acid, periplogenin (3a), 3-epiperiplogenin, strophanthidin (3b) and 3,3'-dimethoxy-4'-O-β-D-xylopyronosyl-ellagic acid. Their structures were established on the basis of their spectroscopic data and by chemical methods, while 3a was additionally confirmed by X-ray crystal structure analysis. The aglycone moiety possessing a hydroperoxy group was found for the first time in cardenolides.

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Eight compounds were isolated from the stem bark of the plant Afraegle paniculata. One of them, a dimethyl ether of S-trans-marmin (1), is reported as a new natural product. The structures were determined by comprehensive analyses of their 1D and 2D NMR spectroscopic and HREIMS data.

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Sclerocarya birrea is a medicinal plant used for the treatment of inflammatory- and bacterial-related diseases. The present study investigated in vitro and in vivo the effects of the stem bark methanol extract of S. birrea.

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Sclerocarya birrea is a plant widely used as traditional medication for the treatment of diabetes in sub-Saharan regions. However, the mechanism of action is unknown and only hypoglycaemic effects of S. birrea extract (SBE) in diabetic rats have been reported to date.

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