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Advances in Biological Chemistry 2024年第1期14卷 27-39页

作者： donald léonel feugap tsamo Cyrille Ngoufack Tagousop Arnaud Joseph Nguetse Dongmo laurence Voutquenne-Nazabadioko David Ngnokam Research Unit of Applied and Environmental Chemistry Department of Chemistry Faculty of Science University of Dschang Dschang Cameroon Department of Organic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Department of Basic Scientific Studies University Institute of Technology University of Ngaoundéré Ngaoundéré Cameroon Groupe Isolement et Structure Institut de Chimie Moléculaire de Reims (ICMR) Reims France

Starting from sissotrin (1), a natural isoflavonoid isolated from Trifolium baccarinii (Fabaceae), one new semisynthetic derivative, 6-nitrobiochanin A (1b) and two known derivatives, 8-nitrobiochanin A (1a) and 2",3",4",6"-tetraacetylsissotrin (1c) have been obtained after performing nitration and acetylation reactions. Their structures were assigned after interpretation of their spectrometric (HR-ESI-MS) and spectroscopic (NMR 1D and 2D) data and by comparison with those reported in the literature. The substrate as well as the semisynthetic derivatives were evaluated for their antibacterial activities against six strains. The results reveal that they are inactive or weakly active on the strains tested with the exception of 8-nitrobiochanin A (1a) which showed moderate activity (MIC = 62.5 μg∙ml−1) on Staphylococcus aureus ATCC 43300.

关键词： Trifolium baccarinii Isoflavonoid Nitration Acetylation Antibacterial Activity

Physico-Chemical Properties of Soils from Diguel and Koudalwa Tchad,and Phytoremediation Potentials of Acasia and Kinkeliba Plants in Removing Cr and Cu from These Soils

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Journal of Environmental Science and Engineering(A) 2024年第5期13卷 165-177页

作者： Dieudonne Caleb Dahaina Jean Claude Doumnang Mbaigane Bobet Ouanmini Cornelius tsamo Department of Chemistry Faculty of Exact and Applied SciencesUniversity of N’DjamenaBP 1027N’DjamenaChad laboratoire de Géologie Géomorphologie et TélédétectionFacultédes Sciences Exactes et AppliquéesUniversitéde N’DjaménaBP 1027N’DjamenaChad laboratoire de Chimie Ecole Normale Supérieure de BongorBP 13BongorTchad Department of Chemistry Higher Teachers’Training CollegeUniversity of MarouaP.O.Box 55 MarouaCameroon Department of Agricultural and Environmental Engineering College of TechnologyUniversity of BamendaP.O.BOX 39BambiliCameroon

The aim of this study to investigate the physico-chemical properties of soils from Diguel and Koudalwa Tchad,and phytoremediation potentials of acasia and kinkeliba plants in removing Cr and Cu from these *** was sampled from the tannery plant in Diguel and agricultural land around crude oil activities in *** were characterized by the following properties:pH,(Electrical Conductivity),TDS(Total Dissolved Solids),salinity,bulk density,OM(Organic Matter),nitrate,phosphate,clay,silt,sand,and textural *** acasia and kinkeliba plants were used to decontaminate Cu and Cr from sample soils for 30 days *** bulk density of all the soil samples from Kouldawa was higher compared to Diguil,ranging from 1.421 to 1.64 g/cm^(3)compared to 1.21 to 1.51 g/cm^(3)for *** of the soils in Kouldawa are mineral soils,while those of Diguel are mostly mineral soil with some *** soils are richer in nitrate(577.9 to 2,687.32 mg/kg in Diguel and 33.64 to 197.64 mg/kg in Kouldawa)and phosphate than soils from *** from the studied areas are not saline except for a subsurface soil in Diguel(salinity,4.21;EC,4.280 dS/m;TDS,3,040 mg/l).The highest amount of Cr and Cu removed by acasia is 78%and 53.12%compared to 73.8%and 52.21%by *** soil can be very suitable for agriculture and Kouldawa soils for *** and kinkeliba can be effectively used to decontaminate the studied soils from heavy metal pollution.

关键词： Soil physico-chemical properties phytoremediation heavy metals Tchad.

A New Ceramide (Rumexamide) and Other Chemical Constituents from <i>Rumex abyssinicus</i>Jacq (Polygonaceae): Isolation, Characterization, Antibacterial Activities and Chemophenetic Significance

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Advances in Biological Chemistry 2021年第5期11卷 266-282页

作者： léonel donald feugap tsamo lorette Victorine Yimgang Steven Collins N. Wouamba Pierre Mkounga Augustin Ephrem Nkengfack laurence Voutquenne-Nazabadioko David Ngnokam Bruno Ndjakou lenta Norbert Sewald Research Unit of Applied and Environmental Chemistry Department of Chemistry Faculty of Science University of Dschang Dschang Cameroon Department of Organic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Antimicrobial Agents Unit Laboratory for Phytobiochemistry and Medicinal Plants Studies University of Yaoundé I Yaoundé Cameroon Department of Chemistry Higher Teacher Training College University of Yaounde I Yaoundé Cameroon Groupe Isolement et Structure Institut de Chimie Moléculaire de Reims (ICMR) Reims France Organic and Bioorganic Chemistry Faculty of Chemistry Bielefeld University Bielefeld Germany

The chemical study of Rumex abyssinicus Jacp (Polygonaceae) led to the isolation of a new ceramide named (R)-2'-hydroxy-N-[(2S,3S,4R,16E)-1,3,4-trihydroxyhexacos-16-en-2-yl]hexadecanamide (rumexamide) (1) together with sixteen known compounds: bis-(2-ethylhexyl) phthalate (2), chrysophanol (3), physcion (4), citreorosein (5), emodin (6), chrysophanein (7), physcionin (8), lupeol (9), 3β,28-dihydroxylup-20(29)-ene (10), 3β-dihydroxylup-20(29)-en-28-oic acid (11), oleanolic acid (12), ergosta-6,22-diene-3,5,8-triol (13), stigmastane-3,6-dione (14), a mixture of β-sitosterol (15) and stigmasterol (16), and stigmasterol 3-O-β-D-glucoside (17). Their structures were determined by interpretation of their spectroscopic 1D NMR (1H and 13C NMR), 2D NMR (COSY 1H-1H, HSQC and HMBC) data in conjunction with mass spectrometry (TOFESIMS and HR-TOFESIMS) and by comparison with those reported in the literature. Among all the known compounds, twelve (2, 5, 8-17) were firstly isolated from Rumex abyssinicus, seven (2, 10-14 and 17) from the genus Rumex and three (13, 14, 17) from family Polygonaceae. The in vitro antibacterial activities of extracts (MeOH, n-BuOH and EtOAc),le="font-family:""> as well as compounds 9,

关键词： Polygonaceae Rumex abyssinicus Rumexamide Antibacterial Activities Chemophenetic Significance

New Hemisynthetic Oleanane Saponin with Antimicrobial Activities

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Advances in Biological Chemistry 2021年第1期11卷 1-11页

作者： Cyrille Ngoufack Tagousop Jean-De-Dieu Tamokou leonel donald tsamo feugap Dominique Harakat laurence Voutquenne-Nazabadioko David Ngnokam Department of Basic Scientific Studies University Institute of Technology University of Ngaoundere Ngaoundere Cameroon Research Unit of Environmental and Applied Chemistry Department of Chemistry Faculty of Science University of Dschang Dschang Cameroon Research Unit of Microbiology and Antimicrobial Substances Department of Biochemistry Faculty of Science University of Dschang Dschang Cameroon Service Commun d’Analyses Institut de Chimie Moléculaire de Reims (ICMR) CNRS UMR 7312 Reims France Groupe Isolement et Structure Institut de Chimie Moléculaire de Reims (ICMR) CNRS UMR 7312 Reims France

A new hemisynthetic oleanane saponin: 4',2",3",4",6"-penta-O-acetyl-6'-O- methyl-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyranosyl oleanolic acid (2) was obtained after acetylation and methylation reaction on 3-O... 详细信息

关键词： Saponin Acetylation Methylation Antimicrobial Activities

Effects of extracts from Hibiscus macranthus and Basella alba mixture on testosterone production in vitro in adult rat testes slices

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Asian Journal of Andrology 2006年第1期8卷 111-114页

作者： Paul E Moundipa Silvère Ngouela Pierre Kamtchouing Etienne tsamo Félicité M.Tchouanguep Serge Carreau laboratory of Nutrition and Biochemical Toxicology laboratory of Organic Chemistry Department of Animal Biology and Physiology University of Yaoundé IP.O.Box 812YaoundéCameroon Faculty of Science University of DschangP.O.Box 67DschangCameroon USC INRA-EA 2608.laboratoire de Biochimie Esplanade de la paixUniversité de Caen14032 Caen-cedexFrance

Aim： To find an in vitro system for the measurement of the androgenic effects of different extracts of Hibiscus macranthus （Malvaceae） and Basella alba （Basellaceae）. Methods： The production of testosterone from testes slices incubated in two media, either Krebs-Henseleit buffer containing 0.5% Bovine serum albumin （BSA） or Dubecco＇s Modified Eagle＇s medium-F12 Ham nutrient mixture （DME/Ham F12）, under a mixture of 5% CO2 in 95% air was determined either in the presence or absence of cofactors and Hibiscus macranthus plus Basella alba （HMBA） extracts. Results： The testosterone production was increased in testes slices incubated in DME/Ham F12 medium in response to the cofactors （49%） and aqueous extracts （34%-60% according to dilutions）. Under the same atmospheric conditions, there was no positive response of the testes slices to either cofactor or HMBA extract stimulation in Krebs-Henseleit buffer containing 0.5% BSA, In further investigations related to the effect of HMBA, the DME/ Ham F12 medium was used. The results obtained from the in vitro test showed that the activity was present mainly in methylene chloride and methanol, since these extracts induced an increase in testosterone production by testes slices. Conclusion： The testes slice system is suitable to be used for further in vitro investigations of the isolation of androgenic bioactive components of plants. （Asian J Androl 2006 Jan; 8： 111-114）

关键词： testis testosterone plant extracts Hibiscus macranthus Basella alba

Effects of Basella alba and Hibiscus macranthus extracts on testosterone production of adult rat and bull leydig cells

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Asian Journal of Andrology 2005年第4期7卷 411-417,页

作者： Paul F.Moundipa Nathalie Sara E.Beboy Fabien Zelefack Silvère Ngouela Etienne tsamo Wolf-Bernhard Schill Thomas K.Monsees Departments of Biochemistry Organic Chemistry University of Yaounde IP.O.Box 812 YaoundeCameroon Centre for Dermatology and Andrology Justus Liebig UniversityGaffkystr.1435385 GiessenGermany Centre for Dermatology and Andrology Justus Liebig UniversityGaffkystr.1435385 GiessenGermany Department of AnatomyUniversity of TechnologyFetscherstr.7401307 DresdenGermany

Aim： To determine the androgenic effects of Basella alba and Hibiscus macranthus extracts in the rat and the bull, and to develop a novel in vitro test system using leydig cells from bull testes. Methods： The effect of methanol extracts from both plants on testosterone production in isolated leydig cells from the rat and the bull was analyzed using ^125I-radioimmunoassay （^125I-RIA）. Rat leydig cells were obtained by common methods, whereas a novel technique was used to purify leydig cells from bull testes. Results： Bull testes from the slaughter house were a cheap source of pure leydig cells. In culture, these cells produced testosterone for 5-6 days, which can be stimulated by human chorionic gonadotrophin （hCG）. Basella alba extracts significantly enhanced testosterone production in bull and rat leydig cells in a concentration-dependent manner. Hibiscus macranthus showed no androgenic effect but was shown to inhibit testosterone production at higher concentrations. Conclusion： leydig cells purified from bull testes can be used as an alternative tool in experimental animal research. Certain fractions of Basella alba extract demonstrated androgenic potential whereas Hibiscus macranthus extracts did not.

关键词： bull rats leydig cells testosterone Basella alba Hibiscus macranthus plant extract

Influence of CRT Glass Quantity on the Properties of Red Mud-CRT Glass Ceramics Fired at Different Temperatures

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材料科学与工程（中英文B版） 2019年第4期9卷 133-143页

作者： Paul Nestor Djomou Djonga Cornelius tsamo Harouna Massai Department of Chemistry Faculty of ScienceUniversity of MarouaMarouaP.O.Box 46Cameroon Department of Chemistry Higher Teachers’Training CollegeUniversity of MarouaMarouaP.O.Box 55Cameroon

This paper reports the production of ceramics using CRT(cathode ray tube)glass and red mud by varying the amount of waste glass and firing from 700-950℃.The raw materials were characterized using chemical composition,IR(infra-red spectroscopy),XRD(X-ray diffraction),DSC-TGA(differential scanning calorimetry-thermo gravimetric analyses)and SEM(scanning electron microscopy)*** ceramic specimen was produced by mixing a constant quantity of red mud and 0%-40%of waste glass,then firing from 700-950℃.The linear shrinkage,water absorption,apparent porosity,bulk density,weight loss on ignition,flexural strength and chemical resistance test were used to evaluate the produced *** materials had good fluxing properties which were improved with *** the specimens produced had water absorption values below the maximum value of 20% specified by the norm for roofing tiles while specimens with 30%-40% CRT glass and fired at 850°C,and specimens with 20%-40% CRT glass and fired at 950℃ had water absorption values below 10%,which is the norm for ceramic *** specimens 0%-40% CRT glass fired at 950℃,specimens 5%-40% CRT glass fired at 850℃,specimens 10%-40% CRT glass fired at 750℃ and specimen with 20%CRT glass fired at 700℃,water absorption values were all lower than 17% which is ASTM C62 specifications for *** norm of flexural strength for floor tiles>25 MPa but all values were less than 25 *** ceramic shows a maximum loss of 0.10%in HNO3 against 0.06%for *** two waste materials can effectively be used to produce ceramic materials with good properties.

关键词： CRT glass red mud ceramics firing roofing tiles floor tiles

Variation in Total Soil Organic Carbon Stocks in Relation to Some land Use Systems in the Bamenda Highlands, Cameroon

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Journal of Geoscience and Environment Protection 2021年第9期9卷 150-165页

作者： Christian Tegha Kum Aaron Suh Tening Martin Ngwabie Cornelius tsamo Department of Agricultural and Environmental Engineering College of Technology The University of Bamenda Bamenda Cameroon Department of Agronomic and Applied Molecular Sciences Faculty of Agriculture and Veterinary Medicine University of Buea Buea Cameroon

Climate change and food security are among the pressing challenges facing humanity in the 21st century. Soil organic carbon (SOC) stocks, total nitrogen (TN), texture, and bulk density (BD) are important soil properties, which control climate change. Three land use systems (smallholder farmlands, grazing lands, and forest lands) that coexist in the Bamenda Highlands (BH) influence ecosystem services and induce soil degradation with the loss of SOC. The objective of this study was to evaluate the variation of SOC and some soil physicochemical properties as affected by the three land use systems (LUS). A total of 21 composite soil samples collected from 7 microclimatic zones of BH following “S” shape plots to the depth of 0 - 30 cm, were analysed for moisture content (MC), SOC, TN, BD, available phosphorus (Av.P), pH and texture. The results revealed that grazing land had the lowest mean sand content (40.79 ± 4.07). Mean MC, TN and SOC (%) content were significantly higher (p in forest land than those in the grazing land and smallholder farmlands. Conversely, BD and Av.P were significantly higher le="font-fami

关键词： Soil Soil Organic Carbon land Use Systems Bamenda Highlands Soil CO2 Emissions

Germination and Survival of Maize and Beans Seeds: Effects of Irrigation with NaCl and Heavy Metals Contaminated Water

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Open Journal of Applied Sciences 2022年第5期12卷 769-792页

作者： Cornelius tsamo Sendze Martinien Alanyuy Eric Fru Zama Chi Christopher Tamu Department of Agricultural and Environmental Engineering College of Technology University of Bamenda Bambili Cameroon Department of Chemistry Higher Teachers’ Training College University of Maroua Maroua Cameroon

Metal toxicity and soil salinity at excessive levels in soils are toxic to plants. The main objective of this study was to demonstrate the effects of water salinity (NaCl) and heavy metal concentration on germination and seedling characteristics of maize and beans seeds. Different concentrations of NaCl (0 to 35000 mg/l) and Zn2+, Cu2+ and Pb2+ with concentrations 0 to 600 μmol/l each were used separately. These solutions were used to irrigate maize and bean seeds for 30 days. Data was taken daily for the following parameters;“the number of germinated seeds, shoot length, shoot circumference, leaf area index, leaf colors, senescence, and disease occurrences.” The crops were uprooted at the end of the 30 days and their wet masses were measured and recorded. Results indicated that seed germination reduced with an increase in the concentration of NaCl for both maize and beans with 0% germination recorded in concentrations > 5000 mg/l. The same trends were observed for other parameters, the shoot length, the leaf area index, and the shoot circumference. “For heavy metals, the trends were similar. Beans growth was more affected by Zn and Cu but maize growth was more affected by Pb.” The dry masses and wet masses of the crops with higher concentrations of metals and salts were very low compared to the control experiments. For the effects of salinity and heavy metals on beans and maize seeds, there was a significant difference (P ≤ 0.001) between all tested concentrations and the control for all growth parameters monitored. It was concluded from the results that salinity and heavy metals affect the germination and seedling characteristics of maize and beans;though some metals are essential, their presence in higher concentrations instead cause harm.

关键词： Salinity Heavy Metals Pollution Seedling Characteristics Irrigation

Techniques and Technological Aspects of Palm Oil (Elaeis guineensis) Processing in Cameroon

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World Journal of Engineering and Technology 2023年第4期11卷 756-769页

作者： Godlove Nfor Njeshu Ngwa Martin Ngwabie Divine Nde Bup Cornelius tsamo Department of Agricultural and Environmental Engineering College of Technology The University of Bamenda Bamenda Cameroon Department of Food and Bio-Resource Technology College of Technology The University of Bamenda Bamenda Cameroon

Crude palm Oil (CPO) processing is very popular in African Countries. In Cameroon, various actors are involved ranging from agro-industrial complexes to traditional processing by smallholders who use very inefficient equipment and thus have low oil extraction rates. Small-scale processing by smallholders dates back to the early 1980s and has witnessed a lot of changes as a result of new actors in the sector, changing technologies and to an extent, government policies. This paper attempts a review of the origins and evolution of small-scale palm oil processing using intermediate technology, highlighting its importance to both the farmer and the national economy. An attempt is made to look into the future of this activity, with proposals for its consolidation.

关键词： CPO Small-Scale Processing Oil Extraction Rates Intermediate Technologies