Alfred Ngenge Tamfu

University of Ngaoundere · School of Chemical Engineering and Mineral Industries

This study explores Daucus crinitus extracts (DCE) and zinc oxide nanoparticles (ZnO-NPs) synthesized using the extracts as corrosion inhibitors for carbon steel (CS) in HCl medium. The synthesized ZnO-NPs were characterized via UV-vis spectroscopy, exhibiting a peak at approximately 375 nm. The study employed weight loss (WL) and electrochemical m...

Alzheimer’s disease (AD) and diabetes are non-communicable diseases with global impacts. Inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are suitable therapies for AD, while α-amylase and α-glucosidase inhibitors are employed as antidiabetic agents. Compounds were isolated from the medicinal plant Terminalia macroptera an...

Background: Pseudomonas aeruginosa is an opportunistic, resistant and highly pathogenic bacteria, responsible for severe nosocomial infections in humans. There is need to search new antimicrobials to target P. aeruginosa strains. Cistus munbyi is used in traditional medicine to manage infections. Objectives: This work aims to investigate the antimi...

The ability of Centaurea napifolia extracts, hydro-methanolic (HME), methylene dichloride (MDE), ethyl acetate (EAE), and n-butanol (BE), to inhibit carbon steel (CS) corrosion in acidic environments and to function as additives in mild steel (MS) electroplating baths with pure zinc is assessed in this study. Potentiodynamic polarization, gravimetr...

In recent years, there have been an attempt to develop safe and environmental friendly solvents to replace conventional solvents, and use for extraction bioactive compounds from natural sources. A current investigation involved the preparation of green, methanolic, and ultrasonic extracts of S. sclarea, and compared their phenolic profiling using H...

Sanguisorba minor is a medicinal vegetable used in seasoning desserts, juices, and beverages. An evaluation of the total flavonoid, phenolic, tannin and anthocyanin contents indicated that these classes of compounds are distributed variably in the different fractions. In summary, the HPLC-DAD analyses enabled the identification and quantification o...

Resistance to antibiotics by pathogenic bacteria constitutes a health burden and nanoparticles (NPs) are being developed as alternative and multipurpose antimicrobial substances. Magnetite (Fe 3 O 4 np), manganese ferrite (MnFe 2 O 4 np) and nickel ferrite (NiFe 3 O 4 np) NPs were synthesized and characterized using thermogravimetric analysis, tran...

Water is essential to life, but access to uncontaminated water remains a global challenge. Metal oxides possess particular characteristics required for removing heavy metals, inorganic and organic pollutants from wastewater as well as inhibiting microorganisms. Zirconium oxide and alginate which are nontoxic materials were used to synthesize hydrat...

Background Microbial infections cause serious health problems especially with the rising antibiotic resistance which accounts for about 700,000 human deaths annually. Antibiotics which target bacterial death encounter microbial resistance with time, hence, there is an urgent need for the search of antimicrobial substances which target disruption of...

Molecules that target quorum sensing and biofilm inhibition are useful antimicrobials. In this regard, a new diarylhydrazone was synthesized and characterized using infrared, high-resolution mass spectrometry and nuclear magnetic resonance experiments as N-[( E)-4-bromo-2,5-diheptyloxybenzylideneamino]-2,4-dinitroaniline (BHBANA). Minimal inhibitor...

Graptophyllum pictum is a tropical plant noticeable for its variegated leaves and exploited for various medicinal purposes. In this study, seven compounds, including three furanolabdane diterpenoids, i.e., Hypopurin E, Hypopurin A and Hypopurin B, as well as with Lupeol, β-sitosterol 3-O-β-d-glucopyranoside, stigmasterol 3-O-β-d-glucopyranoside and...

Skin diseases can get natural therapies from medicinal plant-based products. In this study, a topical cream was formulated from ethanol extract of Acacia sieberiana, beeswax and Vitellaria paradoxa (shea) butter. GC-MS characterization with co-injection of the topical cream revealed Stearic acid (31.43%), Palmitic acid (23.15%), Oleic acid (21.44%)...

Microbial resistance is facilitated by biofilm formation and quorum-sensing mediated processes. In this work, the stem bark (ZM) and fruit extracts (ZMFT) of Zanthoxylum gilletii were subjected to column chromatography and afforded lupeol (1), 2,3-epoxy-6,7-methylenedioxyconiferyl alcohol (3), nitidine chloride (4), nitidine (7), sucrose (6) and si...

From Rinorea oblongifolia fruits, 3-Nor-4β-friedelan-24-ol (1) and 3-decyl-6,7,8-trimethoxy-2H,5H-furo[4,3,2-de]isochromene-2,5-dione (4), new derivatives alongside, 28-hydroxyfriedelan-3-one (2), friedelin (3), 3,3',4,4',5'-pentamethylcoruleoellagic acid (5), hexamethylcoruleoellagic acid (6), 3',4,4',5,5'-pentamethylcoruleoellagic acid (7), and f...

The current study was conducted to isolate the phytoconstituents from Erythrina senegalensis leaves and stem bark and evaluate their inhibitory activity against α-glucosidase, digestive enzyme related to diabetes mellitus. Phytochemical investigation of the leaves resulted in the isolation of three saponins (3-5), two triterpenoids (7 and 8) and tw...

Transmission of infectious diseases and resistance by microorganisms is a global health threat. Antimicrobial polymers are increasingly being developed as biocides with greater applications than traditional antibiotics. In this study, 3‐(potassiumsulfonyl)propyl methacrylate (SPMA) monomer, ethylene glycol dimethacrylate cross‐linker and ammonium p...

Aim. This study is aimed at establishing phenolic compound profile and assessing the possible antiulcer activities of aqueous extracts of some staple plant foods from the West and North-West regions of Cameroon against chronic gastric ulcer models in rats. Materials and Methods. Phenolic constituents of extracts were evaluated using HPLC-DAD. Aqueo...

Five extracts were prepared from different propolis samples and denoted PR1-PR5. They were subjected to two complementary antioxidant assays, DPPH radical scavenging and metal chelation. The propolis extracts PR4 and PR5 showed good radical scavenging power with IC50 20.45 ± 1.65 μg/mL and 17.23 ± 1.40 μg/mL respectively as well as appreciable chel...

Diabetes mellitus is a metabolic disorder which is one of the leading causes of mortality and morbidities in elderly humans. Chronic diabetes can lead to kidney failure, blindness, limb amputation, heart attack and stroke. Physical activity, healthy diets and medications can reduce the incidence of diabetes, so the search for more efficient antidia...

The virulence and resistance of pathogenic microorganisms are promoted by quorum-sensing (QS) mediated traits and biofilms. The development of antimicrobial agents which can reduce the incidence of microbial resistance by disrupting the establishment of biofilms and QS, constitute a suitable strategy to reduce the emergence of pathogenic strains th...

Gum arabica is a local commercial nutraceutical and food preservative collected mostly from acacia plants. HPLC-DAD analysis identified gallic acid, syringic acid, ferulic acid, coumarin, rutin and rosmarinic acid in hydroethanol extracts of all three acacia species with ferulic acid being the most abundant component in Acacia ataxacantha (45.25 ±...

Phytochemical study of the aquatic plant Dicraeanthus zehnderi H. Hess., led to the isolation of eleven compounds, including one alkaloid [2′-acetamido-3′-phenylpropyl-2-benzamido-3-phenylpropionate (1)], one fatty alcohol [Tridecanol (2)] and nine known xanthones [Caloxanthone A (3), Caloxanthone C (4), Trapezifoliaxanthone (5), 1,7-dihydroxyxanth...

Propolis is very popular for its beneficial health properties, such as antimicrobial activity and antioxidant effects. It is one of the most long-serving traditional medicines to mankind due to its interesting chemical diversity and therapeutic properties. The detailed chemical information of propolis samples is very necessary to guarantee its safe...

Arab Y, Sahin B, Ceylan O, Zellagui A, Olmez OT, Kucukaydin S, Tamfu AN, Ozturk M, Gherraf N. 2022. Assessment of in vitro activities and chemical profiling of Senecio hoggariensis growing in Algerian Sahara. Biodiversitas 23: 3498-3506. The in vitro antioxidant, anticholinesterase, tyrosinase inhibitory, antibiofilm, and anti-quorum sensing activi...

The phytochemical investigation of the DCM/MeOH (1:1) extract of the fruits of Cnestis ferruginea led to the isolation and characterization of one new quinic acid derivative, ferruginoic acid (1), together with six known compounds 2-7. Compounds 3-7 were reported for the first time from this species. The structures of compounds 1-7 were elucidated...

Diabetes as well as the enhanced microbial multidrug resistance resulting from biofilm formation, constitutes some of the major health problems around the world. Triterpenoids and their derivatives have been shown to have a great contribution in this domain. A small library of benzoyl esters of lupeol and β-amyrin was synthesized and their structur...

Phenolic compounds constitute a class of bioactive metabolites whose extraction from plants, characterization and medicinal applications are of significant importance. Phenolic extracts were prepared from Syringa vulgaris, Citrus sinensis and Hypericum perforatum by ultra-sound assisted extraction with ethanol:water (70%) as solvent. Using HPLC–DAD...

Medicinal plants from Chad grow under special climatic conditions in between the equatorial forest of Central Africa and the desert of North Africa and are understudied. Three medicinal plants from Chad (T. diversifolia, P. Biglobosa and C. Febrifuga) were evaluated for their phenolic composition, antioxidant and enzyme inhibition activities. The t...

Two phytosphingosine-type ceramides (euclinide A (1) and B (2)) were isolated alongside one fatty acid (geddic acid (3)), one fatty acid-1-glyceride ((2 S)-1- O-hentriacontanoyl glycerol (4)), ten triterpenes ( α-amyrin (5), α-amyrin acetate (6), ursolic acid (7), β-amyrin (8), β-amyrin acetate (9), β-amyrin palmitate (10), oleanic acid (11), masli...

18β-Glycyrrhetinic acid (18β-GA) is known for several biological activities, and has been the focus of extensive research for the development of new therapeutic agents. In the current study, 18β-GA-peptide conjugates 2−11 were evaluated for their in vitro α-glucosidase inhibitory and antiglycation activity. Structure-activity relationship (SAR) est...

In this study, Melaleuca alternifolia (Maiden and Betche) Cheel (tea tree) oil and C. sinensis (L.) Osbeck (orange) oil was procured, and their chemical compositions were characterized by gas chromatography coupled with mass spectrometry, with co-injection using authentic samples. The oils were rich in monoterpene hydrocarbons making up 84.5% of C....

Phytochemical study of the roots of Erythrina senegalensis led to the isolation of a new α-sophoradiol glycoside, erythrinoside (1), together with four known compounds, lupeol (2), α-sophoradiol (3), isoneorautenol (4) and D-mannitol (5). The structures of the compounds were elucidated using spectroscopic data including 1D and 2D NMR, mass spectrom...

A new abietane-type diterpenoid, rubesanolidic acid (1), alongside six known compounds including β-sitosterol (2), lupeol (3), betulinic acid (4) ursolic acid (5), β-sitosterol 3-O-β-D-glucopyranoside (6) and stigmasterol 3-O-β-D-glucopyranoside (7) were isolated from the roots of Burkea africana through column chromatography. Their structures were...

Alzheimer’s disease (AD) is a severe neurodegenerative disorder of different brain regions accompanied by distresses and affecting more than 25 million people in the world. This progressive brain deterioration affects the central nervous system and has negative impacts on a patient’s daily activities such as memory impairment. The most important ch...

Phenolic extracts of Clinopodium nepeta were prepared and their preliminary phenolic profiles determined using HPLC-DAD with 26 phenolic standards. Apigenin (21.75 ± 0.41 µg/g), myri-cetin (72.58 ± 0.57 µg/g), and rosmarinic acid (88.51 ± 0.55 µg/g) were the most abundant compounds in DCM (dichloromethane), AcOEt (ethyl acetate), and BuOH (butanol)...

The present study reports the chemical constituents, antioxidant, anticonvulsant and α-amylase activities of the aerial part of Cyperus rotundus collected in Cameroon. Phytochemical study leads to the isolation of six known compounds alongwith lupeol (1), stigmasterol (2), tetracosanoic acid (3), a mixture of β-sitosterol (4a) and stigmasterol (4b)...

The chemical composition of essential oils (EOs) extracted from the aerial parts of 2 species of Juniperus was determined by Gas Chromatography-Mass Spectrometry (GC-MS). In total, 65 and 58 compounds accounting for 90.3% and 89.8% of the whole chemical composition of Juniperus oxycedrus (JO) and Juniperus phoenicea (JP) were identified, respective...

Cinnamomum zeylanicum and Ocimum basilicum are two plants used by many cultures for food and medicinal purposes. The phenolic composition of ethanol extracts of both plants were determined by HPLC–DAD. A total of seventeen compounds were identified in C. zeylanicum with trans cinnamic acid (179.90 ± 0.45 µg/g) and coumarin (84.50 ± 0.41 µg/g) as ma...

Medicinal food excipients can be used to combat microbial infections especially essential oils. Xylopia aethiopica (Dunal) A. Rich is a highly consumed medicinal food spice in Africa and its seeds essential oil was extracted by hydro-distillation and characterized by GC-FID and GC-MS. Its antimicrobial, anti-biofilm, anti-motility and quorum sensin...

Recently, the honey and propolis of stingless bees have been attracting growing attention because of their health-promoting properties. However, studies on these products of African Meliponini are still very scarce. In this preliminary study, we analyzed the chemical composition of honey, two cerumen, and two resin deposits (propolis) samples of Me...

In this work, poly(glycidyl methacrylate) (PGMA, G) homopolymers with different molecular weights (5600–21,000 gmol⁻¹) were synthesized by atom transfer radical polymerization (ATRP) method. Epoxy groups of PGMA homopolymers were converted to hydroxyl and 1‐methyl piperazin residues by reacting with 1‐methyl piperazine via ring‐opening reaction. Th...

Aim: To compare the phytochemicals and antimicrobial activities of Pterocarpus mildbraedii Harms and Xylopia aethiopica(Dual) A.Rich Methodology: The leaves of P. mildbraedii and X. aethiopica were collected, washed, air-dried, ground and each extracted with n-hexane, ethyl acetate and methanol. The extracts were analysed for the presence of phytoc...

Food pathogens represent an important health threat, and it is relevant to study the effect of foodstuffs such as spices which can inhibit bacterial growth. This study reports the antimicrobial, antibiofilm, and enzyme (Acetylcholinesterase, Butyrylcholinesterase, urease, tyrosinase) inhibitory activities of two medicinal food spices belonging to t...

Phytochemical study of Uvaria comperei afforded an alkaloid, 8,9-dimethoxy-5H-phenanthridin-6-one (1), isolated and characterised (assignment of ¹H and ¹³C NMR) for the first time from a natural source along with two flavonoids, (2S)-5-hydroxy-7,8-dimethoxyflavanone (2) and (2S)-7-hydroxy-5-methoxy-6,8-dimethylflavone (3). Clethric acid (4), oleano...

This study was aimed at synthesizing polyethyleneimine-coated magnetic nanoparticles and evaluating their effect on pathogenic bacteria. Polyethyleneimine-coated magnetite (PEIMnF) and nickel ferrite (PEINF) nanoparticles were succesfully synthesized and their surface groups, morphology and chemical structures were characterized using ATR-FTIR (Att...

This study aimed at investigating phenolic composition, anti-quorum sensing and enzyme inhibitory potential of Camellia sinensis and Curcuma longa. HPLC-DAD identified and quantified curcumin (398.67 ± 0.34 mg/g), demethoxycurcumin (261.39 ± 0.27 mg/g) and bisdemethoxycurcumin (173.32 ± 0.46 mg/g) in C. longa extract and eight phenolics in C. sinen...

Background : The discovery of novel phytochemicals represents a reasonable approach to fight malignancies, especially those which are resistant to standard chemotherapy. Purpose : We evaluated the cytotoxic potential of a naturally occurring N-acetylglycoside of oleanolic acid, aridanin, on 18 cancer cell lines, including sensitive and drug-resist...

The aim of this work was to evaluate in vitro antiradical scavenging activity of propolis from Nkambe (North-West, Cameroon). The polyphenol content of the acetone extract was evaluated using the Folin-Ciocalteu reagent as 0.166±0.008 gGAE/100 gRM. Antiradical scavenging activity of hexane and acetone extracts was carried out on DPPH using ascorbic...

The increasing resistance of bacteria to antibiotics has motivated the interest in potent natural compounds capable of disrupting bacterial cell-to-cell communication. Column chromatography of seed extract of Annona senegalensis afforded N-cerotoyltryptamine (1), asimicin (2) and ent-19-carbomethoxykauran-17-oic acid (3). The compounds were tested...

Propolis is rich in diverse bioactive compounds. Propolis samples were collected from three localities of Cameroon and used in the study. Column chromatography separation of propolis MeOH:DCM (50:50) extracts yielded a new isoflavonol, 2-hydroxy-8-prenylbiochanin A (1) alongside 2’,3’-dihydroxypropyltetraeicosanoate (2) and triacontyl p-coumarate (...

Considering the large consumption of Afrostyrax Lepidophyllus seeds, chemical analyses is necessary to ascertain its use as food spice and also its medicinal potential. Inductively coupled plasma mass spectrometry and gas chromatography mass spectrometry were used to evaluate the mineral and volatile contents respectively while column chromatograph...

Column chromatography led to the isolation and full characterization of N-cerotoyltryptamine (1) previously described in a mixture of 5 compounds, asimicin (2) and ent-19-Carbomethoxykauran-17-oic acid (3) isolated from this species for first time alongside stigmasterol glycoside (4) and lacceroic acid (5). The structures of the compounds were esta...

The extracts of some propolis samples were analysed by GC-MS and then purified by column chromatography. The latter led to the isolation of a new mono-ether of glycerol, 1'-O-eicosanyl glycerol and a new triterpene, methyl-3β,27-dihydroxycycloart-24-en-26-oate together with known triterpenoids namely betulin, 3β-hydroxylanostan-9,24-dien-21-oic aci...

Three extracts of propolis harvested from Nkambe, North-West region of Cameroon were characterized by GC-MS analysis and their gastric cytoprotective, antisecretory and antioxidant properties evaluated using experimentally-induced gastric ulcers in rats. The propolis extracts were rich in phytoconstituents occurring as sugars, triterpenes and a mix...

Five extracts of propolis of Adamawa Cameroon were obtained by percolation and maceration with five different solvents: hexane, ethyl acetate, ethanol, methanol and water, in order of increasing polarity. Phytochemical screening was carried out on the extracts and the total content in flavonoids and polyphenols were evaluated by photometric methods...