Papers by Jean-Paul Koto-te-Nyiwa Ngbolua
Aims: To valorize traditional foods of the Democratic Republic of Congo in general and the provin... more Aims: To valorize traditional foods of the Democratic Republic of Congo in general and the province of Bandundu in particular by evaluating the antioxidant activity of five species of Dioscorea, the determination of their chemical composition as well the determination of their glycemic index. Study Design: Survey; plant collection and identification, phytochemical and biological evaluation: 2 phytochemical screening, proximate analyses, in vitro and in vivo assays. Place and Duration of Study: " Université de Kinshasa " (DR Congo), from February 2013 to December 2015. Methodology: The anti-diabetic activity was carried out in vivo using an animal model (NMRI mice), by administration of a solution of glucose (200 mg/mL). Antioxidant activity was evaluated using the ABTS and DPPH assays. The micrographic analysis of the flours of the studied species showed that their starch grains are characteristic of each species by their size, their form and the position of the hila and the presence of the scratches. Results: All extracts of Dioscorea displayed highest ABTS and DPPH radical-scavenging activities (IC 50 <1 mg/mL) related to their appreciable amount of total phenolic contents. Total phenolic contents expressed as mg of gallic acid equivalent per gram of dried extract are ranged from 9.85±0.098 to 51.12±0.500. Only Dioscorea bulbifera contains flavonoids expressed as 3.33±0.23 mg of quercetin equivalent. These yams showed a good antihypergycemic activity, Dioscorea praehensilis and Dioscorea bulbifera showed a glucose reduction rate of 54.0% and 51.3% after 30 min respectively. Conclusion: The results obtained show that Dioscorea tubers species studied have a high food value and thus can be developed as functional food.
Annals of African medicine
Annals of African medicine
Lepira FB, Kayembe PK, M'Buyamba-Kabangu JR. Etude par spectroscopie UV-visible de la dénaturatio... more Lepira FB, Kayembe PK, M'Buyamba-Kabangu JR. Etude par spectroscopie UV-visible de la dénaturation thermique de l'hémoglobine S : une nouvelle approche du dépistage rapide de la drépanocytose
Madagascar est une grande île de l’Océan Indien présentant toutes les caractéristiques d’un petit... more Madagascar est une grande île de l’Océan Indien présentant toutes les caractéristiques d’un petit continent et a un renom mondial pour son exceptionnel biodiversité par son taux d’endémisme élevé. Du point de vue écologique, Madagascar est une unité biogéographique comportant plusieurs écorégions. Sa flore présente un intérêt scientifique tout particulier en raison de sa diversité, de son ancienneté et de sa très grande richesse. A cet effet, ce « hot spot » de la biodiversité constitue une zone de choix pour la recherche de nouvelles molécules d’intérêt biopharmaceutique. La présente communication va passer en revue quelques métabolites secondaires d’intérêt biopharmaceutique isolé des plantes endémiques de Madagascar et les enjeux du développement durable du point de vue social, économique et environnemental liés à l’exploitation de ces ressources biologiques. Mots clés : Biodiversité, Substances naturelles, Développement durable, Madagascar.
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A study on the cultivation techniques on cassava has been carried out in Yangambi. Four cultivati... more A study on the cultivation techniques on cassava has been carried out in Yangambi. Four cultivation practices: polling, thinning, combination of polling and thinning and the control (neither thinning nor polling), have been applied on four selected varieties of cassava namely: N'sansi, Zizila, Butamu and a local one called Mbongo. The results obtained revealed that there is no significant differences between these techniques precisely on the tuber production of these varieties which are differently produced. These yields have been of 21.7 t/ha for Butamu; 28.6 t/ha for N'sansi; 20.2 t/ha for Zizila and 13.5 t/ha for Mbongo (the local variety). The overall results of this study show that polling and thinning combined techniques can be used for the improvement of the cassava productivity in Yangambi city. .
Rainfall is natural climatic phenomena for which prediction constitutes a great challenge nowaday... more Rainfall is natural climatic phenomena for which prediction constitutes a great challenge nowadays. Its forecast is of particular relevance to agriculture and medicinal plants growth and development, which contribute significantly to the economy of Africa. Rainfall is highly non-linear and complicated phenomena, which require mathematical modelling and simulation for its accurate prediction. The present study examined the monthly precipitation using the Box-Jenkins methodology. The monthly precipitations data were collected from Binza Meteorological station of Kinshasa (Democratic Republic of the Congo) during the year 1970 to 2009. The results of the estimated parameters revealed that ARIMA (5, 1, 1) model is appropriate for the series. In the first analysis, we standardized this time series, then we have modeled the resulting series by model ARIMA (5, 1,1). In the second analysis, we carried out a modeling of these quantities using ARIMA model according to three processes: Identif...
Recent findings indicate that Non-human primates (NHP) serve as important reservoirs of parasites... more Recent findings indicate that Non-human primates (NHP) serve as important reservoirs of parasites that cause diseases to man as close interactions between humans and NHP create pathways for the cross-species transmission of common zoonotic diseases. The present study was carried out with the aim of investigating the intestinal helminthes infestation in two wild species of Galagos: Galagoides demidovii and Sciurocheirus gabonensis. Stool samples collected from 30 specimens were examined from March to July 2012 using direct wet mount, concentration via sodium chloride floatation and sedimentation methods. Identification of parasitic ova was carried out according to an established protocol. Results indicated that Hymenolepis nana had the highest infestation rate (55.56%), followed by Taenia sp. (51.85%) and Ascaris lumbricoides (37.04%) in species from “N’djili brasserie” site while for the samples from Luki, Teania sp. displayed a highest prevalence rate (75%) flowed by Ancylostoma du...
Cassava (Manihot esculenta Crantz) is an important food crop in Democratic Republic of the Congo.... more Cassava (Manihot esculenta Crantz) is an important food crop in Democratic Republic of the Congo. It is a tuberous crop that produces long and tapered storage roots that are a major source of energy and carbohydrates. Depending on the cultivars and growing conditions, these large storage roots are harvested 6 to 24 months after planting. The present study was conducted under agro-ecological conditions of Gbadolite city during 12 months in order to evaluate the effect of cassava sample cuttings area on the yields of tuber roots. The results revealed that the yields were 15.33; 16.40 and 15.60 t/ha for the base cuttings, middle and top cuttings respectively. This indicates that the sampling area does not affect cassava tuber roots production (p>0.05), and means that all the cassava stems can be used as propagating material in the District of Nord Ubangi. For the best of our knowledge, this is the first time report on such research in the District of Nord Ubangi. Keyword: Manihot es...
The goal of present study, carried out at Gbadolite city, was to incorporate the papaya leaves fl... more The goal of present study, carried out at Gbadolite city, was to incorporate the papaya leaves flour into the food diet of chicks from 0 to 8 weeks and to evaluate its effects on some zootechnical parameters. We used one day-80 non sexed chicks from the artisanal incubator. Those chicks have been divided in two groups: the first group with 40 chicks fed with the diet incorporating papaya leaves flour (Carica papaya L.) (L1) and the second group with 40 others chicks fed with the diet lacking the aforementioned flour and served as control (L0). The obtained results indicated that papaya leaves flour based diet was more provided (1337.5 g) than the control diet (1025 g); The test diet (L1) had brought about fewer cases of mortality (10%) than the control diet (L0) (17%); The diet enriched with the Carica papaya L. flour is quite better according to its consumption index (1.4 versus 1.6 for control diet); The test diet (L1) has favored more medium live weight (156.7 g) and average live...
Fatty acids C20-C26 are important for use in oleo-chemical industry whereas they also allow asses... more Fatty acids C20-C26 are important for use in oleo-chemical industry whereas they also allow assessing chemotaxonomic relationships among plant taxa. There are however, comparatively few common vegetable fats which contain them in appreciable amounts.Using gas chromatography this type of very long-chain fatty acids was analyzed in oils from Pentaclethra macrophylla (Fabaceae), Millettia dura (Fabaceae), Tephrosia vogelii (Fabaceae),Cardiospermum halicacabum (Sapindaceae), Maesopsis eminii (Rhamnaceae), Podocarpus usambarensis (Podocarpaceae) and Myrianthus arboreus and M. holstii (Moraceae),wild plant species from Kahuzi-Biega National Park and adjacent areas in D.R. Congo. These plants are used by the local population mainly for nutrition and medical purposes.The percentage of very-long chain fatty acids in the analyzed oils ranged from 1.2 to 21.3%. P. macrophylla revealed the highest rate and M. holstii showed the lowest rate. These acids consist of arachidic, eicosenoic, eicosadi...
In the present work, anthocyanins extracts from a Congolese plant Morinda lucida were evaluated f... more In the present work, anthocyanins extracts from a Congolese plant Morinda lucida were evaluated for their antisickling activity using microscopic technique. The red blood cells (RBCs) were observed to change from the sickled shape to normal biconcave cells in the presence of 2 per cent sodium metabisulfite. The treated SS RBCs demonstrated a remarkable similarity to normal blood values (Radius =3.3±0.3mm).The minimal concentration of normalization (MCN) of sickle cell erythrocytes was 0.195 μg/mL. The antisickling activity was found to be dose dependent. Anthocyanins extracts was found to be responsible of the inhibition of the sickling process, thus, justifying the claims of the traditional medical practitioners and suggesting a possible correlation between the chemical composition of this plant and its use in traditional medicine.
Oxidative stress is considered to be the common pathway linking the various mechanisms of the pat... more Oxidative stress is considered to be the common pathway linking the various mechanisms of the pathogenesis of diabetic complications, thus in the management of diabetes, It is better to have drugs which are fighting at the same time against diabetes and oxidative stress. The plants used in Congolese Traditional Medicine have a great medicinal potential and may be candidates for new antidiabetic and antioxidants. It is in this context that we have focused our interest on Isolona hexaloba which has been reported to possess a number of medicinal properties. The present study was undertaken to evaluate the antioxidant (DPPH scavenging) and antihyperglycemic (glucoseoverloaded hyperglycemic rats models at dose levels of 200 and 400 mg/kg bw.) activities. The total extract has the higher antioxidant activity (IC50 = 1.24 ± 0.04 μg/ml)); methanol fraction showed a significant reduction in fasting blood glucose levels when compared to the standard drug, oral Glibenclamide (5 mg/kg bw). For ...
The use of medicinal plants for the treatment and prevention of human diseases including Sickle c... more The use of medicinal plants for the treatment and prevention of human diseases including Sickle cell disease is an old indigenous technology in Africa. Pentaclethra macrophylla is traditionally used in Congolese folk medicine to treat Sickle Cell Disease. The aim of the present study was to evaluate the antisickling and radical scavenging activities of Pentaclethra macrophylla stem bark using Emmel’s test and the radical DPPH assay. The results showed that n-hexane, dichloromethane and methanol soluble fractions exhibited interesting antisickling activity compared to that of ethyl acetate soluble fraction, as revealed by the observed normal biconcave form of sickle erythrocyte in hypoxic conditions. On the other hand, the ethyl acetate and methanol soluble fractions revealed a significant radical scavenging activity. The methanol soluble fraction exhibited a promising antiradical activity (IC50 = 1.517 ± 0.053 µg/mL). The chemical screening performed on this plant species revealed t...
Anthocleista liebrechtsiana is a plant species widely used in traditional medicine to treat bacte... more Anthocleista liebrechtsiana is a plant species widely used in traditional medicine to treat bacterial infections. To provide a scientific basis to traditional uses of this plant species, it different extracts were evaluated for their antibacterial and antioxidant potential. Antibacterial activity was assessed using minimum inhibitory concentration. The presence of phytoconstituents was detected qualitatively. A. liebrechtsiana extracts displayed interesting antibacterial and antioxidant activities. The Gram positive bacteria S. aureus ATCC 33591 were more sensitive to Anthocleista liebrechtsiana than the Gram negative E. coli ATCC 27195. All the extracts tested were found to be biologically active against Staphyloccocus aureus except alcoholic extract of the leaves for which the bioactivity was moderate. The antibacterial activity was marked for the stem bark extracts (MIC ≤ 31.5 μg/mL) than those of the leaves (MIC ≤ 62.5 μg/mL). Methanol extract of A. liebrechtsiana displayed also...
The Okapi is an endemic species of the Democratic Republic of the Congo and is the national conse... more The Okapi is an endemic species of the Democratic Republic of the Congo and is the national conservation symbol of the country. Because of poaching and the repetitive civil wars in the eastern part of the DRC, identifying new naturally occurring habitat of Okapi in others part of the country is a great challenges for the conservation of this great mammalian. The present communication gives for the first time the evidence of new geographic localization of Okapia johnstoni in the rainforest of “Nord Ubangi” district. The district is politically very stable, thus justifying the need to initiate a project for in situ conservation of Okapi in this area. Keyword: Okapia johnstoni, Nord Ubangi, Democratic Republic of the Congo
Zoo-pharmacognosy is a mean by which animal self-heal by using of plants and invertebrates. Becau... more Zoo-pharmacognosy is a mean by which animal self-heal by using of plants and invertebrates. Because of their phylogenetic closeness and common neural pathways of chemosensory perception, humans and great apes, when displaying symptoms of illness learn to select some biological resources as medicine: e.g. diplopods secretions is used by great apes to heal against various skin bacterial infectious diseases which are also recurrent pathologies of the SCD. The present study evaluated the antisickling and antimicrobial activities of organic acids and alkaloids extracted from a Congolese diplopod using Emmel test and micro-dilution technique respectively. The chemical screening performed on the diplopods extract revealed the presence of phenolic compounds, alkaloids, quinones, terpenoids and organic acids. The results of bioassays revealed that organic acids and alkaloids crude extracts possess promising antisickling and antibacterial activities in vitro as revealed by both the observed n...
The plant species Anthocleista schweinfurthii is eaten by bonobos, an endemic pygmy chimpanzee of... more The plant species Anthocleista schweinfurthii is eaten by bonobos, an endemic pygmy chimpanzee of Democratic Republic of the Congo and also used in folk medicine to treat bacterial diseases. To provide a scientific basis to traditional uses, the plant species was screened for it antibacterial and antioxidant potential. Antibacterial activity was assessed by minimum inhibitory concentration method. The presence of phytoconstituents was evaluated qualitatively. A. schweinfurthii extracts displayed interesting antibacterial and antioxidant activities. The Gram positive bacteria S. aureus ATCC 33591 were more sensitive to A. schweinfurthii than the Gram negative E. coli ATCC 27195. The stem bark extracts and n-hexane fraction of the leaves were found to be biologically active against Staphyloccocus aureus ATCC 33591 strains (MIC ≤ 62, 5 μg/mL) while, the bioactivity of dichloromethane, ethyl acetate and methanol soluble fractions of the leaves was moderate (MIC > 100 μg/mL). The meth...
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Papers by Jean-Paul Koto-te-Nyiwa Ngbolua