An overview of anti-diabetic plants used in Gabon: Pharmacology and Toxicology

© 2017 Elsevier B.V. All rights reserved.Ethnopharmacological relevance: The management of diabetes mellitus management in African communities, especially in Gabon, is not well established as more than 60% of population rely on traditional treatments as primary healthcare. The aim of this review was to collect and present the scientific evidence for the use of medicinal plants that are in currect by Gabonese traditional healers to manage diabetes or hyperglycaemia based here on the pharmacological and toxicological profiles of plants with anti-diabetic activity. There are presented in order to promote their therapeutic value, ensure a safer use by population and provide some bases for further study on high potential plants reviewed. Materials and methods: Ethnobotanical studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals. Keywords including ‘Diabetes’ ‘Gabon’ ‘Toxicity’ ‘Constituents’ ‘hyperglycaemia’ were used. Results: A total of 69 plants currently used in Gabon with potential anti-diabetic activity have been identified in the literature, all of which have been used in in vivo or in vitro studies. Most of the plants have been studied in human or animal models for their ability to reduce blood glucose, stimulate insulin secretion or inhibit carbohydrates enzymes. Active substances have been identified in 12 out of 69 plants outlined in this review, these include Allium cepa and Tabernanthe iboga. Only eight plants have their active substances tested for anti-diabetic activity and are suitables for further investigation. Toxicological data is scarce and is dose-related to the functional parameters of major organs such as kidney and liver. Conclusion: An in-depth understanding on the pharmacology and toxicology of Gabonese anti-diabetic plants is lacking yet there is a great scope for new treatments. With further research, the use of Gabonese anti-diabetic plants is important to ensure the safety of the diabetic patients in Gabon.Peer reviewedFinal Accepted Versio

In vitro antimicrobial activity of Harungana madagascriensis and Euphorbia prostrata extracts against some pathogenic Salmonella sp.

Harungana madagascariensis Lam (Hypericaceae) and Euphorbia prostrata Ait (Euphorbiaceae) are commonly used in Cameroon as traditional medicines for the treatment of typhoid fevers. Aqueous extracts were prepared from the leaves of H. madagascariensis and the whole plant of E. prostrata and tested in vitro for antibacterial activity against Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B and Salmonella Typhimurium, using broth dilution technique. Phytochemical screening was performed using standard methods. Acute toxicity study of the various extracts was also done on mice. Results obtained showed that H. madagascariensis extract exhibited minimum inhibitory concentrations (MICs) ranging from 390.625 to 1562.5 μg/ml. The median lethal dose (LD50) of H. madagascariensis extract as shown by the acute toxicity studies were 11.6 g/kg and 13.2 g/kg body weight for female and male mice, respectively. The MIC values of E. prostrata extract varied from 1024 to 2048 μg/ml. The LD50 values obtained for this extract were 23.2 g/kg and 26.4 g/kg body weight for female and male mice, respectively. Phytochemical analysis showed the presence of phenols, tannins, saponins, anthraquinones, anthocyanins, triterpenoids, flavonoids and alkaloids in both plant extracts. These data suggest that the aqueous extracts of H. madagascariensis and E. prostrata contain antibacterial principles which may be non toxic.Keywords: Harungana madagascariensis, Euphorbia prostrata, antibacterial activity, Salmonella sp., phytochemical screening, acute toxicity

Risk factors of cervical intraepithelial lesion in Douala-Cameroon: Implications of Herpes Simplex Virus Type 2, Chlamydia Trachomatis and Treponema Pallidum

Infection with high risk oncogenic human papillomavirus (HPV) such as HPVs 16 and 18 is the main cause of cervical cancer. The objective of this study was to determine the impact of Chlamydia trachomatis, Herpes simplex virus 2 (HSV 2), Treponema pallidum and some sexual behaviour on malignant progression of cervical lesion in Douala, Cameroon. From July 2009 to January 2010, we performed routine cervical smears to 163 consenting women, who completed a questionnaire on risk factors of cervical cancer. Blood samples were obtained for each of these women and used for the detection of antibodies against Chlamydia trachomatis, HSV 2 and Treponema pallidum. Results obtained showed that 26/163 (17 LSIL and 9 HSIL) of women had abnormal cytology, 75.5% (123/163) had HSV 2 infection, 19% (31/163) infected by Chlamydia trachomatis and 4.3% (7/163) infected by Treponema pallidum. Among the LSIL-positive women 35.3% (6/17) and 94.1% (16/17) were infected with Chlamydia trachomatis and HSV 2 respectively. Among those with HSIL cytology, 22.2% (2/9), 66.7% (6/9) and 11.1% (1/9) respectively had Chlamydia trachomatis, HSV 2 and Treponema pallidum. High parity and pregnancy rate was observed among women with positive cytology. Our finding shown high rate of cervical abnormalities among women infected with HSV 2; and among those with a higher number of parities and pregnancies. These results suggest that further investigations should be made in Cameroon to access real burden of these risk factors in the progression and persistence of cervical lesion.Key words:risk factors, cervical cancer, HSV 2, Chlamydia trachomatis, sexually transmitted infections.doi: 10.4314/ajcem.v12i3.

ASSESSMENT OF THE ADSORPTION OF AEROMONAS HYDROPHILA ON POLYTHENE IN SODIUM HYPOCHLORITE AND HYDROGEN PEROXIDE TREATED WATER

A study was carried out on Aeromonas hydrophila adhesion to polythene fragment at different cell growth phases in aquatic microcosm. The main purpose of this study was to assess adsorption capacity, adsorption intensity and kinetics of Aeromonas hydrophila on polythene in sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2) disinfected water. The mean abundance of adhered A. hydrophila sometimes reached 28 and 111CFU.cm-2 respectively in NaOCl and H2O2 treated water. The adsorption capacities of A. hydrophila cells fluctuated between 1 and 2.12x1057 and between 1 and 2.29x1027 adhered cells.cm-2 in NaOCl and H2O2 disinfected water respectively. The adsorption intensities of this bacterium ranged from -45.81 to 3.49x1019 and from 0.16 to 2.29x1027 respectively in NaOCl and H2O2 treated water. Adsorption capacity and adsorption intensity of A. hydrophila cells on polythene in NaOCl treated water were greater than that obtained in water disinfected with H2O2. Adhesion kinetics of A. hydrophila cells oscillated between 0.001 and 0.930 adhered cell.cm-2.h-1. Adsorption kinetics seem resulted from interactions between bacterial cells and substrates, and depended both on the fragment type and bacterial species. The values of A. hydrophila surface hydrophobicity fluctuated between 65.11 and 92.74% in NaOCl disinfected water and between 63.38 and 89.41% in H2O2 treated water. The mean values of contact angle ranged from 83.1±0.6 to 85.8±0.8°.   Adhesion of A. hydrophila on polythene is mediated amongst others by cell growth phases, cell surface hydrophobicity, cell kinetic adhesion, adsorption capacity and adsorption intensity

Assessment of the potential effect of some streams properties on the isolated Aeromonas hydrophila strains susceptibility against some β-Lactams and Sulfamids

The isolation and characterization of A. hydrophila strains were carried out a given stream located in the equatorial zone in Cameroon (Central Africa), during the mild rainy season and the mild dry season. The water physicochemical parameters measured were temperature, pH, electrical conductivity, color, turbidity and suspended solids. It has been noted that bacterial abundances as well as the values of physicochemical parameters undergoes temporal variations. Antimicrobial susceptibility tests showed that the means diameters of inhibition with Oxacillin, Ceftriazone, Penicellin, Sulfamethoxazol-trimethoprim, Chloramphenicol, Imipenem, Amoxicillin-Clavulanic acid and Cefazolin were 6.44, 21, 6.63, 9.58, 15.37, 22.18, 14.29 and 10.26 mm respectively. 100% of strains tested were resistant to Penicillin, 89.47 % resistant to Oxacillin, 68.42% resistant to Sulphamethoxazole-trimetroprim and 63.15% were resistant to Cefazolin. There were 54.60% cases of antibiotic resistance, 24.34 % of intermediate sensitivity and 21.05% of sensitive strains against the tested antibiotics. The encoded redundancy analysis indicates that the percentage of the variation explained on the canonical axes is of 47.8% for the F1 axis and 25.9% for the F2 axis, for an accumulated percentage of 73.7%. The suspended solids, the Ceftriazon and Chloramphenicol are correlated to the F1 axis in positive coordinates, and the Temperature and Amoxicillin-Clavulanic acid in negative coordinates. The correlation test between the water physicochemical characteristics and the inhibition diameters of antibiotics showed some significant correlations (P<0.05). The regulation of bacterial genes would be regulated by complex mechanisms. Although many factors implied are linked to the bacterial cell, others may belong to the closed environment

Écritures Romanesques Africaines Et Construction D'Une Conscience Historique En Contexte Postcolonial

Electronic Thesis or DissertationThis work explores how the memory of Cameroon's independence war is written in the works of some Cameroonian writers. Through their novels, those writers, born at different periods in Cameroon's history and living in different contexts, raise contemporary political issues. The gradual opening up of French colonial and military archives, the apparent willingness of Cameroonian and French politicians to open the debate on who was responsible for the massacres during Cameroon's war of liberation, and above all the progress made in the field of research into this period of Cameroonian history, have given rise to a body of French-speaking African literature that reinvests the field of history to narrate a critical moment in the political development of this Central African country. Using Halbwachs' approach to the construction of national identities through memory, we can see that, by investing the field of history and memory, these novels mobilize a certain number of artistic strategies that, in fact, reveal themselves to be deeply inscribed in the cultural substratum of the peoples from which their authors originate. When this substratum is blended with the traditional novel, it enriches as well as reconfigures it, eventually giving rise to hybrid genres that are not simply recreations of the novel genre, but rigorous instruments for illustrating and defending ideological and artistic cultures confronted with the reality of aberrant post-colonial policies in Africa.Keywords: Novel, Writing, Historical consciousness, Liberation struggles, Postcolonial. La présente thèse analyse les mobiles d'inscription de la guerre indépendantiste du Cameroun dans les œuvres de quelques écrivains camerounais. Elle montre comment à travers les écritures romanesques, des écrivains camerounais nés à diverses époques de l'Histoire du Cameroun et évoluant dans divers contextes soulèvent des questions politiques et culturelles contemporaines. L'ouverture progressive des archives coloniales et militaires françaises, l'apparente volonté des politiques camerounaises et françaises d'ouvrir le débat sur les responsabilités des massacres de la guerre de libération du Cameroun et surtout les progrès dans le champ de la recherche sur cette période de l'histoire du Cameroun ont donné naissance à une littérature africaine francophone qui réinvestit le champ de l'Histoire pour raconter un moment critique de la marche politique de ce pays de l'Afrique centrale. On voit, en s'appuyant sur l'approche de la construction d'identités nationales par la mémoire, théorisée par Halbwachs, qu'en investissant le domaine de l'Histoire et de la mémoire, ces romans mobilisent un certain nombre de stratégies artistiques qui en effet, se révèlent être profondément inscrites dans le substrat culturel des peuples d'où sont originaires leurs auteurs. Lorsque ce substrat est mêlé au roman traditionnel, il l'enrichit autant qu'il le reconfigure et finit par donner naissance à des genres hybrides qui ne sont pas que de simple recréations du genre romanesque mais, des instruments rigoureux d'illustration et de défense de cultures idéologiques et artistiques confrontées à la réalité de politiques postcoloniales aberrantes en Afrique.Mots clés : Roman, Ecriture, Conscience historique, Luttes de libération, Postcolonial

Les messages du 31 décembre à la nation au Cameroun : lecture dispositive d’une communication présidentielle

Résumé : Cet article s’intéresse aux messages de fin / début d’année du Président de la République au Cameroun. La question à laquelle il répond est de savoir comment les messages du 31 décembre contribuent à structurer le dispositif de communication du discours politique dans un contexte où la légitimité du chef de l’État est continuellement contestée. Le corpus examiné est constitué d’une sélection de messages de début de décennie sur une quarantaine d’années d’exercice du pouvoir. L’analyse établit, dans un processus particulier de communication, le lien entre le discours, son environnement social et la stratégie politique du Président. La réflexion débouche sur un dispositif communicationnel des « messages du 31 décembre » construit autour de trois principales variables : les instances de communication en jeu, les enjeux de contrôle de l’opinion et les logiques discursives correspondantes.  Mots-clés : Message du 31 décembre, Communication présidentielle, Dispositif de communication, Cameroun