Pierre Marie Mapongmetsem

Toxicity of some terpenoids of essential oils of Xylopia aethiopica from Cameroon against Sitophilus zeamais Motschulsky

Abstract:  The acute toxicity of essential oils from the whole fruit (EF) or from the fibres of the fruit (FF) of the local aromatic plants Xylopia aethiopica Dunal (Annonaceae) collected in north Cameroon was evaluated on Sitophilus zeamais adults. A concentration of 1 ml of essential oil per 100 g of maize seeds was tested to determine weevil mortality after 24 h of exposure. Under these conditions, the essential oil derived from both EF and FF of X. aethiopica led to 100% mortality. In a second step, proportions of active compounds present in the oil of both EF and FF of X. aethiopica were quantified. The toxicity of the four main compounds was tested against S. zeamais: α‐pinene, β‐pinene, Δ‐3‐carene and terpinen‐4‐ol according to their proportion in the essential oil of the concerned plant part. β‐pinene and terpinen‐4‐ol were responsible for 50% of the mortality at the proportion found in EF and FF essential oils respectively. When mixed, a synergic effect of the compounds was observed that restored the mortality percentage observed for the crude oil. It appears that X. aethiopica essential oil could be a potential source of natural and low‐cost insecticide to control storage pests.

Woody species composition, structure and diversity of vegetation of Kalfou Forest Reserve, Cameroon

Studies were carried out in the Kalfou Forest Reserve to make an assessment of the flora diversity and to develop preservation guidelines facing the increase in its degradation. The composition of woody species, structure, diversity, density, dominance, frequency of species and family importance value were described and evaluated in all the forest reserve area. A total of 86 species representing 58 genera and 28 families of woody species were identified. The families of Combretaceae, Fabaceaecaesalpinioideae and Fabaceae-mimosoideae were the most abundant families in the Kalfou Forest Reserve. The density of stems ≥ 10 cm circumference and the basal area were higher in the Doulouk and Gonoray parts of the reserve. The distribution of stems of the main species in classes of circumference had shown a reverse “J” shaped curve. The number of stems of shrubs species was important and strongly influenced globally the diameter and the height of the stems which were lower. Species diversity was a slight difference among the various parts of the forest reserve area. The species abundance showed that, 20% of the species were infrequent. The dynamic of renewal of species were ensured by the weakly regeneration: seedling (2.03%), rejection issues (41.97%) and the death rate of individual species was 8.02%. Disturbances and the vulnerability of the seedlings did not ensure species sustainability. Preservation systems and adequate management were therefore recommended in order to ensure sustainable management of the Kalfou Forest Reserve resources.

Impact des systémes d’utilisation des terres sur la conservation de Vitellaria paradoxa Gaerten. F. (Sapotaceae) dans la région des savanes soudano-guinéennes

Vitellaria paradoxa (Butyrospermum parkii (G. Don) Kotschy) est l’une des essences locales d’intérêt socio-économique les plus valorisées par les populations locales dans les savanes soudano-guinéennes d’Afrique. Pendant que le volume des travaux s’accroît en Afrique de l’Ouest sur divers aspects scientifiques de cette Sapotaceae, peu de recherches lui sont consacrées au Cameroun. Afin de contribuer au développement des stratégies de sa conservation, une étude portant sur la structure de sa population et l’exploitation de cette ressource a été conduite dans le plateau de Ngaoundéré au Cameroun. Deux approches méthodologiques faisant intervenir des inventaires botaniques et des enquêtes ethnobotaniques ont été utilisées. Un total de 1966 arbres ont été recensés soit une densité moyenne de 16 individus ha-1. La répartition des arbres suivant les modes d’utilisation des terres montre que la savane naturelle regorge 79,5% de tiges. L’analyse de la structure de population de V. paradoxa révèle que la régénération de l’espèce est bonne tandis que sa survie est compromise par diverses pressions biotiques. La régénération par graines et par rejets de souche est largement influencée par les feux de brousse et le surpâturage. La pression anthropique la plus redoutable est la coupe des arbres pour une utilisation sous forme de bois – énergie. Toutefois, l’arbre coupé peut se maintenir par le rejet de souche. Ces informations vont contribuer à l’élaboration des stratégies appropriées de gestion et de conservation de l’espèce en vue de son introduction systématique dans les systèmes de production paysans. Mots clés : Conservation ; Mode de gestion des terres ; Régénération ; Structure de population ; V. paradoxa Vitellaria paradoxa (Butyrospermum parkii (G. Don) Kotschy) is a most important native tree valued by the local populations in the Sudan-Guinea savannah of Africa. In West Africa, the volume of scientific researches is increasing on this Sapotaceae, but there are few such studies in Cameroon. In order to develop appropriate conservation strategies, a study was undertaken on the population structure and management of the species, in the Ngaoundere highlands of Cameroon. Two methodological approaches using botanical and ethnobotanical surveys were used. A total of 1966 trees were recorded for a density of 16 stems ha-1. Distribution of trees according to the land use systems shows that natural savannah contains 79.5% of stems. The analysis of the population structure of V. paradoxa reveals that the regeneration of the species is good whereas the survival of the adult trees is compromised by various biotic pressures. Propagation by seed and sprouting is largely influenced by bush fires and overgrazing. The most important man-made pressure is fuel wood harvesting. Nevertheless, the species can re-sprout when cut. This information will help in elaborating suitable conservation and management strategies for the species in view of its systematic introduction in the farmer production systems.

Medicinal Plants Used for Treating Reproductive Health Care Problems in Cameroon, Central Africa1

Medicinal Plants Used for Treating Reproductive Health Care Problems in Cameroon, Central Africa. Approximately 80% of the African population uses traditional plants to deal with health problems, basically because of their easy accessibility and affordability. This study was carried out to document indigenous knowledge of medicinal plants used by traditional healers and elders in the treatment of reproductive health care in the Bamboutos Division of the West Region in Cameroon, Central Africa. The research methods used included semi–structured interviews and participative field observations. For the interviews, 70 knowledgeable respondents (40 traditional healers and 30 elders) were selected via purposive sampling. Voucher specimens were collected with the help of respondents, processed into the Cameroon National Herbarium in Yaoundé following standard methods, identified with the help of pertinent floras and taxonomic experts, and submitted to Department of Botany at the University of Dschang. Descriptive statistics were used to analyze and summarize ethnobotanical information obtained. Informant consensus factors (ICF) were used to elucidate the agreement among informants on the species to be used in the treatment within a category of illness. The results showed that a total of 70 plant species from 37 families (mostly of the Asteraceae [8 species], Euphorbiaceae [7], and Acanthaceae and Bignoniaceae [4 each]) are used in the treatment of 27 reproductive ailments, with the highest number of species (37) being used against venereal diseases, followed by female (29) and male infertility (21), respectively. Leaves (47.3%) were the most commonly harvested plant parts and the most common growth forms harvested were the herbs (45.7%), followed by shrubs (30%). Sixty percent of plant material was obtained from the wild ecosystems. Herbal remedies were mostly prepared in the form of decoction (66.2%) and were taken mainly orally. Informant consensus about usages of medicinal plants ranged from 0.5 to 1.0 with an average value of 0.91. It can be concluded that medicinal plants have played and will continue to play major roles in the management of reproductive healthcare in the study area.Plantes médicinales utilisées dans le traitement des affections des organes reproducteurs au Cameroun, Afrique Centrale. Approximativement, 80% de la population africaine utilisent les plantes pour résoudre leurs problèmes de santé. Cette large utilisation des plantes est attribuée à l’accessibilité et à leurs faibles coûts. Afin de contribuer à la documentation de ce riche héritage, une enquête ethnopharmacologique a été réalisée dans diverses localités du Département des Bamboutos, Ouest Cameroun, au sujet des plantes utilisées contre les affections des organes reproducteurs.Un total de 70 informateurs (40 guérisseurs et 30 personnes âgées)ont été consultés. A l’issu de l’enquête, 70 espèces de plantes appartenant à 64 genres et 37 familles botaniques avec une prédominance des familles des Asteraceae (8 espèces), des Euphorbiaceae (7), et des Acanthaceae et Bignoniaceae (4 espèces chacune) ont été répertoriées. Ces plantes sont employées pour traiter 27 affections des organes reproducteurs, avec en premier rang les maladies vénériennes qui utilisent 37 espèces, suivi de l’infertilité chez les femmes et les hommes, 29 et 21 espèces respectivement.La majorité (60%) de ces plantes est récoltée dans des jachères ou îlots forestières. Les types morphologiques les plus utilisés sont des herbes (45,7%), suivi des arbustes (30%). Les feuilles (47,3%) constituent la partie la plus utilisée, suivi des écorces (22,3%), plantes entières (19,7%), des tiges (5,2%), des tubercules (2,6%) et des inflorescences et fruits (1,3% chacun). La majorité de remèdes est préparée sous forme de décoction (66,2%) et sont majoritairement employées par voie orale, particulièrement en boisson. Les valeurs de consensus vis–à–vis des usages des différentes plantes sont comprises entre 0,5–1 avec une valeur moyenne de 0,91.Les plantes demeurent la seule source de médicament bio–disponible dans la zone d’étude et se verifie d’une part par l’usage accrue des herbes. Toutefois, elles peuvent servir de matière première pour la fabrication des médicaments modernes.

Analysis By Gc/Fid And Gc/Ms Of Essential Oil Of Leaflets Of Steganotaenia Araliacea Hochst From Cameroon

Abstract The essential oil from the leafets of Steganotaenia araliacea Hochst from the Adamaoua region of North Cameroon was analyzed by GC(FID) and GC/MS. More than 20 compounds have been identifed. Monoterpenes (60.3%) are mainly represented by limonene (31.9%) and α-pinene (17.8%); the main sesquiterpenes were γ-elemene (9.6%) and ar-curcumene (6.6%).

Socioeconomic Importance of the Banana Tree (Musa Spp.) in the Guinean Highland Savannah Agroforests

Home gardens are defined as less complex agroforests which look like and function as natural forest ecosystems but are integrated into agricultural management systems located around houses. Investigations were carried out in 187 households. The aim of the study was to identify the different types of banana home gardens existing in the periurban zone of Ngaoundere town. The results showed that the majority of home gardens in the area were very young (less than 15 years old) and very small in size (less than 1 ha). Eleven types of home gardens were found in the periurban area of Ngaoundere town. The different home garden types showed important variations in all their structural characteristics. Two local species of banana are cultivated in the systems, Musa sinensis and Musa paradisiaca. The total banana production is 3.57 tons per year. The total quantity of banana consumed in the periurban zone was 3.54 tons (93.5%) whereas 1.01 tons were sold in local or urban markets. The main banana producers belonged to home gardens 2, 4, 7, and 9. The quantity of banana offered to relatives was more than what the farmers received from others. Farmers, rely on agroforests because the flow of their products helps them consolidate friendship and conserve biodiversity at the same time.

Boswellia dalzielii Hutch : état du peuplement et utilisation traditionnelle dans la région de Mbé (Adamaoua-Cameroun)

L’interet sans cesse grandissant porte aux produits forestiers non ligneux (PFNL) au Cameroun a suscite une etude dans la region de Mbe sur la gestion des peuplements de Boswellia dalzielii, une plante medicinale a grande valeur spirituelle. Les observations de terrain montrent que les populations prelevent les ecorces en plaques de forme rectangulaire. La hauteur minimale de collecte des PFNL (1,30 m) n’est pas respectee, mais le volume maximal d’ecorces prelevees (40 482 cm 3) n’est pas susceptible de mettre la ressource en peril. L’absence de jeunes et vieux individus dans le milieu montre que la regeneration et le maintien de cette espece sont problematiques. Des etudes sur la sylviculture de cette espece sont necessaires pour satisfaire les besoins des populations locales car la vulgarisation des connaissances sur l’espece peut l’exposer a une exploitation a grande echelle.

Distribution des combretums en rapport avec l’aridité au Cameroun

Dans la perspective de recherche des indicateurs biologiques susceptibles d’interpréter les changements des conditions d’un milieu, une étude, sur la distribution des combretums, a été effectuée dans les provinces administratives de l’Est, Adamaoua et extrême nord du Cameroun; suivant le gradient d’aridité croissant. A l’issus des prospections de terrain, il ressort que la diversité des combretums le long du gradient climatique Est–extrême nord est très perceptible. D’une manière générale, la densité de ces espèces croit au fur et à mesure que l’on va des régions humides aux régions plus sèches. Toutefois, une étude plus fine se doit d’être menée pour confirmer les résultats de ce travail. Mots clés: Combretum; Distribution; Aridité; Cameroun In order to determine the biological indicator which can permit understanding of environmental changes, a study was carried out on combretum distribution in the administrative provinces of East, Adamawa and Extreme‐North, in Cameroon, along a gradient of increasing aridity. After field exploration, it appears that there is combretum diversity along the East–Extreme north climatic gradient. In general, the species density increases also from the humid to the driest zone. There is a need for further research to confirm this trend.

The colonizing flora ofCanarium schweinfurthii in the grassfields of Cameroon

Agroforestry affords diversification and intensification of farming systems through the integration of indigenous trees such as canarium (Canarium schweinfurthii [Burseraceae]) which produce marketable products. Although biodiversity in agrosystems is one of the cornerstones of sustainability, little is known about the colonizing organisms of the species introduced. A study was carried out in six Divisions of the grassfields of Cameroon in order to identify the most common epiphytes and parasites of the canarium tree. Sixteen species of vascular epiphytes were recorded, of which 93.75% were holoepiphytes and 6.25% hemiepiphytes. Of the different families encountered. Orchidaceae represented 62.50%, Polypodiaceae 25%, and Davalliaceae and Cactaceae each only 6.25%. In the grassfields of Cameroon, the distribution patterns of vascular epiphytes vary in two ways. Horizontally, there is a significant difference between divisions (P<0.001).Microsorium punctatum andRhipsalis baccifera were specific to Menoua Division andMicrocoelia macrorrhynchia to Mezam Division. Vertically, there is also significant variation from the tree base to the canopy (P<0.001), the lower and middle canopy being the preferred positions. Four species of parasites were recorded:Ficus thonningii, Ficus vallis-choudae (Moraceae),Hymenodyction floribundum (Rubiaceae) andTapinanthus loranthus (Loranthaceae). The Moraceae and Rubiaceae prefer the basal and lower trunk, whereas the Loranthaceae prefer the lower and upper canopy of the tree. The parasites, in contrast to the epiphytes, lead to the death of the canarium tree.