Effet Bio-Insecticide De L’huile Essentielle Et De La Poudre De Chenopodium Ambrosioides L. Sur Les Imagos De Bruches De Haricots En Stockage

Le but de l’étude est d’évaluer l’effet d’insecticide et d’insectifuge de l’huile essentielle et de la poudre de Chenopodium ambrosioides L. contre Acanthoscelides obtectus Say, bruches de haricots. Après séchage de la partie terminale de C. ambrosioides, une aliquote de la matière sèche a été utilisée pour extraire par hydro-distillation de l’huile essentielle et une autre partie broyée pour produire une poudre fine après tamisage. L’analyse de l’huile extraite a été réalisée par chromatographie en phase gazeuse à ionisation de flamme couplée à la spectrométrie de masse. La toxicité de cette huile contre les bruches a été évaluée par fumigation avec ou sans graines, répulsion, contact sur papier filtre avec graines et contact avec graines. Il a été prouvé la toxicité de la poudre vis à vis des bruches de haricots. Le taux de répulsion (%) ou la mortalité des bruches a été déterminée par test. La DL50 a été calculée après que les bruches A. obtectus ont été exposées à l’huile essentielle et à la poudre à la moitié de la durée totale de l’expérience. L’huile essentielle extraite est composée d’hydrocarbures monoterpéniques (52,14 %) avec 37,15 % de α-terpinène et 13,55 % de p-cymène. Elle est riche en monoterpènes oxygénés (6,26 %) dont l’isoascaridole représente 5,43 %. La DL50 de l’huile essentielle est de 0,0017 μl/cm3, 0,017 μl/cm2, 0,0127 μl/g, 0,0032 μl/g respectivement pour le test de fumigation sans graines, de contact avec papier filtre, de fumigation avec graines et de contact avec graines. Avec la poudre, DL50 est de 19,5 g/kg. L’huile a montré un effet attractif pour le test de répulsion. Cette huile et la poudre ont influencé le cycle de développement des bruches en réduisant leur nombre des imagos émergées en F1. Cette huile a été plus efficace que la poudre. Le test in planta confirmera l’efficacité de l’huile essentielle extraite de C. ambrosioides contre les bruches A. obtectus. The aim of this study is to evaluate the insecticide and insectifuge effect of Chenopodium ambrosioides L. essential oil and powder against Acanthoscelides obtectus Say which are beans’ weevil. After drying the terminal part of C. ambrosioides, a certain quantity of dried latter was used for extraction by hydro-distillation of essential oil and the other part was grounded to produce a thin powder sifting. Analysis of the extracted oil was done by chromatography in gaseous phase at flame ionization coupled with mass spectrometry. Toxicity of the oil on weevil was evaluated by fumigation with or without seeds, repulsion, contact on filter paper with seeds and contact with seeds. It was proven the toxicity of the powder face to beans’ weevil. Repulsion rate (%) or mortality of the weevils was determined by test. DL50 was calculated after weevil A. obtectus have been exposed to essential oil and powder at half time of the total duration of the experimentation. The extracted essential oil is composed of monoterpenic hydrocarbons (52.14 %) with 37.15 % of α-terpinen and 13.55 % of p-cymene. The oil is rich in oxygenated monoterpenes (6.26 %) of which the isoascaridol represents 5.43 %. The DL50 of the essential oil equals 0.0017 μl/cm3, 0.017 μl/cm2, 0.0127 μl/g, 0.0032 μl/g for the fumigation without seeds test, the contact with filter paper, fumigation with seeds and contact with seeds respectively. With the powder, the DL50 equals 19.5 g/kg. The oil showed an attractive effect for the test of repulsion. That oil and the powder influenced the development cycle of the weevils by reducing the number of images emerged in F1. That oil was more efficient than the powder. The test in planta will confirm the efficiency of the extracted essential oil from C. ambrosioides against the weevils A. obtectus

Clausena anisata and Dysphania ambrosioides essential oils: from ethno-medicine to modern uses as effective insecticides

Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) and Clausena anisata (Willd.) Hook. f. ex Benth. (Rutaceae) are two aromatic species traditionally used in Cameroon to repel and kill insects. The present work was carried out to substantiate this traditional use and to evaluate the possible incorporation in commercial botanical insecticides of their essential oils (EOs). The EOs were distilled from leaves of C. anisata and aerial parts of D. ambrosioides and analyzed by gas chromatography-mass spectrometry (GC-MS). The insecticidal activity of both EOs was investigated against the filariasis vector, Culex quinquefasciatus and the housefly, Musca domestica. As possible mode of action, the inhibition of acetylcholinesterase (AChE) by the two EOs was investigated as well. The D. ambrosioides EO was characterized by the monoterpene peroxide ascaridole (61.4%) and the aromatic p-cymene (29.0%), whereas the C. anisata EO was dominated by the phenylpropanoids (E)-anethole (64.6%) and (E)-methyl isoeugenol (16.1%). The C. anisata EO proved to be very toxic to 3rd instar larvae of C. quinquefasciatus showing LC50 of 29.3 l/l, whereas D. ambrosioides EO was more toxic to adults of M. domestica showing a LD50 of 51.7g/adult. The mixture of both EOs showed a significant synergistic effect against mosquito larvae with LC50 estimated as 19.3 l/l, whereas this phenomenon was not observed upon application to M. domestica adults (LD50 = 75.9g/adult). Of the two EOs, the D. ambrosioides one provided a good inhibition of AChE (IC50 = 77 g/ml), whereas C. anisata oil was not effective. These findings provide new evidences supporting the ethnobotanical use of these two Cameroonian plants, and their possible application even in synergistic binary blends, to develop new eco-friendly, safe and effective herbal insecticides

Trypanosoma brucei Inhibition by Essential Oils from Medicinal and Aromatic Plants Traditionally Used in Cameroon (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea and Echinops giganteus)

Essential oils are complex mixtures of volatile components produced by the plant secondary metabolism and consist mainly of monoterpenes and sesquiterpenes and, to a minor extent, of aromatic and aliphatic compounds. They are exploited in several fields such as perfumery, food, pharmaceutics, and cosmetics. Essential oils have long-standing uses in the treatment of infectious diseases and parasitosis in humans and animals. In this regard, their therapeutic potential against human African trypanosomiasis (HAT) has not been fully explored. In the present work, we have selected six medicinal and aromatic plants (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea, and Echinops giganteus) traditionally used in Cameroon to treat several disorders, including infections and parasitic diseases, and evaluated the activity of their essential oils against Trypanosma brucei TC221. Their selectivity was also determined with Balb/3T3 (mouse embryonic fibroblast cell line) cells as a reference. The results showed that the essential oils from A. indica, A. daniellii, and E. giganteus were the most active ones, with half maximal inhibitory concentration (IC50) values of 15.21, 7.65, and 10.50 mu g/mL, respectively. These essential oils were characterized by different chemical compounds such as sesquiterpene hydrocarbons, monoterpene hydrocarbons, and oxygenated sesquiterpenes. Some of their main components were assayed as well on T. brucei TC221, and their effects were linked to those of essential oils