Chemical composition of Cinnamosma madagascariensis (Cannelaceae) essential oil and its larvicidal potential against the filariasis vector Culex quinquefasciatus Say

Madagascar flora is diverse and unique. Cinnamosma madagascariensis is an endemic species widely present in the forests of Madagascar. This plant has important traditional uses ranging from management of dementia, epilepsy, headache to malaria. Fewdata have been reported about the chemical composition of the essential oil, and no studies have been published on its bioactivity againstmosquitoes. Here,we focus on the chemical composition of essential oils extracted from C. madagascariensis stem bark and leaves, and their larvicidal potential against the filariasis vector Culex quinquefasciatus. GC-MS analysis revealed differences between the chemical volatile profiles of leaves and bark oils. In the former, linalool (30.1%), limonene (12.0%), myrcene (8.9%) and α-pinene (8.4%) were the major constituents, while in the latter β-pinene (33.3%), α-pinene (19.3%) and limonene (12.0%) were the most representative compounds. Acute toxicity experiments conducted on larvae of the filariasis vector C. quinquefasciatus led to LC50 of 61.6 μL L−1 and 80.1 μL L−1 for the bark and the leaf essential oils, respectively. Overall, the chance to use compounds from the C. madagascariensis bark and leaf essential oils against filariasis vectors seems promising, since they are effective at moderate doses and could be an advantageous alternative to build newer and safer mosquito control tools. To the best of our knowledge, this is the first report about the chemical composition of C. madagascariensis essential oils

Étude de la cristallisation d'une cire paraffinique dans nn-tetradecane. Comparaison avec le nn-pentacosane

L'étude de la solubilité d'une cire paraffinique, dite de type “normale”; issue de déparaffinage des huiles lubrifiantes et celle d'un n-alcane pur dont le nombre de carbones est égal au nombre de carbones moyen de la cire, dans un solvant est réalisée par analyse thermique simple et différentielle. Les résultats obtenus montrent, d'une part, que les deux systèmes (Cire, C$_{14}$) et (C$_{25}$, C$_{14}$) ont des diagrammes de phases superposables dans tout le domaine de composition et d'autre part, les deux diagrammes présentent une solidification eutectique binaire. Ce qui nous a donc amener à considérer la cire comme un pseudo constituant pur ou “composé définit”. La prédiction de température de cristallisation commençante du système (C$_{25}$, C$_{14}$) est réalisée à l'aide du modèle de Flory Huggins

The Vepris macrophylla essential oil produces notable antiproliferative activity and morphological alterations in human breast adenocarcinoma cells

Medicinal plants contain numerous bioactive molecules that synergistically provide therapeutic benefits. We have devoted our attention to various EOs without toxicity to normal cells, studying their activities against human cancer cells. In particular, we have studied the cytotoxicity of Vepris macrophylla (Baker) I. Verd. EO. V. macrophylla is an evergreen tree of Madagascar where is much appreciated as a source of traditional remedies. Its major volatile components are citral, i.e., a mixture of neral and geranial, citronellol and myrcene. The antiproliferative activities of V. macrophylla EO were studied against human breast adenocarcinoma cell line SKBR3. Cellular metabolism was analyzed by MTT assay at different concentrations of EO and at different times of incubation (24, 48 and 72 h). Moreover, morphological and ultrastructural analyses were performed to study its antiproliferative effects against human adenocarcinoma cells, demonstrating the ability of V. macrophylla EO, stored inside numerous intracellular vesicles, to damage both plasma membranes and disorganize the cytoskeleton protein as actin filaments

Chemical composition and insecticidal activity of the essential oil from Helichrysum faradifani endemic to Madagascar

Helichrysum faradifani (Asteraceae) is a perennial shrub growing in rocky and sandy places of Madagascar. The plant is used in the Malagasy traditional medicine as wound healing and disinfectant and for the treatment of syphilis, diarrhoea, cough and headache. In the present work, we analyzed the chemical composition of the essential oil distilled from the aerial parts of H. faradifani by GC-MS and evaluated its insecticidal activity against 2nd, 3rd and 4th instar larvae of the lymphatic filariasis vector Culex quinquefasciatus by acute toxicity assays. The most sensitive were 2nd instar (LC50=85.7 μl.L-1) larvae. For the 3rd and 4th instar larvae the estimated LC50 were 156.8 and 134.1 μl.L-1, respectively. Monoterpene hydrocarbons (51.6%) were the major fraction of the essential oil, with the bicyclic -fenchene (35.6%) as the predominant component. Sesquiterpene hydrocarbons (34.0%) were the second major group characterizing the oil, with -curcumene (17.7%) as the most abundant component

Insecticidal and mosquito repellent efficacy of the essential oils from stem bark and wood of Hazomalania voyronii

Ethnopharmacological relevance: The use of Hazomalania voyronii, popularly known as hazomalana, to repel mosquitoes and resist against insect attacks is handed down from generation to generation in Madagascar. In the present study, we investigated the ability of the essential oils (EOs) obtained from the stem wood, fresh and dry bark of H. voyronii to keep important mosquito vectors (Aedes aegypti and Culex quinquefasciatus) away, as well as their toxicity on three insect species of agricultural and public health importance (Cx. quinquefasciatus, Musca domestica and Spodoptera littoralis). Materials and methods: Hydrodistillation was used to obtain EOs from stem wood, fresh and dry bark. The chemical compositions were achieved by gas chromatography-mass spectrometry (GC-MS). Toxicity assays using stem wood and bark EOs were performed on larvae of Cx. quinquefasciatus and S. littoralis, and adults of M. domestica by WHO and topical application methods, respectively. Mosquito repellent activity of the most effective EO, i.e. the bark one, was determined on human volunteers by arm-in-cage tests, and results were compared with that of the commercial repellent N,N-ddiethyl-m-toluamide (DEET). Results: The H. voyronii EOs were characterized by oxygenated monoterpenes with perilla aldehyde (30.9–47.9%) and 1,8-cineole (19.7–33.2%) as the main constituents. The fresh and dry bark EOs were the most active on Cx. quinquefasciatus and S. littoralis larvae, respectively, with LC50/LD50 of 65.5 mg L−1, and 50.5 μg larva−1; the EOs from wood and fresh bark displayed the highest toxicity on M. domestica (LD50 values 60.8 and 65.8 μg adult−1, respectively). Repellence assay revealed an almost complete protection (>80%) from both mosquito species for 30 min when pure fresh bark EO was applied on the volunteers’ arm, while DEET 10% repelled >80% of the mosquitoes up to 120 min from application. Conclusion: The traditional use of the bark EO to repel insects has been demonstrated although an extended-release formulation based on H. voyronii EOs is needed to increase the repellent effect over time. A wide spectrum of insecticidal activity has been provided as well, suggesting a possible use of H. voyronii EOs in the fabrication of green repellents and insecticides useful to control mosquito vectors and agricultural pests

Vepris macrophylla (Baker) I. Verd essential oil: an antifungal and possible inhibitor of mycotoxins production

Rutaceae are widely used in ethnomedicine to treat infectious diseases in humans and plants. In this study, the antifungal activity of the Vepris macrophylla leaf essential oil (VEO) and its main components, citral and citronellol, was evaluated against six phytopathogenic fungi. In addition, the possible action of VEO on the synthesis of mycotoxins was evaluated as well. To determine the antifungal activity of VEO we used the agar dilution method and VEO showed inhibitory activity against all the tested fungi. In particular, VEO resulted to be fungicidal against Phytophthora cryptogea and Fusarium avenaceum. For all other fungi VEO exhibited fungistatic activity and the weakest effect was observed on Alternaria solani. Citral was very effective against P. cryptogea, F. avenaceum, F. poae and F. graminearum. On the other hand, citronellol showed good activity towards P. cryptogea and F. avenaceum and weaker activity towards F. poae and F. graminearum. It can be concluded that VEO can be considered a promising antifungal agent, especially against P. cryptogea and F. avenaceum, suggesting a possible use in the formulation of new selective and natural fungicides