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Bertani, S., Houel, E., Stien, D., Chevolot, L., Jullian, V., Garavito, G., et al. (2006). Simalikalactone D is responsible for the antimalarial properties of an amazonian traditional remedy made with Quassia amara L. (Simaroubaceae). J. Ethnopharmacol., 108(1), 155–157.
Abstract: French Guiana (North-East Amazonia) records high malaria incidence rates. The traditional antimalarial remedy most widespread there is a simple tea made out from Quassia amara L. leaves (Simaroubaceae). This herbal tea displays an excellent antimalarial activity both in vitro and in vivo. A known quassinoid, simalikalactone D (SkD), was identified as the active compound, with an IC50 value of 10 nM against FeB1 Plasmodium falciparum chloroquine resistant strain in vitro. Lastly, it inhibits 50% of Plasmodium yoelii yoelii rodent malaria parasite at 3.7 mg/kg/day in vivo by oral route. These findings confirm the traditional use of this herbal tea. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
Keywords: antimalarial; Quassia amara; quassinoids; simalikalactone D; traditional medicine
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Boulogne, I., Constantino, R., Amusant, N., Falkowski, M., Rodrigues, A. M. S., & Houel, E. (2017). Ecology of termites from the genus Nasutitermes (Termitidae: Nasutitermitinae) and potential for science-based development of sustainable pest management programs. Journal of Pest Science, 90(1), 19–37.
Abstract: The genus Nasutitermes is among the most abundant wood-feeding Termitidae and an extremely diverse and heterogeneous group in terms of its biogeography and morphology. Despite the major role of several Nasutitermes species as structural pests, the phylogenetic status of this genus is still unclear, along with a confused taxonomy and species identification remaining difficult. The first aim of this review was thus to gather and discuss studies concerning the taxonomic status of the genus Nasutitermes in order to clarify this crucial point. Then, our goal was to gain new insights into the management of N. corniger, considered to be the most economically detrimental pest of this genus in South America and a Nasutitermes model species, while filtering available information concerning its biology through the prism of termite control, as well as critically examine the existing methods. We indeed strongly believe that increasing our knowledge of this species’ biological strategies is the key to progress in the challenging question of their sustainable management. © 2016, Springer-Verlag Berlin Heidelberg.
Keywords: Antimicrobial and insecticidal botanical extracts; Ipm; Nasutitermes corniger; Sustainable management; Taxonomic history; Termitidae
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Fu, T., Touboul, D., Della-Negra, S., Houel, E., Amusant, N., Duplais, C., et al. (2018). Tandem Mass Spectrometry Imaging and in Situ Characterization of Bioactive Wood Metabolites in Amazonian Tree Species Sextonia rubra. Anal. Chem., 90(12), 7535–7543.
Abstract: Driven by a necessity for confident molecular identification at high spatial resolution, a new time-of-flight secondary ion mass spectrometry (TOF-SIMS) tandem mass spectrometry (tandem MS) imaging instrument has been recently developed. In this paper, the superior MS/MS spectrometry and imaging capability of this new tool is shown for natural product study. For the first time, via in situ analysis of the bioactive metabolites rubrynolide and rubrenolide in Amazonian tree species Sextonia rubra (Lauraceae), we were able both to analyze and to image by tandem MS the molecular products of natural biosynthesis. Despite the low abundance of the metabolites in the wood sample(s), efficient MS/MS analysis of these γ-lactone compounds was achieved, providing high confidence in the identification and localization. In addition, tandem MS imaging minimized the mass interferences and revealed specific localization of these metabolites primarily in the ray parenchyma cells but also in certain oil cells and, further, revealed the presence of previously unidentified γ-lactone, paving the way for future studies in biosynthesis.
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Courtois, E. A., Baraloto, C., Timothy Paine, C. E., Petronelli, P., Blandinieres, P. - A., Stien, D., et al. (2012). Differences in volatile terpene composition between the bark and leaves of tropical tree species. Phytochemistry, 82, 81–88.
Abstract: Volatile terpenes are among the most diverse class of defensive compounds in plants, and they are implicated in both direct and indirect defense against herbivores. In terpenes, both the quantity and the diversity of compounds appear to increase the efficiency of defense as a diverse blend of compounds provides a more efficient protection against a broader range of herbivores and limits the chances that an enemy evolves resistance. Theory predicts that plant defensive compounds should be allocated differentially among tissues according to the value of the tissue, its cost of construction and the herbivore pressure on it. We collected volatile terpenes from bark and leaves of 178 individual tree belonging to 55 angiosperm species in French Guiana and compare the kind, amount, and diversity of compounds in these tissues. We hypothesized that in woody plants, the outermost part of the trunk should hold a more diverse blend of volatile terpenes. Additionally, as herbivore communities associated with the leaves is different to the one associated with the bark, we also hypothesized that terpene blends should be distinct in the bark vs. the leaves of a given species. We found that the mixture of volatile terpenes released by bark is different and more diverse than that released by leaves, both in monoterpenes and sesquiterpenes. This supports our hypothesis and further suggests that the emission of terpenes by the bark should be more important for trunk defense than previously thought.
Keywords: French Guiana; Herbivory; Optimal defense theory; Secondary metabolites; Wood
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Touré, S., Nirma, C., Falkowski, M., Dusfour, I., Boulogne, I., Jahn-Oyac, A., et al. (2017). Aedes aegypti Larvicidal Sesquiterpene Alkaloids from Maytenus oblongata. Journal of Natural Products, 80(2), 384–390.
Abstract: Four new sesquiterpene alkaloids (1-4) with a β-dihydroagrofuran skeleton and a new triterpenoid (5) were isolated from an ethyl acetate extract of Maytenus oblongata stems. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS and ECD experiments. The M. oblongata stem EtOAc extract and the pure compounds isolated were tested for larvicidal activity against Aedes aegypti under laboratory conditions, and compounds 2 and 3 were found to be active. © 2017 The American Chemical Society and American Society of Pharmacognosy.
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