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Nirma, C., Rodrigues, A., Basset, C., Stien, D., & Eparvier, V. (2010). Isoflavonoids with insecticide and larvicide activities from Muellera frutescens Standl. In Planta Medica (Vol. 76, pp. 1197–1198).
Abstract: Many plants of the Fabaceae family, are used as fish poisoning and insecticides [1,2]. The genus Muellera in this family is represented by only seven species of climbers and trees and is distributed over south and central America. In 1984, Geesink proposed to consider Muellera as Lonchocarpus synonymous [3]. The Lonchocarpus genera is well known in French Guiana because of its traditional utilization as a fish poisoning [4]. However, one study only reported ethnobotanical use of M. frutescens as an ichtyotoxic plant. Furthermore, no ethnopharmacological use or biological activity data was ever reported in the literature for this plant. Many chemical studies dealing with Lonchocarpus genera have been published [5,6,7]. Phytochemical investigation of barks, stems and rarely leaves described isolation of active isoflavonoids named rotenoids. This study aims at conducting a phytochemical survey of Muellera frutescens in order to evaluate whether or not Muellera is closely related to Lonchocarpus and eventually isolate new bioactive secondary metabolites. Three different extracts (hexane, ethyl acetate and methanol) of bark, roots and leaves were prepared and tested on various biological assays. We discovered insecticide and larvicide activities for all extracts, and none of them exhibited cytotoxicity on human cells. The bioguided fractionation of the most active extract (bark hexane extract) allowed us to isolate eight isoflavonoids, the structures of which were elucidated by spectroscopic methods. It was found that Muellera is indeed closely related to Lonchocarpus, therefore corroborating Geesink's proposal.
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Nicolle, S., & Leroy, M. (2013). Stratégies de partage et diffusion de données publiques environnementales : cas d’étude en Amazonie française et brésilienne. NetCom, 27(1-2), 60–87.
Abstract: Cet article se propose d’analyser les stratégies mises en œuvre en France et au Brésil vis-à-vis de la production et de la diffusion de données de suivi de pressions anthropiques sur les écosystèmes amazoniens, à savoir les impacts de l’orpaillage en Guyane française et du développement agricole au Brésil. On montre qu’indépendamment de la législation en vigueur, les stratégies mises en œuvre par les États sont très différentes et que cela influe de façon déterminante sur les positionnements et revendications de la société civile vis-à-vis de ces données. Au cours de la dernière décennie, le Brésil tend vers une ouverture croissante de l’accès aux données concernant la déforestation, poussé à la transparence par la contre-expertise d’ONG nationales et par la pression internationale. En Guyane, on constate au contraire un mouvement de fermeture des données concernant le suivi des impacts de l’orpaillage, lié à une implication croissante des services d’État en charge de la sécurité nationale dans le processus de suivi.
Keywords: Données libres; stratégie environnementale; Amazonie; Brésil; Guyane
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Nicolle, S. (2012). Sharing and distributing environmental data: study cases in a French and Brazilian Amazonian context. In Sharing environmental information;
issues of open environmental data in Latin America (pp. 1–5). Porto Alegre, Brésil.
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Nicolle, S. (2014). Les espaces naturels protégés en forêt amazonienne. Des doctrines de gestion aux dispositifs : quelle efficacité pour la proctection de l'environnement ? Ph.D. thesis, Université Antilles Guyane, Cayenne - Guyane française.
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Niamké, F., Kokutse, A. D., Kadio, A. A., Lemenager, N., Baudasse, C., Nourissier-Mountou, S., et al. (2012). Nirs Tools for Prediction of Main Extractives Compounds of Teak (Tectona grandis L.) Heartwood. In 2012 IUFRO Conference proceedings (Vol. Division 5 Forest products). Lisbonne, Portugal.
Abstract: Biochemical and physiological process which occurred during heartwood formation have consequences on wood properties such as colour, natural durability and some mechanical properties. However, it is very time-consuming to take measurements of extractives contents. Teak has been reported to contain 1-hydroxy-2-methyl-anthraquinone, 2-hydroxy-methyl-anthraquinone, 2-methyl-anthraquinone, lapachol, 1,4-naphthoquinone for the main compounds.
In teak, natural durability is ascribed to extractives. Consequently, it’s possible to estimate natural durability by measurement of extractives indirectly. For the purposes of selection for the production of improved varieties, the number of samples to be measured rapidly exceeds the capacity of a traditional laboratory.
Near-infrared spectroscopy approach, based on spectral data and reference data, is a tool enabling many of the chemical properties of wood to be predicted and the number of laboratory measurements to be reduced exponentially. The issue here is a question of checking the effectiveness of NIRS tool to build models and predict the main extractive compounds of teak wood from Ivory Coast. We try to calibrate these chemical properties with Nirs spectral information measured on grounded wood.
The results show the possible use of NIRS to predict total phenol content and some main extractive compounds of teak heartwood as tectoquinone, 2-hydroxymethylanthraquinone, … Consequently, after verification on other sets of teak samples, which may or may not be included in the prediction model, NIRS can be used to predict extractive compounds accurately for a large number of samples, making it possible to estimate natural durability indirectly and to include these characteristics in the selection criteria for classifying wood and high throughput phenotyping.
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Niamké, F., Amusant, N., Lemenager, N., Chaix, G., Thévenon, M. - F., Baudassé, C., et al. (2011). Decay resistance attributes of teak (Tectona grandis L. f.) wood: comparison of the fungicidal activities of quinones. In IRG/WP (Vol. 11). Queenstown, New Zealand.
Abstract: The implication of quinones in decay resistance of teak wood is controversial. To better understand the role of individual quinone in this property, we studied the correlations between this latter and the content of 2-(hydroxymethyl)anthraquinone, tectoquinone, anthraquinone-2-carboxylic acid, 1,4-naphthoquinone, lapachol and the new compound 4’,5’-dihydroxy-epiisocatalponol found in teak wood. Then, we studied the fungicidal activities of these quinones in comparison to acetone/water extracts from teak heartwood and sapwood and also with the commercial biocide tebuconazole. Broth dilution technique was used to assess the toxicity of these compounds against Trametes versicolor and Poria placenta. Decay resistance was measured according to current standards and individual quinones content were quantified by high performance liquid chromatography. High positive correlations were found between teak decay resistance and the content of 4’,5’-dihydroxy-epiisocatalponol, tectoquinone, 2-(hydroxymethyl)anthraquinone. Whereas no correlation was found with anthraquinone-2-carboxylic acid, lapachol and 1,4-naphthoquinone. Concerning the fungicidal activities of teak wood extractives, acetone/water heartwood extract was toxic against the two fungi while that of acetone/water sapwood was only fungistatic. 1,4-naphthoquinone and 4’,5’-dihydroxy-epiisocatalponol from the naphthoquinones family were fungicide. However, lapachol and all studied anthraquinones (2-(hydroxymethyl)anthraquinone, anthraquinone-2-carboxylic acid and tectoquinone) were fungistatic or not toxic. In the present study, 1,4-naphthoquinone was found the more toxic with a fungicidal activity 1000-times lower than that of the commercial biocide and over 2000-times lower than that of acetone/water heartwood extracts. These results show that decay resistance of teak wood could be mostly due to the content of naphthoquinone, particularly to that of 1,4-naphthoquinone indicating that it could be used as a potential wood preservative for lesser durable species.
Keywords: Tectona grandis; decay resistance; quinone; heartwood; brown and white rot fungi
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Niamké, B. F., & Amusant, N. (2014). Déterminants biochimiques de la durabilité naturelle du bois de teck Recherche des composés phénoliques impliqués dans la durabilité naturelle du teck. Edition Universitaire Européenne.
Abstract: La durabilité du bois est une propriété très importante pour son usage futur. Chez le teck, cette propriété peut varier selon le génotype et les facteurs environnementaux mais aussi en fonction de la composition chimique du bois. Le présent document s’est attaché à rechercher les déterminants biochimiques de la durabilité naturelle chez le teck. Il ressort de cette étude que les formes osidiques stockées dans l’aubier sont transformées en extractibles de nature quinonique. Ces mécanismes de transformation pourraient indiquer le niveau de durabilité naturelle des espèces. Ainsi, les corrélations établies entre la durabilité naturelle et les teneurs en composés phénoliques ont permis d’identifier et de caractériser quelques traits de cette propriété. En outre, l’activité fongicide de ces composés phénoliques a été déterminée afin de s’assurer de leur implication dans la propriété de résistance du bois de teck. Ces nouvelles données contribueront à l’amélioration de la qualité du bois qui par ailleurs assure la pérennité des arbres.
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Muller, F. (2008). Estimation de la vitesse de décomposition du bois mort en forêt tropicale humide : rôle des caractéristiques individuelles et spécifiques. Master's thesis, SupAgro, Montpellier - France.
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Morneau, F. (2002). Effet de la densité des arbres sur la régénération naturelle du Wacapou (Vouacapoua Americana Aublet, Caesalpiniaceae) en Guyane française. Master's thesis, Université Pierre et Marie Curie (ParisVI), Paris.
Keywords: Foret Tropicale Guyanaise Vouacapoua Americana Wacapou Nouragues Densite Des Arbres Adultes Regeneration Naturelle
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Morneau, F. (2007). Effets d'un gradient d'engorgement sur la structure et la dynamique d'une forêt tropicale humide (Paracou, Guyane française). Ph.D. thesis, Ecole Nationale du Génie Rural, des Eaux et des Forêts, Kourou.
Keywords: Distribution Des Especes; Dynamique Forestiere; Facteur Edaphiques; Niche; Heliophilie; Foret Tropicale Humide; Paracou
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