Maia, A. C. D., Gibernau, M., Dötterl, S., Do Amaral Ferraz Navarro, D. M., Seifert, K., Müller, T., et al. (2013). The floral scent of Taccarum ulei (Araceae): Attraction of scarab beetle pollinators to an unusual aliphatic acyloin. Phytochemistry, 93, 71–78.
Abstract: The strongly fragrant thermogenic inflorescences of Taccarum ulei (Araceae) are highly attractive to nightactive scarab beetles of Cyclocephala celata and C. cearae (Scarabaeidae, Cyclocephalini), which are effective pollinators of plants in the wild in northeastern Brazil. GC-MS analysis of headspace floral scent samples of T. ulei established that two constituents, (S)-2-hydroxy-5- methyl-3-hexanone (an aliphatic acyloin rarely detected in flowers) and dihydro-b-ionone (an irregular terpene) accounted for over 96% of the total scent discharge. Behavioral tests (in both field and cages) showed that male and female C. celata and C. cearae were attracted to traps baited with a synthetic mixture of both compounds; however, they were also responsive to (S)-2-hydroxy-5-methyl-3-hexanone alone, which thus functions as a specific attractive cue. These findings support other recent research in suggesting that angiosperms pollinated by cyclocephaline scarab beetles release floral odors of limited complexity in terms of numbers of compounds, but often dominated by unusual compounds that may ensure attraction of specific pollinator species. © 2013 Elsevier B.V.
Keywords: (S)-2-Hydroxy-5-methyl-3-hexanone; Araceae; Behavioral tests; Cyclocephala celata and C. cearae; Dihydro-β-ionone; Floral volatiles; Taccarum ulei
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Casella, T. M., Eparvier, V., Mandavid, H., Bendelac, A., Odonne, G., Dayan, L., et al. (2013). Antimicrobial and cytotoxic secondary metabolites from tropical leaf endophytes: Isolation of antibacterial agent pyrrocidine C from Lewia infectoria SNB-GTC2402. Phytochemistry, 96, 370–377.
Abstract: Because of the symbiotic nature of endophytes, this survey aims to investigate the probability of discovering antibacterial, antifungal and cytotoxic activities in leaf endophytic microbes. We isolated 138 cultivable microbes (121 fungi, 3 bacteria and 14 unidentified or unknown microbes) from 24 plant species, a significant relative proportion of which exhibited antifungal and cytotoxic potential against Candida albicans ATCC 10213 and the human cell lines KB (uterine cervical carcinoma), MDA-MB-435 (melanoma), and MRC5 (normal human lung fibroblasts). Three active fungal extracts were fractionated, resulting in the isolation of eight compounds. Seven had been described in the literature including the following: acremonisol A, semicochliodinol A, cochliodinol, griseofulvin, pyrenocin A, novae zelandin A and alterperylenol. A previously unreported compound named pyrrocidine C was isolated from Lewia infectoria SNB-GTC2402 and identified by spectroscopic analysis. As in pyrrocidines A and B, this compound is a cis-substituted decahydrofluorene with a quaternary carbon at C-5 and opposite stereochemistry at C-8 corresponding to C-6 of pyrrocidines A and B.© 2013 Elsevier Ltd. All rights reserved.
Keywords: Antimicrobials; Cytotoxic metabolites; Functional chemodiversity; Leaf endophytes; Lewia; Pyrrocidine C
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Cottet, K., Genta-Jouve, G., Fromentin, Y., Odonne, G., Duplais, C., Laprévote, O., et al. (2014). Comparative LC-MS-based metabolite profiling of the ancient tropical rainforest tree Symphonia globulifera. Phytochemistry, 108, 102–108.
Abstract: In the last few years, several phytochemical studies have been undertaken on the tropical tree Symphonia globulifera leading to the isolation and characterisation of several compounds exhibiting antiparasitic activities against Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani. The comparative LC-MS based metabolite profiling study conducted on the tree led to the identification of compounds originating from specific tissues. The results showed that renewable organs/tissues can be used as the starting material for the production of polycyclic poly-prenylated-acylphloroglucinols, therefore reducing impacts on biodiversity. This study also underlined the lack of knowledge on the secondary metabolites produced by S. globulifera since only a small number of the total detected features were putatively identified using the database of known compounds for the species.
Keywords: Kendrick mass defect; Lc-Ms; Plant organs; Symphonia globulifera; Untargeted metabolomics; Symphonia globulifera
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Cachet, N., Ho-A-Kwie, F., Rivaud, M., Houel, E., Deharo, E., Bourdy, G., et al. (2012). Picrasin K, a new quassinoid from Quassia amara L. (Simaroubaceae). Phytochem. Lett., 5(1), 162–164.
Abstract: A new quassinoid Picrasin K 1 was isolated from a decoction made of Quassia amara leaves, traditionally used in French Guyana to treat malaria. The structure and relative stereochemistry of 1 was determined through extensive NMR analysis. Picrasin K showed a low activity against Plasmodium falciparum in vitro (IC 50 = 8 μM), and a similar low activity on human cancerous cells line (IC 50 = 7 μM on MCF-7 cells line). © 2011 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
Keywords: Malaria; P. falciparum; Quassia amara; Quassinoids; Simaroubaceae
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Anouhe, J. - B. S., Adima, A. A., Niamké, F. B., Stien, D., Amian, B. K., Blandinieres, P. - A., et al. (2015). Dicorynamine and harmalan-N-oxide, two new β-carboline alkaloids from Dicorynia guianensis Amsh heartwood. Phytochemistry Letters, 12, 158–163.
Abstract: Abstract The chemical investigations of Dicorynia guianensis heartwood led to the isolation of four new indole alkaloids for the first time in this plant. Compound (1) identified as spiroindolone 2′,3′,4′,9′-tetrahydrospiro [indoline-3,1′pyrido[3,4-b]-indol]-2-one, and compound (3) described as nitrone 1-methyl-4,9-dihydro-3H-pyrido [3,4-b] indole 2-oxide and were isolated for the first time as natural products. ABTS antioxidant activity guided their isolation. © 2015 Published by Elsevier B.V. on behalf of Phytochemical Society of Europe.
Keywords: ABTS antioxidant; Biogenesis; Dicorynia guianensis; Nitrone; Spiroindolone
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Engel, J., Brousseau, L., & Baraloto, C. (2016). GuiaTreeKey, a multi-access electronic key to identify tree genera in French Guiana. PhytoKeys, 68(1), 27–44.
Abstract: The tropical rainforest of Amazonia is one of the most species-rich ecosystems on earth, with an estimated 16000 tree species. Due to this high diversity, botanical identification of trees in the Amazon is difficult, even to genus, often requiring the assistance of parataxonomists or taxonomic specialists. Advances in informatics tools offer a promising opportunity to develop user-friendly electronic keys to improve Amazonian tree identification. Here, we introduce an original multi-access electronic key for the identification of 389 tree genera occurring in French Guiana terra-firme forests, based on a set of 79 morphological characters related to vegetative, floral and fruit characters. Its purpose is to help Amazonian tree identification and to support the dissemination of botanical knowledge to non-specialists, including forest workers, students and researchers from other scientific disciplines. The electronic key is accessible with the free access software Xper2, and the database is publicly available on figshare: https://figshare.com/s/75d890b7d707e0ffc9bf (doi: 10.6084/m9.figshare.2682550). © Julien Engel et al.
Keywords: Amazonia; Electronic key; French Guiana; Morphological characters; Neotropics; Trees identification; Xper2
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Khia, A., Ghanmi, M., Satrani, B., Aafi, A., Aberchane, M., Quaboul, B., et al. (2014). Effect of provenance on the chemical and microbiological quality of essential oils of Rosmarinus officinalis L. in Morocco. Phytotherapie, 12(6), 341–347.
Abstract: This study is an assessment of the chemical quality and evaluation of antibacterial and antifungal activity of rosemary’s essential oils from three regions of Morocco (Rchida and Berkine/Eastern Morocco and Aknoul/North East of Morocco. The essential oils obtained by hydrodistillation of the leaves and young twigs of rosemary, were analyzed by GC / FID and GC/ MS. These essential oils are characterized by the presence of α and β-pinene, camphene, 1,8-cineole and camphor compounds. The quality of these essential oils met the AFNOR NF ISO 4730 rosemary Morocco kind (1,8-cineole). The evaluation of the antimicrobial activity of essential oils of Rosmarinus officinalis showed low efficacy against microorganisms tested which were all inhibited from 1/100 v/v except for Penicillium expansum whose growth was stopped at the concentration 1/250 v/v.
Keywords: Antibacterial; Antifungal activity; Chemical composition; Essential Oil; Provenance; Rosmarinus officinalis
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Castro, H., Fortunel, C., & Freitas, H. (2010). Effects of land abandonment on plant litter decomposition in a Montado system: relation to litter chemistry and community functional parameters. Plant Soil, 333(1-2), 181–190.
Abstract: Changes in land use and subsequent shifts in vegetation can influence decomposition through changes in litter quality (chemistry and structure) and alterations of soil temperature and moisture. Our aim was to study the effects of land abandonment on litter decomposition in a Mediterranean area of Montado, South Portugal. We tested the hypothesis that decomposition tends to slow down with abandonment, as woody species, richer in lignified structures, replace herbaceous species. We assessed the decomposition of community litter in situ using litterbag technique. To test the influence of local conditions, we simultaneously incubated a standard litter in situ. Our results showed that the shift from herbaceous to shrub-dominated communities lead to decreased decomposition rates. Changes in litter decomposition were primarily driven by changes in litter quality, even though the uneven pattern of litter mass loss over the experiment might reveal an effect from possible differences in microclimate. Shrub litter had higher nutrient content than herbaceous litter, which seemed to favour higher initial decomposition rates, but lower decomposition rate in the longer term. Shrubs also contribute to woody litter, richer in lignin, and secondary compounds that retard decomposition, and may play a role in increasing pools of slowly decomposing organic matter.
Keywords: Ecosystem processes; Land use change; Leaf dry matter content; Life form; Litter quality; Mediterranean
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Tremolieres, M., Noel, V., & Herault, B. (2009). Phosphorus and nitrogen allocation in Allium ursinum on an alluvial floodplain (Eastern France). Is there an effect of flooding history? Plant Soil, 324(1-2), 279–289.
Abstract: The change in phosphorus and nitrogen content in a common geophyte spring species, Allium ursinum, is studied in alluvial forests in relation to three flooding histories related to river regulation: (1) annually flooded, (2) unflooded for 30 years, and (3) unflooded for 200 years. Flood suppression leads to a reduction of available P soil content as well as decreasing the biomass and the amount of phosphorus in plants, but has no significant effect on N plant content. Plant N:P ratio increases with the suppression of floods and is primarily driven by soil N:P ratios, in turn markedly linked to the total nitrogen in the soil. We highlighted a lower nutrient accumulation in leaves during plant growth in unflooded forests. Overall, our results suggest that P was the main limiting factor in unflooded forests while nitrogen was the main limiting factor in annually flooded forests. Flood suppression strongly affects the morphology and nutrient uptake by Allium ursinum and thus nutrient cycling in riverine forests.
Keywords: Allium ursinum; Flooding history; Nitrogen; Nutrient bioavailability; Phosphorus; Rhine
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Brechet, L., Ponton, S., Roy, J., Freycon, V., Couteaux, M. M., Bonal, D., et al. (2009). Do tree species characteristics influence soil respiration in tropical forests? A test based on 16 tree species planted in monospecific plots. Plant Soil, 319(1-2), 235–246.
Abstract: The high spatial variability of soil respiration in tropical rainforests is well evaluated, but influences of biotic factors are not clearly understood. This study underlines the influence of tree species characteristics on soil respiration across a 16-monospecific plot design in a tropical plantation of French Guiana. A large variability of soil CO2 fluxes was observed among plots (i.e. 2.8 to 6.8 μmol m(-2) s(-1)) with the ranking being constant across seasons. There were no significant relationships between soil respiration and soil moisture or soil temperature, neither spatially, nor seasonally. The variability of soil respiration was mainly explained by quantitative factors such as leaf litterfall and basal area. Surprisingly, no significant relationship was observed between soil respiration and root biomass. However, the influence of substrate quality was revealed by a strong relationship between soil respiration and litterfall P (and litterfall N, to a lesser extent).
Keywords: Fine root; Litter quality; Nutrient cycling; Plant soil interactions; Soil respiration; Tropical plantations
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