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Tabacchi, Raffaele
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Tabacchi, Raffaele
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Professeur.e émérite
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- PublicationAccès libreLichen extracts as raw materials in perfumery. Part 2: treemoss(2009)
- PublicationAccès libreLichen extracts as raw materials in perfumery. Part 1: oakmoss(2009)
- PublicationAccès libreStereoselective Synthesis of cis- and trans-3,4-Dihydro-3,4,8-trihydroxynaphthalen-1(2H)-one(2009)
- PublicationMétadonnées seulementComponents from Sri Lankan Piper betle L. leaf oil and their analogues showing toxicity against the housefly, Musca domestica(2007)
; The essential oil extracted from Piper betle L. leaf using pilot plant steam distillation was tested against the adult housefly, Musca domestica, for insecticidal activity. LC50 values at the end of 24 and 48 h exposure periods were 10.3 and 8.7 mg/dm(3), respectively. Ceylon citronella oil (Cymbopogon nardus) used as a standard showed LC(50)s of 26.5 and 24.2 mg/dm(3) for the same exposure periods. Bioassay-guided fractionation of P. betle leaf oil revealed safrole and eugenol as the active principles against M. domestica, safrole showing LC50 values of 4.8 and 4.7 mg/dm(3), and eugenol 7.3 and 6.2 mg/dm(3) for the 24 and 48 h exposure periods, respectively, while citronellal (synthetic standard) showed equal LC50 values of 14.3 mg/dm(3) for the same exposure periods. Using safrole as the starting compound, eight analogues were prepared to study structure-activity relationships. Among the eight analogues, dihydrosafrole gave almost equal mortality at LC50 4.7 mg/dm(3) as that of the parent compound safrole after 24 and 48 h exposure, but isosafrole was twice as active as safrole, showing LC50 values of 2.3 and 2.2 mg/dm(3) for the 24 and 48 h exposure periods. Our GC-MS studies on Sri Lankan P. betle leaf oil show that it contains safrole (52.7%), allyllpyrocatechol diacetate (15.4%), eugenol (6.4%) and eugenyl acetate (5.8%) as the major components. Here we also present the GC-MS profile of fractions of Sri Lankan P. betle leaf oil. Copyright (c) 2006 John Wiley & Sons, Ltd. - PublicationAccès libreComponents from Sri Lankan Piper betle L. leaf oil and their analogues showing toxicity against the housefly, Musca domestica(2007)
; The essential oil extracted from Piper betle L. leaf using pilot plant steam distillation was tested against the adult housefly, Musca domestica, for insecticidal activity. LC50 values at the end of 24 and 48 h exposure periods were 10.3 and 8.7 mg/dm3, respectively. Ceylon citronella oil (Cymbopogon nardus) used as a standard showed LC50s of 26.5 and 24.2 mg/dm3 for the same exposure periods. Bioassay-guided fractionation of P. betle leaf oil revealed safrole and eugenol as the active principles against M. domestica, safrole showing LC50 values of 4.8 and 4.7 mg/dm3, and eugenol 7.3 and 6.2 mg/dm3 for the 24 and 48 h exposure periods, respectively, while citronellal (synthetic standard) showed equal LC50 values of 14.3 mg/dm3 for the same exposure periods. Using safrole as the starting compound, eight analogues were prepared to study structure–activity relationships. Among the eight analogues, dihydrosafrole gave almost equal mortality at LC50 4.7 mg/dm3 as that of the parent compound safrole after 24 and 48 h exposure, but isosafrole was twice as active as safrole, showing LC50 values of 2.3 and 2.2 mg/dm3 for the 24 and 48 h exposure periods. Our GC–MS studies on Sri Lankan P. betle leaf oil show that it contains safrole (52.7%), allylpyrocatechol diacetate (15.4%), eugenol (6.4%) and eugenyl acetate (5.8%) as the major components. Here we also present the GC–MS profile of fractions of Sri Lankan P. betle leaf oil. - PublicationAccès libreBafoudiosbulbins A, and B, two anti-salmonellal clerodane diterpenoids from Dioscorea bulbifera L. var sativa(2006)
; ; Lontsi, DavidTwo clerodane diterpenoids, Bafoudiosbulbins A 1, and B 2, together with five known compounds: tetracosanoic acid, 1-(tetracosanoyl)-glycerol, trans-tetracosanylferulate, β-sitosterol and 3-O-β-d-glucopyranosyl-β-sitosterol were isolated from the tubers of Dioscorea bulbifera L. var sativa. Their structures were established by spectroscopic methods (1D and 2D-NMR, MS) and X-ray crystallographic diffraction analysis of compound 1. The CH2Cl2-soluble portion of the crude extract and the two clerodanes were screened for anti-bacterial activity using both agar diffusion and broth dilution techniques against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella typhi, Salmonella paratyphi A and Salmonella paratyphi B. They both showed significant activities against P. aeruginosa, S. typhi, S. paratyphi A and S. paratyphi B. - PublicationAccès libreIsoflavonoid exudation from white lupin roots is influenced by phosphate supply, root type and cluster-root stage(2006)
; Abou-Mansour, Eliane• The internal concentration of isoflavonoids in white lupin (Lupinus albus) cluster roots and the exudation of isoflavonoids by these roots were investigated with respect to the effects of phosphorus (P) supply, root type and cluster-root developmental stage.
• To identify and quantify the major isoflavonoids exuded by white lupin roots, we used high-pressure liquid chromatography (HPLC) coupled to electrospray ionization (ESI) in mass spectrometry (MS).
• The major exuded isoflavonoids were identified as genistein and hydroxygenistein and their corresponding mono- and diglucoside conjugates. Exudation of isoflavonoids during the incubation period used was higher in P-deficient than in P-sufficient plants and higher in cluster roots than in noncluster roots. The peak of exudation occurred in juvenile and immature cluster roots, while exudation decreased in mature cluster roots.
• Cluster-root exudation activity was characterized by a burst of isoflavonoids at the stage preceding the peak of organic acid exudation. The potential involvement of ATP-citrate lyase in controlling citrate and isoflavonoid exudation is discussed, as well as the possible impact of phenolics in repelling rhizosphere microbial citrate consumers. - PublicationAccès libreWhite lupin has developed a complex strategy to limit microbial degradation of secreted citrate required for phosphate acquisition(2006)
; ; Martinoia, EnricoWhite lupins (Lupinus albus L.) respond to phosphate deficiency by producing special root structures called cluster roots. These cluster roots secrete large amounts of carboxylates into the rhizosphere, mostly citrate and malate, which act as phosphate solubilizers and enable the plant to grow in soils with sparingly available phosphate. The success and efficiency of such a P-acquisition strategy strongly depends on the persistence and stability of the carboxylates in the soil, a parameter that is influenced to a large extent by biodegradation through rhizosphere bacteria and fungi. In this study, we show that white lupin roots use several mechanisms to reduce microbial growth. The abundance of bacteria associated with cluster roots was decreased at the mature state of the cluster roots, where a burst of organic acid excretion and a drastic pH decrease is observed. Excretion of phenolic compounds, mainly isoflavonoids, induced fungal sporulation, indicating that vegetative growth, and thus potential citrate consumption, is reduced. In addition, the activity of two antifungal cell wall-degrading enzymes, chitinase and glucanase, were highest at the stage preceding the citrate excretion. Therefore, our results suggest that white lupin has developed a complex strategy to reduce microbial degradation of the phosphate-solubilizing agents. - PublicationAccès libreGeographic origin of European Emmental. Use of discriminant analysis and artificial neural network for classification purposes(2005)
; Bosset, Jacques-OlivierThe goal of this work was to classify European Emmental cheeses according to their geographic origin using analytical approaches. Twenty-five analytical parameters (factors) were measured in 183 samples. Results were combined by multivariate statistical analysis. Discriminant analysis (DA) and an artificial neural network (ANN) delivered similar results when all regions and factors were included; 95% and 91%, respectively, of the samples were correctly classified in the validation procedure. To reduce the analytical costs and the risk of overfitting, a DA based on a selection of only 11 factors was calculated. In this case, the Jackknifed validation delivered 95% correct assignments. Finally, a system was optimised to discriminate between the Swiss samples and cheeses from other regions. Building a new model for each of the six pairs, Switzerland vs. another region, 100% correct classification could be achieved for the Swiss samples. - PublicationAccès libreGeographic origin of European Emmental cheese: Characterisation and descriptive statistics(2005)
; Bosset, Jacques-OlivierTo survey the authenticity of Emmental cheese from some of the main European countries of origin, samples of cheeses manufactured during winter (110 samples) and summer (73 samples) were collected. From a preliminary study, a series of promising analytical methods were selected and applied: total nitrogen, water soluble nitrogen (WSN), 12% TCA soluble nitrogen (TCA-SN), pH-value, volatile short-chain acids, chloride, organic acids, enterococci, obligate heterofermentative lactobacilli (OHL), Lactobacillus helveticus, sodium, copper, zinc, magnesium and stable isotope ratios (δ2H, δ13C, δ15N, δ34S). The data were analysed by univariate statistical methods according to the geographic origin and the season of production. Significant differences between the regions of origin were found for all parameters investigated (P≤0.001). Cheeses from some regions showed very specific properties. Seasonal differences were observed in certain regions for acetate, propionate, caproate, WSN, TCA-SN, pyruvate, OHL, zinc and δ13C levels.