Jean Costa

Chemical composition of myrtle leaf essential oil from Corsica (France)

Abstract Collective and individual samples of myrtle leaf oil from Corsica were analyzed by GC, GC/MS and Carbon-13 NMR spectroscopy. Corsican myrtle was found to contain α-pinene (47.9–59-5%) and 1,8-cineole (19.8–28.1%) as major components. It belongs to the α-pinene/l,8-cineole chemotype.

Composition of Helichrysum italicum (Roth) G. Don fil. subsp. italicum essential oils from Corsica (France)

The components of essential oils of Helichrysum italicum subsp. italicum growing in Corsica were investigated by the combination of GC and GC–MS. In a first part, nine commercial and laboratories-prepared samples were analysed and Corsican oils were found to contain neryl acetate as predominant compound, with amounts from 15.8% (from plants in stage of early shoots) to 42.5% (in full flowering period). In a second part, we sampled Helichrysum italicum subsp. italicum from three locations over the growth cycle of the plant. Significant variations were observed in the concentration of the main constituents, pointing out a chemical composition of oils produced from plants in early shoots (higher amounts of ketones and β-diketones) different from that obtained from samples harvested in the stages of flowering (higher contents of neryl acetate). Copyright

Comparison of liquid-liquid extraction with headspace methods for the characterization of volatile fractions of commercial hydrolats from typically Mediterranean species

Chemical composition of volatile fractions of nine commercial hydrolats and corresponding essential oils obtained using an industrial process were studied. The hydrolat volatile fractions were reported for the first time. A comparative study of those obtained, on the one hand, by liquid-liquid extraction (LLE) and, on the other hand, using five solid-phase microextraction (SPME) fibers and also purge-and-trap-automatic thermal desorption (P&T-ATD) was conducted with analysis performed by GC and GC/MS. The use of various techniques has resulted in a change of chromatographic profile of the hydrolat volatile fractions. Quantitative differences were established between chemical compositions of headspace and those obtained by a conventional method (LLE). Statistical analyses were carried out to summarize the results.

Composition and variability of the essential oil of Stachys glutinosa L. from Corsica (France)

The constituents of the essential oil of Stachys glutinosa L. were investigated for the first time. In a first part, we studied a collective oil following a methodology which combined chromatographic techniques (CC, GC) with spectroscopic techniques (MS, 13C-NMR). Sixty-four constituents (91% of the total composition) were identified. The major compounds were terpinen-4-ol (13.1%), α-pinene (10.1%), α-terpineol (8.4%), β-phellandrene (6.8%) and γ-terpinene (6.1%). In a second part, we investigated 53 oil samples obtained from individual plants collected widely in Corsica, by GC–RI and GC–MS. The essential oils of S. glutinosa displayed a wide infraspecific chemical variability.

Phylogeography of Cistus creticus L. on Corsica and Sardinia inferred by the TRNL-F and RPL32-TRNL sequences of cpDNA

2009 Elsevier Inc. All rights reserved.

Composition of the Essential Oil of Cistus ladaniferus L. Cultivated in Corsica (France)

The essential oil of Cistus ladaniferus L., obtained from plants of Spanish origin grown in Corsica, was investigated by 13C-NMR spectroscopy (identification of components) and GC (quantification). First, a bulk sample was analysed and 45 constituents were identified. The main components were α-pinene (39%), viridiflorol (11.8%), ledol (3.3%) and bornyl acetate (3.1%). The occurrence of cyclosativene, γ-cadinene, (E)-β-farnesene and β-eudesmol in the essential oil of Cistus ladaniferus is reported here for the first time. Then, in order to study the chemical variability of individual oils, we examined 20 samples. α-Pinene (11.1–47.4%) was the most abundant component in 18 of the 20 samples, followed by trans-pinocarveol (4.4–10.9%) and viridiflorol (4.7–10.7%). Two samples exhibited a different chemical composition, not as yet described, characterized by the predominance of viridiflorol (20–22.6%), ledol (6.4–6.7%) and trans-pinocarveol (5.4–8.6%).

Jatrophane Diterpenes as Inhibitors of Chikungunya Virus Replication: Structure–Activity Relationship and Discovery of a Potent Lead

Bioassay-guided purification of an EtOAc extract of the whole plant of Euphorbia amygdaloides ssp. semiperfoliata using a chikungunya virus-cell-based assay led to the isolation of six new (1-4, 9, and 10) and six known (5-7, 8, 11, and 12) jatrophane esters. Their planar structures and relative configurations were determined by extensive spectroscopic analysis, and their absolute configurations by X-ray analysis. These compounds were investigated for selective antiviral activity against chikungunya virus (CHIKV), Semliki Forest virus, Sindbis virus, and HIV-1 and HIV-2 viruses. Compound 3 was found to be the most potent and selective inhibitor of the replication of CHIKV and of HIV-1 and HIV-2 (EC50 = 0.76, IC50 = 0.34 and 0.043 μM, respectively). A preliminary structure-activity relationship study demonstrated that potency and selectivity are very sensitive to the substitution pattern on the jatrophane skeleton. Although replication strategies of CHIK and HIV viruses are quite different, the mechanism of action by which these compounds act may involve a similar target for both viruses. The present results provide additional support for a previous hypothesis that the anti-CHIKV activity could involve a PKC-dependent mechanism.

Delineation of vine parcels by segmentation of high resolution remote sensed images

Field delineation is an essential preliminary step for the design of management maps for grape production. In this paper, we propose a new algorithm for the segmentation of vine fields based on high-resolution remote sensed images. This algorithm takes into account the textural properties of vine images. It leads to the computation of a textural attribute on which a simple thresholding operation allows to discriminate between vine field and non-vine field pixels. The feasibility of the automatic delineation is illustrated on a range of vineyard images with various inter-row distances, grass covers, perspective distortions and side perturbations. In most cases it produces precise delineation of field borders while the parcel under consideration remains separate from the rest of the image.

Free flavonoid aglycones from Thymus herba barona and its monoterpenoid chemotypes

From the diethyl ether extracts of the aerial parts of Thymus herba barona, the flavanones eriodictyol, naringenin and the flavones luteolin, sorbifolin, thymusin, cirsiliol, apigenin, sideritoflavone, cirsimaritin, cirsilineol, xanthomicrol, 8-methoxycirsilineol and genkwanin were isolated and characterized. This is the first report of sorbifolin and cirsiliol in the genus Thymus. The distribution of these flavonoids in the seven terpenoid chemotypes of T. herba barona growing in Corsica was studied and the chemotaxonomic implications of this data discussed.

Chemical and genetic differentiation of Corsican subspecies of Teucrium flavum L.

Corsica Island exhibited the particularity to display Teucrium flavum subsp. glaucum and subsp. flavum on the same territory with the same bioclimatic conditions. For the first time, volatile components extracted from aerial parts and genetic diversity of both Corsican T. flavum L. subspecies have been investigated through (i) the characterization of the chemical composition of essential oils and (ii) the study of three polymorphic genetic markers. Chemical analysis were performed using combination of capillary GC/RI, GC-MS after fractionation on column chromatography and the definition of the genetic structure were carried out using two chlororoplast markers (RPL32-TRNL and TRNL-F) and ribosomal nuclear markers (ITS region). According to statistical analysis, both subspecies were clearly distinguished by the chemical and genetic studies. Chemical compositions of oils from both subspecies were qualitatively similar but they differed by the normalized% abundances of their major components; oils from subsp. flavum were dominated by large amounts of hydrocarbon monoterpenes while oils obtained from subsp. glaucum were characterized by higher amounts of oxygenated compounds. The genetic analysis divided T. flavum L. populations in two groups, the first displayed subsp. glaucum populations and the latter group exhibited subsp. flavum populations. The presence of two groups is weakly consistent with chemical differentiation. These data suggest that the differences in the volatile composition of the two T. flavum subspecies depends more on the genetic background and less on environmental factors.