Bernadette Rezzonico

First Phytochemical Evidence of Chemotypes for the Seagrass Zostera noltii

The variability of the flavonoid content of two populations of Z. noltii from different geographical zones, i.e., the Bay of Arcachon and the Bay of Cadiz, was evaluated. Samples were collected in spring and autumn at the two sites, and extracts were prepared by maceration in water. The phenolic content was fully characterized using Nuclear Magnetic Resonance (NMR), UV and Liquid Chromatography-Mass Spectrometry (LC-MS), and the concentration of the individual phenolic was determined by quantitative High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD). The two populations show a strong geographical differentiation in their flavonoid content. The samples from Cadiz were dominated by apigenin 7-sulfate, which represents 71% (autumn collection) and 83% (spring collection) of the total flavonoids, whereas the samples from Arcachon were characterized by diosmetin 7-sulfate (85 and 93% of the total flavonoids). Structural elucidation of the individual phenolics was assigned using the complementary information from their spectral evidence. In addition, the results were confirmed by acid hydrolysis of the flavonoid sulfates, and comparison to synthetic standards obtained by sulfation of apigenin, diosmetin and luteolin. The results represent the first experimental evidence of the existence of chemotypes within the species Z. noltii.

The economic potential of beach-cast seagrass – Cymodocea nodosa: a promising renewable source of chicoric acid

Abstract Detrital and fresh specimens of the seagrass Cymodocea nodosa (Cymodoceaceae) from the Atlantic Ocean and Mediterranean Sea were screened for their phenolic content. For the first time, the major polyphenol was identified as chicoric acid (CA) by means of nuclear magnetic resonance, ultraviolet spectra, liquid chromatography/mass spectrometry, and comparison with standards. The CA content of the crude extracts was determined by quantitative high-performance liquid chromatography. The values found in the leaves ranged from 8.13 to 27.44 mg g-1 dw. The concentration was smaller in the rhizomes, with 0.31–3.70 mg g-1 dw. The phenolic profile was found to be similar whatever the geographical location in the Atlantic Ocean or the Mediterranean Sea. Considering the demonstrated therapeutic applications of CA, its high value on the nutraceutical market, and its rare occurrence in the plant kingdom, the high content found in C. nodosa detrital leaves makes this abundant biomass of interest for dietary and pharmaceutical applications.

Isolation of plumieride from Plumeria inodora

1) Phytochimie et Valorisation de la Biomasse (PhyValBio), Universite Bordeaux I, F 33405 Talence cedex, France,tel.: +33 5 40002290; fax: +33 5 40006422, e-mail: m.grignon-dubois@phyvalbio.u-bordeaux1.fr; 2) Instituto de Investigacionesde la Universidad de Los Andes, Merida, Venezuela. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 602-603,November-December, 2005. Original article submitted March 18, 2005. 730 0009-3130/05/4106-0730

Silicon-Assisted Ethoxycarbonylmethylation ofN-Methylquinolinium and Isoquinolinium Iodides

A new regioselective route to 2-ethoxycarbonylmethyl-1,2-dihydro-N-methylquinolines and 1-ethoxycarbonylmethyl-1,2-dihydro-N-methylisoquinolines is described starting from methylquinolinium or -isoquinolinium iodides and commercially available ethyltrimethylsilyl acetate (ETSA). The methylene carbanion was generated by fluorodesilylation using caesium fluoride. On exposure to air, the ethoxycarbonylmethyl adducts were oxidised, leading to the corresponding alkylidene derivatives 4 and 5, whereas 2a in solution led slowly to its regioisomer 6a.

Phenolic fingerprint of the seagrass Posidonia oceanica from four locations in the Mediterranean Sea: first evidence for the large predominance of chicoric acid

Abstract The phenolic fingerprint of the leaves of Posidonia oceanica collected from four different Mediterranean Sea regions was determined using a panel of analytical techniques. It was found to be dominated by caffeic tartrates, along with low amounts of coumaric and ferulic tartrates. Chicoric acid (CA) was unambiguously identified as the major phenolic compound, regardless of the sample or collection site. Caftaric acid (CAF) was the second most abundant phenolic, but in much lower average concentrations. These results contrast with most of the previous works, in which CA was not even mentioned. The dramatic influence of extract handling, as well as the importance of choosing the adequate criteria of identity to standards, was demonstrated. These results show the importance of analyzing the crude extract to avoid some of the major pitfalls in determining the phenolic fingerprints. This is the first report to identify and quantify CAF in the Posidoniaceae and to identify CA as the dominant phenolic in Posidonia leaves. The large accumulation of CA in both living (10.12–12.78 mg g-1 dw) and detrital leaves (2.49–12.11 mg g-1 dw) across large geographical scales is noteworthy. The lack of significant concentrations of flavonoids contrasts with other seagrass genera. Importantly, the phenolic signature of P. oceanica shows significant similarities to those of Cymodocea nodosa and Syringodium filiforme, both belonging to the Cymodoceaceae. These results are discussed in terms of metabolic pathways and phylogenetic relationships.

One-pot stereoselective synthesis of dimethanodibenzo[e,i][1,4]diazecines by a zinc-acetic acid promoted cascade reaction

Abstract The title compounds are interesting C 2 symmetrical diamines. They were prepared in a one-pot process by reacting quinaldines with a zinc-acetic acid mixture in THF solution. During this simple and stereoselective process, two CC bonds and 4 stereogenic centres are created under mild conditions. Influence of the concentration of reagents upon yields and intramolecular cyclization regiochemistry is demonstrated. Experiments using deuteriated acetic acid allowed a good understanding of these results.

PENTACYCLIC TRITERPENES FROM Sarcostemma clausum

A homologous series of alkanoic acid (C2–C5) esters of germanicol was isolated from the methanolic extract of Sarcostemma clausum, of which germanicol-3-propionate and 3-pentanoate have not been previously described in the literature. In addition, taraxasterol, multiflorenol, and bauerenol were also isolated for the first time from the genus Sarcostemma. Structures were elucidated by chemical and spectroscopic methods (NMR, IR, SM) and by comparison with literature data.

High Value-Added Biomolecules from Beach Waste of Marine Origin-Screening for Potential Candidates among Seagrass of the Cymodoceaceae Family

Method: Six species of seagrass belonging to the genera Syringodium, Cymodocea and Halodule were collected from their native habitat. The L-chiro-inositol content of the crude aqueous extracts prepared from different batches of Cymodocea nodosa flotsam was measured by quantitative H-NMR spectroscopy. High concentrations were found with values ranging from 22.2 to 35.0 mg.g plant dw. The presence of L-chiro-inositol in the tropical species C. rotundata, C. serrulata, Syringodium isoetifolium, and Halodule pinifolia was also characterized by qualitative NMR. The chicoric acid content of crude aqueous methanolic extracts prepared from C. rotundata, C. serrulata, S. isoetifolium, and Halodule pinifolia was determined by quantitative HPLC-DAD. The values found ranged from 0.39 to 6.15 mg.g dry weight. Chicoric acid was unambiguously identified as the major phenolic in S. isoetifolium, and Halodule pinifolia, while it was found in mixture with flavonol derivatives in C. rotundata and C. serrulata. Flavonol derivatives are also of interest for their bioactivity.