Comparative chemometric analyses of geographic origins and compositions of lavandin var. Grosso essential oils by mid infrared spectroscopy and gas chromatography

Lavandin, a sterile hybrid of Lavandula angustifolia P. Mill. × Lavandula latifolia (L.f.) Medikus (Lamiaceae) is a plant widely cultivated for essential oil production in the South of France. Chemometric treatment by mid-infrared (MID-IR) spectroscopy data was assessed for the differentiation of Grosso Lavandin Essential Oils of Controlled Area (GLEOCA) and results were compared to those obtained by gas chromatography for MID-IR short time technique validation. The quantification of the main 13 hydrocarbons and oxygenated compounds generally controlled by industrial perfumers in GLEOCA samples (n = 83) of three geographic origins: “Simiane”, “Puimoisson” (with two producers) and “Richerenches” and their classification were successfully obtained by partial least square discriminant analysis (PLS-DA) by comparison with gas chromatography. The best prediction results were obtained using first derivate spectral data in the 1800-700 cm⁻¹ range. The spectroscopic interpretation of regression vectors showed that each geographic origin was correlated to components of GLEOCA. Chemometric MID-IR spectra treatments allowed us to obtain similar results than those obtained by time consuming analytical techniques such as GC and therefore constitute a robust and help fast method for authentication of GLEOCA and should be extended to other essential oils for authentication of geographic origin.     

Synthesis and spectroscopic examination of various substituted 1,3-dibenzoylmethane, active agents for UVA/UVB photoprotection

We describe the synthesis of eighteen variously substituted 1,3- dibenzoylmethane (1,3-DBM) and their change in absorption spectra depending of the nature of donor or acceptor substituents on one or the two aromatic moieties. These compounds were prepared in two steps starting from the corresponding acetophenones, phenol and benzoyl chlorides. The phenyl benzoate was obtained by condensation of benzoyl chloride with phenol in a classical way. Stirring of the phenyl benzoate and acetophenone in DMSO with powdered sodium hydroxide for a few minutes gave the dibenzoylmethane in yields depending on substituents on the phenyl rings. Changes in absorption of UVA/UVB sunlight of these molecules were observed according to the nature and the position of substituents on the phenyl rings. Molecules 2b (1-phenyl-3-(3,4,5-trimethoxyphenyl)-1,3-propanedione), 2d (1-(3,4-dimethoxyphenyl)-3-phenyl-l,3-propanedione), 2e (1-(2,3-dimethoxyphenyl)-3-phenyl-l,3-propanedione) and 2f (1-(2,3,4-trimethoxyphenyl)-3-phenyl-l,3-propanedione) were the most interesting for cosmetic applications because even after irradiation, they preserve their absorptive in UVA range and also in UVB range The other compounds are too photounstable and so can lose their protective effects. These results showed the lack of phototoxicity of these compounds and the possibility to use them as solar filters. Therefore, variously di- or tri methoxy 1,3-DBM are interesting molecules in term of photoprotection and open new prospects for UVA photostable filters.     

Marine bifunctional sphingolipids from the sponge Oceanapia ramsayi

During the course of our continuing studies on marine natural lipid products,two known sphingolipids have been isolated for the first time from a specimen of the marine sponge Oceanapia ramsayi collected at Itampolo on the west coast of Madagascar in the Indian Ocean. The structures were elucidated using NMR data and by comparison with literature data. The occurrence of these sphingolipids within other Oceanapia spp. is discussed.     

Netamines A-G: seven new tricyclic guanidine alkaloids from the marine sponge Biemna laboutei

In our continuing program to identify bioactive compounds from marine invertebrates, the MeOH/EtOAc (1:1) extract of three collections of the Madagascar sponge, Biemna laboutei, was found to be cytotoxic to a series of human tumor cells. From the two sponges, seven new guanidine alkaloids, designated netamines A-G (1-7), have been isolated and their structures elucidated. Compounds 3 and 4 were found to be cytotoxic against three tumor cells with GI₅₀ values in the micromolar range.     

Determination of sterol and triterpene alcohol acetates in natural products by reversed-phase liquid chromatography and gas chromatography-mass spectrometry

A partial separation of nine sterol acetates and seven triterpene alcohol acetates by reversed-phase liquid chromatography is described. Good results are obtained using acetonitrile-water (90:10, v/v) as mobile phase with an UV detector at 205 nm. The variation in sterol sensitivity shows that this technique is not suitable for quantitative analyses. A combination of this technique for the fractionation of the natural sterol mixture, gas-liquid chromatography for quantitation and gas chromatography-mass spectrometry for identification is necessary for the determination of sterol compounds contained in natural products. An example of the separation, identification and quantitation of sterol acetates from sunflower seed oil is given.     

Chemotypes of essential oil of unripe galls of Pistacia atlantica Desf. from Algeria

The essential oils (EOs) of unripe galls (from male and female plants) of a total number of 52 samples of Pistacia atlantica collected from different regions in Algeria were analysed by GC/MS and GC. The yields of the extraction of the EO by hydrodistillation vary from low to high values (0.08–1.89% v/w). The results of both methods of principal component analysis and hierarchical ascendant classification revealed the presence of two different chemotypes: α-pinene chemotype and α-pinene/sabinene/terpinen-4-ol chemotype.     

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