Audrey Kerdudo

Encapsulation of rutin and naringenin in multilamellar vesicles for optimum antioxidant activity

Rutin and naringenin, two phenolic compounds with antioxidant properties were encapsulated in lipid-based onion-type multilamellar vesicles (MLVs). After vesicles formation, the free, adsorbed/encapsulated analytes were well separated with size exclusion chromatography (SEC), and rutin and naringenin were quantified with UV-HPLC at 258 nm and 290 nm. A mathematical model was developed to separately calculate the encapsulation and the adsorption yields of both phenols. Naringenin was shown to be poorly encapsulated (<10%) but highly adsorbed on MLVs surface (>60%) whatever MLVs composition. Conversely, rutin showed high encapsulation efficiency (>60%). Entrapment of rutin was proved to be efficient since no leak was observed within 30 days in concentrated MLVs phase, while 16.0±0.3% of rutin was still encapsulated after 30 days when MLVs were diluted in water. Free rutin broke up into quercetin while the encapsulated one remained stable. DPPH assay confirmed that only free and adsorbed rutin participated in antioxidant activity.

New insights in the chemical composition of benzoin balsams.

Benzoin balsam is an anthropic exudate obtained from the bark of several species of Styrax trees that is mainly used as a perfume fixative as well as a flavouring agent. Benzoe tonkinensis Laos (also commercialized under the denomination Siam benzoin balsam) displaying characteristic vanilla notes and already being largely used to flavour all kinds of edible goods, was intended to be proposed by Agroforex Company to the Codex Committee on Food Additives for evaluation as a food additive. For this purpose, the present paper reports the phytochemical characterisation of both the volatile and non-volatile fractions of benzoin balsams and the quantitation of some of the major components by gas and liquid chromatography techniques. Four coniferyl and two morinol derivatives were characterised for the first time in Benzoe tonkinensis Laos. Finally, two liquid chromatographic methods used to easily discriminate Siam from Sumatra balsam (also known as Benzoe sumatranus Indonesia) were developed.

Essential oil composition and biological activities of Petiveria alliacea L. from Martinique

The volatile constituents obtained from the essential oil using hydrodistillation of the aerial parts of Petiveria alliacea L. growing in Martinique (F.W.I.: French West Indies), were examined by a combination of gas chromatography/flame ionization detection (GC/FID) and GC–mass spectrometry (GC–MS) techniques. Fifty-one components representing 89.1–98.1% of the essential oil total GC/FID chromatogram were identified. The most abundant compounds were toluenethiol (2.3–23.0%), phytol (6.4–40.0%) dibenzyldisulfide (13.2–35.3%) and benzaldehyde (0.8–31.3%). In total, forty new components were characterized in P. alliacea oils. Higher content in sulfur compounds were quantified in P. alliacea oils collected during the rainy season than those collected during the dry season. Antimicrobial activity of the essential oil from plants collected in Prêcheur area was also investigated. Antibacterial and antifungal activities were observed against Aspergillus niger, Candida albicans, Staphylococcus aureus, Escherichia coli, Salmonella arizonae and Listeria innocua at 0.5% and against resistant strains of E. coli (J96) and S. aureus (1799) at 1.0%.

Chemical composition, antimicrobial and insecticidal activities of flowers essential oils of Alpinia zerumbet (Pers.) from Martinique Island

Alpinia species, used as ornamental plants and flavoring agents, are renowned for their therapeutic properties and their subsequent use in traditional medicines throughout the world. Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm. is the most common Alpinia species encountered in Martinique. Several essential oils (EOs) obtained by hydrodistillation of A. zerumbet flowers collected in various locations on the island at different seasons were analysed to evaluate the influence of the collection period and area on the EOs’ chemical compositions and to assess their bioactivity. A combination of GC‐FID and GC/MS techniques was used to examine the volatile constituents, leading to the identification of a total of 71 components accounting for 97.8 – 99.3% of the respective total GC‐FID areas: among them, nineteen compounds were characterized for the first time in A. zerumbet EOs. The antimicrobial activity of these EOs was assessed against eight bacterial, yeast and fungal strains and two multi‐resistant strains: some significant bacteriostatic and fungistatic activities of A. zerumbet flower oils were evidenced. Finally, an interesting insecticidal activity of the flower EO was highlighted for the first time against Aedes aegypti.

Essential oil composition and antimicrobial activity of Hyptis atrorubens Poit. from Martinique (F.W.I.)

Abstract The volatile constituents obtained by hydrodistillation of the aerial parts of Hyptis atrorubens Poit. growing in Martinique (F.W.I.: French West Indies) were analyzed by a combination of GC/FID and GC-MS. Plants from two different locations in Martinique (North and South) were studied. For the north location, two preparation methods were studied: hydrodistillation in 3L or 20 L reactors and steam distillation. Sixty components representing between 87.7% and 93.2% of the essential oil GC/FID chromatogram total area were identified. The most abundant compounds were caryophyllene oxide (from 5.0 to 31.5%), β-caryophyllene (from 4.7 to 32.6%), palmitic acid (from 2.0 to 9.5%), spathulenol (from 1.5 to 8.5%), α-copaene (from 4.5 to 6.9%), 2-tridecanone (from 0.0 to 6.1%) and phytol (from 2.3 to 4.8%). By comparison with the literature describing a first chemotype rich in Germacrene D and a second chemotype rich in limonene and estragole, in our study Germacrene D was only present at 1.1 and 2.1% in the northern oil. Limonene was present in the oil from 0.1 to 0.3%. Furthermore, no estragole was found in this essential oil. Antimicrobial activity of the essential oil from aerial parts of the plant was also investigated. Antibacterial and antifungal activities were observed against A. niger, C. albicans, S. aureus, E. coli, and B. cereus at 0.5%.