Isabelle Fouraste

Oregano: Chemical Analysis and Evaluation of Its Antimalarial, Antioxidant, and Cytotoxic Activities

GC-FID and GC-MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p-cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC50=2±0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC50=4.8±0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC50 of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.

Enrichment in specific soluble sugars of two eucalyptus cell-suspension cultures by various treatments enhances their frost tolerance via a noncolligative mechanism

A cell-suspension culture obtained from the hybrid Eucalyptus gunnii/Eucalyptus globulus was hardened by exposure to lower temperatures, whereas in the same conditions cells from a hybrid with a more frost-sensitive genotype, Eucalyptus cypellocarpa/Eucalyptus globulus, were not able to acclimate. During the cold exposure the resistant cells accumulated soluble sugars, in particular fructose and sucrose, with a limited increase in cell osmolality. In contrast, the cell suspension that was unable to acclimate did not accumulate soluble sugars in response to the same cold treatment. To an extent similar to that induced after a cold acclimation, frost-hardiness of the cells increased after a 14-h incubation with specific soluble sugars such as sucrose, raffinose, fructose, and mannitol. Such hardening was also observed for long-term cultures in mannitol-enriched medium. This cryoprotective effect of sugars without exposure to lower temperatures was observed in both the resistant and the sensitive genotypes. Mannitol was one of the most efficient carbohydrates for the cryoprotection of eucalyptus. The best hardiness (a 2.7-fold increase in relative freezing tolerance) was obtained for the resistant cells by the cumulative effect of cold-induced acclimation and mannitol treatment. This positive effect of certain sugars on eucalyptus freezing tolerance was not colligative, since it was independent of osmolality and total sugar content.

Acylated kaempferol glycosides from Laurus nobilis leaves

Abstract Laurus nobilis leaves yielded four non-polar flavonoids: kaempferol -3-O-α- l -(3″,4″- di -E-p- coumaroyl)-rhamnoside , kaempferol -3-O-α- l -(2″,4″- di -E-p- coumaroyl)-rhamnoside , kaempferol -3-O-α- l -(2″-E-p- coumaroyl)-rhamnoside and a new product kaempferol -3-O-α- l -(2″,4″- di -Z-p- coumaroyl)-rhamnoside . Structural elucidation was achieved by UV, 1D- and 2D-NMR experiments, mass spectrometry, acid hydrolysis and saponification.

Chemical study, antimalarial and antioxidant activities, and cytotoxicity to human breast cancer cells (MCF7) of Argania spinosa

INTRODUCTION In our work, we evaluate the potential antioxidant, antimalarial activity and also activity against human breast cancer cells (MCF7) of Argan fruit extracts using in vitro models to validate the traditional use of this plant. Its chemical composition was also studied to begin the understanding of its activities, waiting to find the structure-activity relationship. RESULTS Polyphenols (89.4-218.5 eqGallic acid (mg/g dry)), tannins (39.3-214.0 eqCatechin (mg/g dry)), flavonoids (3.4-11.1 eqQuercetin (mg/g dry)) and anthocyanins (0.74-10.92 eqCyanindin (mug/g dry)) were quantified. A good (ethyl acetate and decoction) and moderate (petroleum ether) antioxidant activity were obtained for DPPH (IC(50) 32.3-600.8 microg/ml) and ABTS (IC(50) 11.9-988.8 microg/ml) assays. In addition, we found a good antimalarial activity (IC(50) 35 to >100 microg/ml) and human breast cancer cells activity (IC(50) 42 to >100 microg/ml). CONCLUSIONS The ethyl acetate extract and the decoction show interesting antimalarial and antioxidant activities. The results indicate a good correlations between anthocyanins quantitiy and the potential antioxidant (R(2)=0.9867) and also to antimalarial activity (R(2)=0.8175).

A degraded limonoid from Fagaropsis glabra

Abstract The structure and absolute configuration of fraxinellonone isolated from Fagaropsis glabra was established as 3α-(3′-furanyl)-3α,7-dimethyl-4,5-dihydro-1,6-isobenzofurandione, by NMR and CD comparison with fraxinellone. Complete carbon assignments for fraxinellone and isofraxinellone were achieved by 13 C- 1 H COSY experiments.

Methyl-4 formyl-7 cyclopenta(c)pyranne isole apres hydrolyse acide de Viburnum tinus

Abstract Viburtinal (4-methyl-7-formylcyclopenta(c)pyrane), yet unknown, was obtained by acid hydrolysis of the esters extracted from Viburnum tinus . Its structure was deduced by spectroscopic methods.

Three clerodane diterpenoids from Croton eluteria Bennett

Three furanoid clerodanes have been isolated from the stem bark of Croton eluteria Bennett. Their structures have been established by spectroscopic methods. The compounds were named cascarillin B (7alpha-acetoxy-3,4,15,16-diepoxy-12-oxo-cleroda-13(16),14-dien-20-al), cascarillin C (7alpha-acetoxy-15,16,12,20-diepoxy-20-hydroxy-cleroda-3,4,13(16),14-triene) and cascarillin D (7alpha-acetoxy-3,4,15,16-diepoxy-cleroda-13(16),14-dien-20-al).

A New Iridoid Glucoside from African Avicennia Germinans

Abstract A new iridoid glucoside, namely 2′(4′′- hydroxycinnamoyl) mussaenosidic acid, has been isolated from the leaves of Avicennia germinans (Gabon) along with 2′-caffeoyl mussaenosidic acid. The structure of the new compound was established by spectroscopic methods.

Megastigmane and Iridoid glucosides from Avicennia Germinans: Two Isomeric Forms of an Iridoid

Abstract The iridoid 2′-coumaroyl mussaenosidic acid, isolated from Avicennia germinans (Avicenniaceae), was analysed by NMR and molecular modeling: two isomeric forms were confirmed. In addition, the known compound 1 (6S, 9R) roseoside was isolated for the first time from this species of Avicennia.

C-glycosylflavones from Galipea trifoliata

Abstract From the stem bark of Galipea trifoliata were identified swertisin, isoswertisin, 2″-O-xylosylisoswertisin, vicenin-2, schaftoside, isoschaftoside and two new compounds: 6,8 di-C-glucosylgenkwanin and 2‴-O-xylosyl-6,8-di-C-glucosylgenkwanin.