Chemical Composition and Synergistic Potential of Mentha pulegium L. and Artemisia herba alba Asso. Essential Oils and Antibiotic against Multi-Drug Resistant Bacteria.

The essential oils were obtained by hydrodistillation from aerial parts of Mentha pulegium L. (M. pulegium L.) and Artemisia herba alba (A. herba alba) Asso. and analyzed by gas chromatography-flame ionization detector chromatograpy (GC-FID) and gaz chromatography-mass spectrometry (GC-MS). The antibacterial activities of the oils were determined by the disk diffusion method and a microdilution broth assay against six bacteria stains. The combinations of these essential oils with antibiotics were evaluated against two multi-drug-resistant bacteria strains: imipenem-resistant Acinetobacter baumannii (IRAB S3310) and methicillin-resistant Staphylococcus aureus (MRSA S19). The chemical analysis of M. pulegium essential oil revealed the presence of pulegone (74.8%) and neoisomenthol (10.0%). A. herba alba essential oil was characterized by camphor (32.0%), α-thujone (13.7%), 1,8-cineole (9.8%), ß-thujone (5.0%), bornéol (3.8%), camphene (3.6%), and p-cymene (2.1%). All strains tested except Pseudomonas aeruginosa were susceptible to these oils. The combinations of essential oils with antibiotics exerted synergism, antagonism, or indifferent effects. The best effect was observed with A. herba alba essential oil in association with cefoxitin (CX) against MRSA S19. However, for IRAB S3310, the strongest synergistic effect was observed with M. pulegium in association with amikacin (AK). This study demonstrated that M. pulegium and A. herba alba essential oils have antibacterial activities which could be potentiated by antibiotics especially in the case of IRAB S3310.

Chiroptical fingerprints to characterize lavender and lavandin essential oils.

Polarimetric HPLC detector was used to acquire chromatograms for lavender/lavandin essentials oils (EOs) on different chiral stationary phases. Amylose tris-(3,5-dichloro-phenylcarbamate) immobilized on silica allowed the best separation of the numerous chiral phytomarkers and was thus used to obtain a chiroptical fingerprint for 158 samples of French lavender/lavandin EOs. Samples from different varieties (Abrial, Fine, Grosso, Maillette, Matherone, Sumian and Super) were collected over three crop years (2012, 2013 and 2014), from four different locations in France (``Alpes-de-Haute-Provence'', ``Ardèche'', ``Drôme'' and ``Vaucluse'') to take into account seasonal and geographic origin variations. The combination of the polarimetric fingerprints and chemometrics was tested for varietal discrimination. We assessed the ability to discriminate the EOs samples and their variety by partial least squares-discriminant analysis (PLS-DA). This case study showed that liquid chromatography with polarimetric detector in tandem with chemometric analysis was efficient to differentiate the varietal origins of French lavender/lavandin EOs.

Variability of composition and effects of essential oils from Rhanterium adpressum Coss. & Durieu against mycotoxinogenic Fusarium strains.

The antifungal potency of the essential oils of Rhanterium adpressum was evaluated against four mycotoxigenic strains of the genus Fusarium. The essential oils were obtained, separately, by hydro-distillation of the aerial parts of R. adpressum (leaves and flowers). The parts were collected during the period of bloom (3 months) for 3 years. The GC-MS analysis revealed thirty-six compounds for the essential oils, divided into four classes of chemical compounds, with variable percentages according to the month of extraction. The monoterpene hydrocarbons form the main class in these oils. On the other hand, the highest percentages of the oxygenated compounds are observed in the samples collected during the month of May. The direct contact method was used to evaluate the antifungal activity of the essential oils. The activity can be attributed to their relatively high composition of oxygenated monoterpenes. Flowers extract showed strong inhibitory activity, with very interesting concentrations of IC50 and MIC for both tests on solid and liquid medium. The effect of these oils on the production of type B trichothecenes (TCTBs) was evaluated, showing a significant inhibitory effect on TCTBs production, for both extracts (leaves and flowers). The rates of inhibition were 66-97 and 76-100% of FX, 3-ADON and 15-ADON, respectively. The inhibition of fungal biomass and the production of TCTBs depended on the used concentration of the essential oils. These results suggest that the essential oils from R. adpressum are able to control the growth of the tested strains and their subsequent production of TCTB mycotoxins.

Artemisia arborescens Essential Oil Composition, Enantiomeric Distribution, and Antimicrobial Activity from Different Wild Populations from the Mediterranean Area.

Aerial parts of Artemisia arborescens were collected from different sites of the Mediterranean area (southwestern Algeria and southern Italy) and the chemical composition of their essential oil (EO) extracted by hydrodistillation was studied by both gas chromatography (GC) equipped with an enantioselective capillary column and GC/mass spectrometry (GC/MS). The EOs obtained were tested against several Listeria monocytogenes strains. Using GC and GC/MS, 41 compounds were identified, accounting for 96.0 - 98.8% of the total EO. All EOs showed a similar terpene profile, which was rich in chamazulene, ß-thujone, and camphor. However, the concentration of such compounds varied among the EOs. A. arborescens EO inhibited up to 83.3% of the L. monocytogenes strains, but the inhibitory spectrum varied among the EOs, with those from Algeria showing a higher inhibition degree than the Italian EOs. Such effect likely depended on the ketone (ß-thujone + camphor) content of the EO. The differences in the EO composition support the hypothesis that A. arborescens has at least two different chemotypes: a ß-thujone and a chamazulene type. The EO inhibitory spectrum indicates the A. arborescens EO as a valuable option in the control of the food-borne pathogens.

Analysis of the major chiral compounds of Artemisia herba-alba essential oils (EOs) using reconstructed vibrational circular dichroism (VCD) spectra: En route to a VCD chiral signature of EOs.

An unprecedented methodology was developed to simultaneously assign the relative percentages of the major chiral compounds and their prevailing enantiomeric form in crude essential oils (EOs). In a first step the infrared (IR) and vibrational circular dichroism (VCD) spectra of the crude essential oils were recorded and in a second step they were modelized as a linear weighted combination of the IR and VCD spectra of the individual spectra of pure enantiomer of the major chiral compounds present in the EOs. The VCD spectra of enantiomer of known enantiomeric excess shall be recorded if they are not yet available in a library of VCD spectra. For IR, the spectra of pure enantiomer or racemic mixture can be used. The full spectra modelizations were performed using a well known and powerful mathematical model (least square estimation: LSE) which resulted in a weighting of each contributing compound. For VCD modelization, the absolute value of each weighting represented the percentage of the associate compound while the attached sign addressed the correctness of the enantiomeric form used to build the model. As an example, a model built with the non-prevailing enantiomer will show a negative sign of the weighting value. For IR spectra modelization, the absolute value of each weighting represented the percentage of the compounds without of course accounting for the chirality of the prevailing enantiomers. Comparison of the weighting values issuing from IR and VCD spectra modelizations is a valuable source of information: if they are identical, the EOs are composed of nearly pure enantiomers, if they are different the chiral compounds of the EOs are not in an optically pure form. The method was applied on four samples of essential oil of Artemisia herba-alba in which the three major compounds namely (-)-α-thujone, (+)-ß-thujone and (-)-camphor were found in different proportions as determined by GC-MS and chiral HPLC using polarimetric detector. In order to validate the methodology, the modelization of the VCD spectra was performed on purpose using the individual VCD spectra of (-)-α-thujone, (+)-ß-thujone and (+)-camphor instead of (-)-camphor. During this work, the absolute configurations of (-)-α-thujone and (+)-ß-thujone were confirmed by comparison of experimental and calculated VCD spectra as being (1S,4R,5R) and (1S,4S,5R) respectively.

Effect of Maturation Degree on Composition of Fatty Acids and Tocopherols of Fruit Oil from Pistacia atlantica Growing Wild in Algeria.

Pistacia atlantica fruit oil has been used for a long time by local populations for culinary and medicinal purposes. In this study, the fatty acid composition and tocopherol content were determined in twelve samples of P. atlantica fruit oil at three stages of maturation (immature, intermediate maturity and mature) collected in three different sites from the region of Laghouat. The results indicated a significant difference between the oil of mature fruits (green and black) and the immature ones (light red), which were distinguished by richness in unsaturated fatty acids and tocopherols. The oil from fruits of intermediate maturity (dark red) seems to combine these properties with those of the mature group, including oil yields. Such data emphasize the value of this oil, which needs further investigation.

Chemical composition and antioxidant activity of seed oil of two Algerian date palm cultivars (Phoenix dactylifera).

The fatty acid composition of date seed oil from two different date palm (Phoenix dactylifera L.) cultivars, locally known as Degla-Baïdha and Tafezouine, were investigated. GC analysis revealed the presence of five dominant fatty acids: oleic C18:1 (46.51; 39.15%), lauric C12:0 (22.1; 28.5%), myristic C14:0 (10.7; 11.4%), palmitic C16:0 (9.6; 8.7%) and linoleic C18:2 (6.9; 6.1%). The oils was characterised by a low content of tocopherols (0.53; 1.41 µg/g). The antioxidant activity of the oils was investigated using the DPPH*(1,1-di-phenyl-2-picryl-hydrazyl) scavenging assay. The oils had a weak bleaching effect on DPPH* free radicals. This study showed that the qualities of the tested oils are highly comparable with those of some commercial seed oils of other plants. Furthermore, a statistical analysis using the hierarchy ascendant classification method was conducted in order to highlight the similarities and/or the differences regarding the contents of the main fatty acids found in some common plants and in the five most famous cultivars of Phoenix dactylifera of south eastern Algeria (Tafezouine, Degla-Baïdha, Deglet-Nour, Ghars, Tamdjouhert).

Oleodaphnoic acid and coriaceol, two new natural products from the stem bark of Wikstroemia coriacea.

Fractionation of the chloroform extract of Wikstroemia coriacea led to the isolation of two new compounds, oleodaphnoic acid (1), a guaiane-type sesquiterpenoid, and coriaceol (2), an 1,5-diphenyl-1-pentanone analogue, together with nine known compounds. The structures of 1 and 2 were elucidated by extensive spectroscopic data analysis. The known compounds were oleodaphnal (3), indicanone (4), (5R,8R,8aR)-3,8-dimethyl-4,5,6,7,8,8a-hexahydro-5-(1-methylethenyl)-2(1H)-azulenone, (5), 1,5 diphenyl-1-pentanone (6), (+)-3-hydroxy-1,5-diphenyl-1-pentanone (7), umbelliferone (8), daphnoretin (9), ß-sitostenone (10) and (-)-hinokinin (11).

The BH3-only protein Noxa is stimulated during apoptosis of chronic lymphocytic leukemia cells triggered by M2YN, a new plant-derived extract.

Deficiency of apoptosis is a hallmark of chronic lymphocytic leukemia (CLL) cells. M2Yn is a natural extract from plants of central Asia, identified for its antiangiogenic properties and its ability to block the migration of malignant cells. Here, we report that in vitro treatment of cells derived from CLL patients with M2Yn results in internucleosomal DNA fragmentation, phosphatidylserine externalization, mitochondrial membrane depolarization, caspase-3 activation and cleavage of the caspase substrate PARP-1. The extents of these effects depend on the patients and are mostly comparable to those of flavopiridol or hyperforin, two known plant-derived apoptosis inducers of CLL cells. M2Yn does not modulate Mcl-1 expression, while downregulation of this antiapoptotic protein is involved in the action of flavopiridol. By contrast, M2Yn, like hyperforin, upregulates the Noxa protein, possibly by inhibiting proteasomal activity. This BH3-only protein is known to trigger the activation of the pro-apoptotic protein Bak through displacement of the Mcl-1/Bak complex at the mitochondrial membrane, as actually observed here in M2Yn-treated cells. Our data, therefore, show that M2Yn can induce the caspase-dependent mitochondrial pathway of apoptosis in CLL cells via a mechanism resembling that of hyperforin. Our data also confirm that the BH3-only protein Noxa is a relevant target for CLL therapy.

Chemotypes of Pistacia atlantica leaf essential oils from Algeria.

The essential oils obtained by hydrodistillation of Pistacia atlantica Desf. leaves collected from different regions of Algeria were analyzed by GC and GC-MS. The essential oil was rich in monoterpenes and oxygenated sesquiterpenes. The major components were alpha-pinene (0.0-67%), delta-3-carene (0.0-56%), spathulenol (0.5-22%), camphene (0.0-21%), terpinen-4-ol (0.0-16%) and beta-pinene (0.0-13%). Among the various components identified, twenty were used for statistical analyses. The result of principal component analysis (PCA) showed the occurrence of three chemotypes: a delta-3-carene chemotype (16.4-56.2%), a terpinen-4-ol chemotype (10.8-16.0%) and an alpha-pinene/camphene chemotype (10.9-66.6%/3.8-20.9%). It was found that the essential oil from female plants (delta-3-carene chemotype) could be easily differentiated from the two other chemotypes corresponding to male trees.

Isolation and characterization of a new hispolone derivative from antioxidant extracts of Pistacia atlantica.

The quantification of the total phenolic compounds of Pistacia atlantica showed that the different parts of the tree are rich in natural phenolic compounds. The antioxidant tests proved that the phenolic extracts have a strong antioxidant activity. The positive correlation between the Trolox equivalent antioxidant capacity (TEAC) and the amount of phenolic compounds confirms their contribution to the antioxidant activity. Among the various phenolic compounds isolated and characterized by spectroscopic methods, a new natural antioxidant 1 (methyl 5-(3,4-dihydroxyphenyl)-3-hydroxypenta-2,4-dienoate) derived from hispolone 2 has been isolated from the mushroom Inonotus hispidus growing on Pistacia atlantica. Hispolone 2 (6-(3,4-dihydroxyphenyl)-4-hydroxyhexa-3,5-dien-2-one) and hispidin 3 (6-(2-(3,4-dihydroxyphenyl)vinyl)-4-hydroxy-2H-pyran-2-one) have been also identified using spectroscopic methods, including 2D-NMR and EI-MS.

Anthocyanin and flavonoid production from Perilla frutescens: pilot plant scale processing including cross-flow microfiltration and reverse osmosis.

Extraction and concentration at a pilot plant scale of anthocyanins and flavonoids from Perilla frutescens var. frutescens harvested in the Guangzhou area of China were investigated. The study of extraction efficiency using mineral acids and organic acids showed that 0.01 mol/L nitric acid was the most suitable to extract flavonoids from this slightly red leaf cultivar. The red extract contained 12 mg/L (as cyanidin equivalent) anthocyanins and other flavones. The multistep process included cross-flow microfiltration (CFM) with a ceramic type membrane, reverse osmosis (RO), and rotating evaporation (RE). The filtration fluxes were high and constant for CFM (150 L/h/m2 at 0.6 b) and for RO (22 L/h/m2 at 40 b). The red extract was concentrated 9.4 times by RO and then 5.4 times by RE. It contained 422 mg/L anthocyanins, representing 77% of the total extracted anthocyanin. The proportion of flavonoids was found unchanged during processing. The concentrated extract showed a pH of 2.7, and its free acidity was found to be 46% of the acidity added for extraction, because of the buffering capacity of the extract. At the concentration level reached, a crystallized deposit occurred and was identified as tartrate.