Naïm Ouaini

Chemical Composition and Antimicrobial Activity of the Essential Oil of Juniperus excelsa M.Bieb. Growing Wild in Lebanon

The essential oils (EOs) isolated from the leaves and twigs of Juniperus excelsa M.Bieb. growing wild in Lebanon were characterized, and their antimicrobial activity and antiradical capacity were evaluated. The EOs were obtained by hydrodistillation using a Clevenger‐type apparatus and characterized by GC and GC/MS analyses. The antimicrobial activity was evaluated by determining minimal inhibitory concentrations (MICs) against a Gram‐positive and a Gram‐negative bacterium, a yeast, and a dermatophyte with the broth microdilution technique.

Interaction of cucurbitacins with human serum albumin: Thermodynamic characteristics and influence on the binding of site specific ligands

Cucurbitacins (Cuc) are cytotoxic oxygenated triterpenes. Their binding to albumin may control their diffusion and consequently their biological effects. The specific binding site of Cuc to albumin is important to be defined as it could determine some of the drug interactions of the compounds. This paper deals with the interaction between human serum albumin and a series of four cucurbitacins (B, D, E and I) measured by fluorescence and circular dichroism spectroscopies. Cuc B and E at C25, are the acetylated forms of Cuc D and I. The binding parameters (K(a) and n) of Cuc B, D and E to albumin were determined at 288, 293, 298 and 303K. Cuc B possesses the higher binding constant (K(a)) values followed by Cuc E and D. The thermodynamic parameters DeltaH, DeltaG and DeltaS were calculated. They indicated hydrophobic and electrostatic interactions for Cuc B, hydrophobic interaction for Cuc E, hydrophobic and hydrogen bond interactions for Cuc D. In addition to bilirubin, Cuc B, D, and E increased the binding constant values for warfarin to albumin, whereas they did not affect the binding of other ligands of site I such as chloroform and salicylate. The increase of the K(a) values of warfarin and bilirubin was associated with an increase of the binding constant value of cucurbitacin to albumin. Cuc I did not bind to albumin and could be considered less capable to affect the interaction of ligands to albumin than Cuc B, D and E. CD spectra indicated that Cuc binding to HSA was not associated with substantial structural changes of the protein.

Effects of fertilizer industry emissions on local soil contamination: a case study of a phosphate plant on the east Mediterranean coast

Fugitive dust emission, transport and deposition from phosphate fertilizer industries may pose an environmental hazard to the surrounding environment, particularly to soil. This study is to evaluate such hazard by investigating the fate of airborne pollutants, their transfer from atmosphere to soil surface, and their contamination potential. Concentrations of elements were measured in soil samples. Elemental analyses were carried out using ICP-AES and ICP-MS. Analysis of speciation of trace elements, using a sequential extraction method, was performed on the plants raw material (apatite), product and waste (phosphate fertilizer and phosphogypsum). A model estimating local atmospheric dry deposition was formulated. Statistical analyses were performed on sample data. Measured phosphorus accumulated considerably to the north-east of the plant, mainly due to the prevailing wind and associated dry deposition. Results exhibited considerably above-threshold enrichments in potentially toxic, bio-available trace elements (Cd, Zn) (2.5–6.9, 295–506 mg kg−1) and radionuclide (U, 20–98.69 mg kg−1) within a major deposition area. Speciation results revealed Zn and Cd occurring predominantly in mobile phases within the pollution source materials. Dry deposition calculation showed extensive input fluxes of Sr, Zn, Cr, U, Ni and Cd. Significant correlation was established between measured trace elements concentrations and their calculated deposition fluxes. Phosphorus species were the principal carriers of trace elements in soils. The phosphate industry poses a serious soil pollution hazard, with deposited contaminants being potentially hazardous to plants and groundwater. This study serves as a basis to assess the phosphate industrys risk impact on soil, while it introduces combined analytical methodologies for such assessment.

Stability of cucurbitacin E in human plasma: chemical hydrolysis and role of plasma esterases

It was shown previously that the anticancerous cytotoxic oxygenated triterpenes, cucurbitacin E (Cuc E) and its deacetylated form, cucurbitacin I (Cuc I), interacted differently with human serum albumin.

Report on the Medicinal Use of Eleven Lamiaceae Species in Lebanon and Rationalization of Their Antimicrobial Potential by Examination of the Chemical Composition and Antimicrobial Activity of Their Essential Oils

Many Lamiaceae species are consumed in the Lebanese cuisine as food or condiment and are largely used in the traditional medicine of Lebanon to treat various diseases, including microbial infections. In this article we report the traditional medicinal uses of eleven Lamiaceae species: Coridothymus capitatus L., Lavandula stoechas L., Lavandula angustifolia Mill., Mentha spicata L. subsp. condensata, Origanum syriacum L., Rosmarinus officinalis, Salvia fruticosa Miller., Satureja cuneifolia Ten., Satureja thymbra L., Thymbra spicata L., and Vitex agnus-castus L. and study the chemical composition and antimicrobial activity of their essential oils (EOs). Our survey showed that Lamiaceae species are mainly used against gastrointestinal disorders and microbial infections. Chemical analysis of the EOs obtained from these plants allowed us to identify seventy-five compounds describing more than 90% of the relative composition of each EO. Essential oils with high amounts of thymol and carvacrol possessed the strongest antimicrobial activity. As expected, these two compounds demonstrated an interesting antifungal efficacy against the filamentous fungus T. rubrum. Our results confirmed that some of the Lamiaceae species used in Lebanon ethnopharmacological practices as antimicrobial agents do possess antibacterial and antifungal potential consistent with their use in alternative or complementary medicine.

Chemical Composition and Antimicrobial Activity of the Essential Oil of Ruta chalepensis L. Growing Wild in Lebanon

The essential oils (EOs) isolated from the fresh aerial parts of Ruta chalepensis L. collected in North Lebanon were obtained by solvent‐free microwave extraction (Milestone®), yielding 0.12% EO from both the leaves and a mixture of stems and leaves. The EOs were characterized by GC/MS analysis, and 27 components were identified, which were primarily ketones (88.0–93.2%). The main components were nonan‐2‐one and undecan‐2‐one. The antimicrobial activity of the EOs against a Gram‐positive and a Gram‐negative bacterium, a yeast, and a dermatophyte was evaluated using the broth‐microdilution technique and expressed as minimal inhibitory concentration (MIC). The EOs revealed moderate in vitro antifungal activity against Trichophyton rubrum and Candida albicans.

Phenolic Compounds from Diluted Acid Hydrolysates of Olive Stones: Effect of Overliming

Annually, important quantities of olive residue are produced and may be the source of ecological damages. Like agricultural residues, which are abundant, renewable, low cost raw materials, olive stones are mainly subjected to biotechnological or chemical modifications in order to be transformed into valuable products (biofuels, biofertilizers, animal feed and chemical feed-stock). In aim to valorize olive stones, we are trying to identify the presence of different phenolic compounds in their dilute-acid hydrolysate (DAH). Phenolic compounds (PC) are considered as toxic material for fermentation process, therefore, their behavior are studied under overliming treatment with distinct pH levels (10 and 12), temperature (25 and 60°C) and detoxification time (15,30 and 60 min). Identification and quantification of phenolic compounds were performed by two chromatographic methods: Gas Chromatography mass spectrometry (GC-MS) and High-Performance Liquid Chromatography (HPLC). A liquid-liquid microextraction procedure is used in conjunction with silylation prior to the analysis of the compounds by GC-MS. Derivatives of benzoic acid, cinnamic acid, simple phenols, and aldehydes were identified. For all treatments combinations, pH 12 was more effective in reducing the total amount of phenolic compounds. Treatment of the hydrolysate with alkali at pH 12, 60°C and 60 min resulted in up to 29% decrease in the concentration of total phenolic compounds. Tyrosol, which was the main phenolic compound decreased by 73% under the same treatment. Chromatographic methods contributed to an accurate quantification and better understanding of the behavior of each PC, solely.

Disruption of biofilms from sewage pipes under physical and chemical conditioning

Biofilms grown inside two sewage collecting pipes located in industrial and residential areas are studied. Bacterial biomass inside three layers of biofilms was evaluated. Biofilm cohesion under different mixing rate and ionic strength was also investigated. Effects of physical and chemical parameters in the biofilms were evaluated by monitoring turbidity, chemical and biochemical oxygen demands. Extracted organic matter from biofilms was partitioned to polar, aromatic and saturated fractions using activated silica column chromatography. Results revealed that bacterial biomass growth depending on biofilm thickness and stratification. The most loaded stratum in bacterial biomass was the sewage-biofilm interface stratum that represented 51% of the total bacterial biomass. Stirring rate and ionic strength of mono- and bivalent salts showed a major influence in biofilm disruption. The stirring time enhanced the exchange dynamic and matter capture between biofilm fragments at the critical stirring rate 90 r/min. Sodium chloride showed the dispersing effect on biofilms in suspension, and decreased the BOD5 (biochemical oxygen demand) beyond the physiological salt concentration.

Chemical Diversity and Antimicrobial Activity of Salvia multicaulis Vahl Essential Oils.

The chemical compositions and antimicrobial activities of the essential oils (EOs) of aerial parts of Salvia multicaulis Vahl, collected during the same week from two different Lebanese regions, were investigated. The EOs were obtained by hydrodistillation using a Clevenger‐type apparatus and characterized by GC and GC/MS analyses. The minimum inhibitory concentrations of these EOs were determined against one Gram‐negative and two Gram‐positive bacteria, one yeast, and five dermatophytes using the broth microdilution technique. One EO was notably active against Staphylococcus aureus, methicillin‐resistant S. aureus, and all of the Trichophyton species tested. Nerolidol was found to be the major compound in the active oil; nerolidol was also absent from the inactive oil. This study demonstrated that nerolidol shows antimicrobial activity and therefore significantly contributes to the antimicrobial potential of the oil. The chemical diversity of worldwide S. multicaulis EOs was analyzed, revealing that the EOs of this study belong to two different chemotypes found in the literature. The nerolidol chemotype appears to be restricted to Lebanon, and it can be used as antimicrobial agent against external bacterial and fungal infections.

Capparis spinosa L. in A Systematic Review: A Xerophilous Species of Multi Values and Promising Potentialities for Agrosystems under the Threat of Global Warming

Caper (Capparis spinosa L.) is a xerophytic shrub with a remarkable adaptability to harsh environments. This plant species is of great interest for its medicinal/pharmacological properties and its culinary uses. Its phytochemical importance relies on many bioactive components present in different organs and its cultivation can be of considerable economic value. Moreover, taxonomic identification of C. spinosa L. has been difficult due to its wide heterogeneity, and many authors fell into confusion due to the scarcity of genetic studies. The present review summarizes information concerning C. spinosa L. including agronomic performance, botanical description, taxonomical approaches, traditional pharmacological uses, phytochemical evaluation and genetic studies. This knowledge represents an important tool for further research studies and agronomic development on this indigenous species with respect to the emerging climatic change in the Eastern Mediterranean countries. Indeed, this world region is particularly under the threat of global warming and it appears necessary to rethink agricultural systems to adapt them to current and futures challenging environmental conditions. Capparis spinosa L. could be a part of this approach. So, this review presents a state of the art considering caper as a potential interesting crop under arid or semi-arid regions (such as Eastern Mediterranean countries) within the climate change context. The aim is to raise awareness in the scientific community (geneticists, physiologists, ecophysiologists, agronomists, …) about the caper strengths and interest to the development of this shrub as a crop.