Marc El Beyrouthy

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.

Essential Oil from Berries of Lebanese Juniperus excelsa M. Bieb Displays Similar Antibacterial Activity to Chlorhexidine but Higher Cytocompatibility with Human Oral Primary Cells

Chlorhexidine (CHX), one of the most effective drugs administered for periodontal treatment, presents collateral effects including toxicity when used for prolonged periods; here, we have evaluated the bactericidal potency and the cytocompatibility of Juniperus excelsa M. Bieb essential oil (EO) in comparison with 0.05% CHX. The EO was extracted from berries by hydrodistillation and components identified by gas chromatography and mass spectrometry. Bacterial inhibition halo analysis, quantitative cell viability 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenyl amino) carbonyl]-2H-tetrazolium hydroxide assay (XTT), and colony forming unit (CFU) count were evaluated against the two biofilm formers Aggregatibacter actinomycetemcomitans and Streptococcus mutans. Finally, cytocompatibility was assessed with human primary gingival fibroblasts (HGF) and mucosal keratinocytes (HK). The resulting EO was mainly composed of monoterpene hydrocarbons and oxygenated monoterpenes. An inhibition halo test demonstrated that both bacteria were sensitive to the EO; XTT analysis and CFU counts confirmed that 10-fold-diluted EO determined a statistically significant (p < 0.05) reduction in bacteria count and viability towards both biofilm and planktonic forms in a comparable manner to those obtained with CHX. Moreover, EO displayed higher cytocompatibility than CHX (p < 0.05). In conclusion, EO exhibited bactericidal activity similar to CHX, but a superior cytocompatibility, making it a promising antiseptic alternative to CHX.

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.

Contribution à l'ethnopharmacologie libanaise et aux Lamiaceae du Liban

Au Moyen-orient, les plantes médicinales se raréfient car leur habitat naturel est de plus en plus réduit et pollué, tandis que le savoir des tradipraticiens, non écrit, tend à disparaître : telles sont les principales conclusions, très alarmantes, d’une synthèse d’articles parue dans la dernière livraison de l’ecAM, publication internationale scientifique consacrée aux médecines alternatives (Azaizeh et al., 2006). Le texte souligne en outre le contraste entre le riche passé médical du monde arabe, où l’on avait repris en partie le savoir d’Hippocrate, mais aussi délimité les rôles du thérapeute (futur médecin) et de l’herboriste (futur pharmacien), avec la méconnaissance de ce patrimoine par les praticiens actuels. Les mêmes auteurs ont aussi constaté que les tradipraticiens arabes sont de moins en moins nombreux et leur savoir, transmis de génération en génération, est très variable. Si la concurrence entre eux peut être rude, ils communiquent peu avec leurs confrères et sont réticents à constituer des syndicats ainsi qu’à collaborer avec des médecins. Dans les pays où la transmission des connaissances est basée sur l’oralité, il est urgent de conserver une trace écrite des médecines traditionnelles au sein de pharmacopées. Les savoirs traditionnels et les plantes auxquelles ils se réfèrent s’éteignent en effet progressivement. Acta Bot. Gallica, 156 (3), 515-521, 2009.

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.

Variation in the essential oils of Thymbra spicata L. growing wild in Lebanon according to the date of harvest

Thymbra spicata, an aromatic shrub belonging to Lamiaceae family and growing wild in Lebanon, was collected from Nahr Ibrahim in ten different harvest dates (from 11 October 2011 until 11 May 2012) and the composition of the essential oils (EOs) of air-dried aerial parts extracted by Clevenger-type hydrodistillation was determined by gas chromatography coupled with mass spectrometry (GC–MS). The amount and nature of the chemical compounds varied considerably from one sample to another depending on the harvest date. Oxygenated monoterpenes showed majority over monoterpene hydrocarbons only during the flowering stage (in May). In general, twenty-seven compounds of the EOs, which made up 89.4–98.7%, were identified in the oil of Thymbra spicata and the yield ranged between 3.5% and 6.6%. The main components were: carvacrol (16.1–62.9%), α-thujene (1.7–4.8%), myrcene (1.1–5.1%), γ-terpinene (11.4–24.1%) and p-cymene (8.1–46.8%).

Chemical Composition and Antimicrobial Activity of Origanum libanoticum, Origanum ehrenbergii and Origanum syriacum Growing Wild in Lebanon

The essential oils (EOs) of the aerial parts of Origanum libanoticum and Origanum ehrenbergii, endemic to Lebanon, and Origanum syriacum, endemic to the Levantine, were obtained by distillation with a Clevenger apparatus. GC and GC/MS allowed identification of 96.4%, 93.5%, and 95.2% of their constituents, respectively. Carvacrol was the major component of both O. syriacum EO (79%) and O. ehrenbergii EO (60.8%). This compound was absent in O. libanoticum EO and the major compounds were β‐caryophyllene (26.8%), caryophyllene oxide (22.6%), and germacrene D (17.2%). The assessment of their antimicrobial activity against Candida albicans and six pathogenic bacteria revealed that O. libanoticum EO was inactive, while O. syriacum and O. ehrenbergii showed moderate antimicrobial activity with minimal inhibitory concentrations varying from 400 to 1200 μg/ml. These results support the traditional use of these last two species in traditional herbal preparations in Lebanon.

Essential oil composition of Rosa damascena Mill. from different localities in Lebanon

Abstract Rosa damascena Mill. is used for essential oil production in many regions in the world. Surveys conducted in Lebanon showed that Lebanese people still widely use R. damascena in its multiple varieties to produce rose water. In this study seven cultivars of R. damascena growing in different ecosystems were collected from several regions in Lebanon. The oil has been extracted by steam distillation and analyzed by gas chromatography coupled to mass spectrometry GC/MS and gas chromatography equipped with a flame ionizing detector GC/FID. The investigated factors were cultural practices, taxonomical and ecological characters. We report the differences in the identified components. The study shows quantitative and qualitative differences between all samples and those of oils from other countries. This is the first report on the chemical composition of R. damascena growing in Lebanon.