Hussein Kanaan

Antibacterial and antibiofilm activities of polysaccharides, essential oil, and fatty oil extracted from Laurus nobilis growing in Lebanon.

OBJECTIVEnTo evaluate the antibacterial activity of the extracts of Laurus nobilis against three Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212 and Staphylococcus epidermidis CIP 444) and two Gram-negative bacteria (Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 27853). Also, the antibiofilm activity has been investigated against the biofilm produced by Staphylococcus epidermidis CIP 444.nnnMATERIALSnThe polysaccharides, essential oil, and fatty oils extracted from the plant were used in broth microdilution methods to study the minimal inhibitory concentration, and then the minimal bactericidal concentration was determined.nnnRESULTSnThe results showed that alginate, fucoidan, fatty oils and essential oil have good antibacterial activities against the 5 bacterial strains, and a negligible biofilm eradication activity of fucoidan, laminaran, fatty oil, and essential oil was observed, but a promising biofilm eradication activity was obtained with alginate, which showed a reduced biofilm mass even at low concentration.nnnCONCLUSIONSnThe extracts obtained have promising antibacterial capacities which need further investigation for them to be incorporated in medical or nutritional applications.

Polysaccharides of the red algae " Pterocladia" growing on the Lebanese coast: Isolation, structural features with antioxidant and anticoagulant activities

In addition to their high nutritional value, red algae are of great interest as a source of therapeutic substances. However, despite their abundance on the Lebanese coast red algae have never been studied before. Therefore, we attempted to study among the available biomass one of the species of red algae growing on the Lebanese coast “ Pterocladia ”. We performed the extraction of trace elements, fatty acids, sulfated galactans and watersoluble polysaccharides of the phycocolloids family (carrageenans) whose physicochemical gelling or stabilizing effects attract many industrial sectors. The analysis of trace elements sho ws large amounts of potassium, calcium, silicon and iron. Moreover, Pterocladia appears to be rich in saturated fatty acids (69%) with palmitic acid as major fatty acid and 31% of monounsaturated fatty acids. The extraction yields were 2.7% for sulfated ga lactans and 11.5% for carrageenan. In order to elucidate their structures, H¹ NMR spectroscopy was performed as well as Infra-Red spectroscopy which allowed us to reveal their functional groups. A study of the antioxidant effect by the electrolysis method showed a greater effect for sulfated galactans. Furthermore, the study of the anticoagulant effect by APTT test, activated partial thromboplastin time, showed more pronounced anticoagulant power of sulfated galactans. The results of the present study confirmed the potential use of the red algae Pterocladia as a source of active known molecules.

The antioxidant and anticoagulant activities of polysaccharides isolated from the brown algae Dictyopteris polypodioides growing on the Lebanese coast

Article history: In this study, we attempt to isolate the polysaccharides from the brown seaweed Dictyopteris polypodioides (Dp) growing on the Lebanese coast. The percentages of the main polysaccharide alginic acid were 4.6% in May and 6.25% in July. The extracted yields of Fucoidan, Laminaran and Mannuronan (FLM) and Mannuronan (M) alone were respectively 0.75% and 0.38% in May and 1.15% and 0.67% in July. We performed the infrared spectroscopy in order to reveal the functional groups of alginate and mannuronan. Moreover, a non-destructive technique ¹ H NMR was used to determine the structure of alginate and the distribution of guluronic (G) and mannuronic acid (M) in the chain, allowing us therefore to calculate the ratio M/G. The latter was 0.96 showing a strong ability of alginate to capture heavy metals. The analysis of trace elements showed great amounts of K, Si, Na and Mg in both seasons. Moreover, Dictyopteris appears to be rich in fatty acids (10 items) with palmitic and oleic acids as main fatty acids. Furthermore, the anticoagulant activity of polysaccharides was investigated by activated partial thromboplastin time (APTT) clotting assay and the antioxidant activity was studied by electrolysis method. It has been shown that the FLM and M fractions of Dictyopteris polypodioides have a significant antioxidant and anticoagulant activities. Further investigations are imperative in order to develop new molecules based on these polysaccharides to be used as drugs or for healthcare in general.

Diversity Investigation of the Seaweeds Growing on the Lebanese Coast

By specialized underwater cameras we have filmed and collected samples of algae from the following sites along the Lebanese coast: Batroun, Barbara, Manara, Officer’s Military club, Saida, Sarafand, Tyre and Naqoura. We have identified ninety-four species of algae that grow along the Lebanese coast and we have established a collection sites map of these algal species. The identification of the samples was done in three steps: (1) Determine the largest group (green, brown and red algae) to which the sample belongs, then continue searching within the most likely group. (2) Seek off in the succession of morphological types which proposed that the sample is approaching. (3) Seek out using the illustrations and descriptions a satisfactory identification. It is worth noting that confirmation cannot be obtained in all cases unless a careful reading of the description is done. (4) We then proceeded to the classification of the collected seaweeds which are distributed as follows: Rhodophyta forty one species, Ochrophyta ntwenty two species, Chlorophyta twenty six species and Cyanobacteria five species. (5) Synthesis: The present study allowed us to establish a primary infrastructure regarding the distribution of the Lebanese seaweeds. Such findings represent an important scientific support concerning the Mediterranean seaweeds, which provides a great assist in algal studies and all its applications. This screening of the Lebanese coastline shows a broad and significant algal distribution. The most common algal types among the identified ones are: Sargassum, Padina, Laurencia, Ulva, Corallina, Hypnea, Chondracanthus, Jania, Amphiroa, Pterocladia, Cladophera, Codium.

Variation of thymol, carvacrol and thymoquinone production from wild and cultivated Origanum syriacum of South Lebanon

Essential oils from wild and cultivatedxa0Origanum syriacumxa0were prepared monthly by hydrodistillation. Their composition in thymol, carvacrol and thymoquinone were studied byGas chromatography–mass spectrometry (GC-MS). Essential oils extraction ranged from 3.82 and 3.44% in February to 8.4 and 6.8% in may, from cultivated and wild samples respectively. The essential oil composition for all samples was dominated by carvacrol. The cultivated populations harvested in April just before flowering had a higher peak content in thymol (31.5%) and carvacrol (49.8%). Thymoquinone was detected in traces only in February, and was not found in any other population studied fromxa0O. syriacumxa0of South Lebanon. n n xa0 n n Key words:xa0Origanum syriacum, essential oil, carvacrol, thymol, thymoquinone.

Screening for antibacterial and antibiofilm activities in Astragalus angulosus

Aim: In a search for finding novel therapeutic agents, extracts from an endemic Lebanese plant, Astragalus angulosus, were evaluated for their potential in-vitro antibacterial and antibiofilm activities against three Gram-positive bacterial strains; Staphylococcus epidermidis (CIP444), Staphylococcus aureus (ATCC25923), and Enterococcus faecalis (ATCC29212); in addition to two Gram-negative strains, Escherichia coli (ATCC35218) and Pseudomonas aeruginosa (ATCC27853). Materials and Methods: The plant was collected in April of 2013 and divided into several different portions, then its extracts were obtained by maceration using two different solvents. Extract analysis followed directly where microtiter broth dilution method was employed to assess antibacterial activity, while antibiofilm potential was tested using colorimetric method. Results: Whole plant ethanolic extract showed the highest bacteriostatic effect at a concentration of 12.78 mg/ml and also was the most versatile exerting its effect against 3 different strains. Other extracts also exhibited an effect but at higher concentrations and each against a single strain. Regarding antibiofilm activity, the majority of the extracts were able to eradicate >50% of S. epidermidis preformed biofilm, where the highest activity was obtained with flower fraction extracted in water, achieving 67.7% biofilm eradication at 0.2 mg/ml. Conclusions: This plant possesses a promising potential in regard to eradicating bacteria and their biofilms and it is the first contributing step of establishing a library for the endemic Lebanese plants in this domain.