Évaluation de l’activité inhibitrice des extraits d'une algue brune, Padina pavonica, récoltée sur les côtes libanaises

Le criblage de l’activité antibactérienne in vitro des extraits de Padina pavonica, récoltée sur les côtes méditerranéenne d’El Mina-Tripoli, Liban, a été effectué sur cinq souches cliniques des bactéries: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaricus et Enterococcus faecalis. L’activité antimicrobienne a été évaluée par la méthode de diffusion sur des disques de cellulose. Les résultats ont révélé que l’extrait total de Padina pavonica présente une activité importante contre Pseudomonas aeruginosa et Esherichia coli alors qu’aucune activité n’a été enregistré contre Klebsiella pneumoniae, Proteus vulgaricus et Enterococcus faecalis. Sur les trois extraits de l’algue préparés par extraction successive dans l’éther de pétrole, le chloroforme et le méthanol, l’extrait le plus actif contre klebsiella pneumoniae et Pseudomonas aeruginosa a été celui obtenu avec l’éther de pétrole. Les extraits obtenus dans le chloroforme et le méthanol n’ont montré aucune activité contre les souches étudiées.Mots-clés : algue brune, Padina pavonica, activité antibactérienne, côte méditerranéenne libanaise

Screening of antibacterial and antifungal activities in green and brown algae from the coast of Sidi Bouzid (El Jadida, Morocco)

Six organic extracts prepared with different solvents (methanol, acetone, hexane, chloroform and dichloromethane-methanol) and aqueous extract of 27 species of marine algae belonging to the Chlorophyta and Phaeophyta were studied for antibacterial and antifungal activities against pathogenic microorganism: eight Gram-positive bacteria: Bacillus cereus, Bacillus thuringiensis, Bacillus subtillus, Clostridium sporogenes, Staphylococcus aureus, Mycobacterium smegmatis, Streptococcus faecalis and Bacillus sp, two Gram-negative bacteria: Escherichia coli and Pseudomonas sp and against fungi: Candida tropicalis and Cryptococcus neoformans. The best activity was observed in methanolic extract followed by acetonic extract and that prepared with methanol–dichloromethane. Of the 27 species tested, those belonging to Phaeophyceae were the most active in comparison with Chlorophyceae. The Gram-positive bacteria presented a sensibility superior to the Gram-negative and S. aureus ssp. aureus was the more sensitiveKey words: Macroalgae, algal extracts, antibacterial activity, antifungal activity, pathogenic microorganism

INHIBITIVE ACTIVITY OF 17 MARINE ALGAE FROM THE COAST OF EL JADIDA-MOROCCO AGAINST ERWINIA CHRYSANTHEMI

Objective: The objective of our work was to search for a new biopesticides extracted from marine algae found on the coast of El Jadida, Sidi Bouzid-Morocco.Methods: Extracts of 17 species of algae (Rhodophyceae, Rhodophyceae, Chlorophyceae) collected from the coast of El Jadida, Morocco, were tested for their antibacterial activity against the bacterial strain Erwinia chrysanthemi that causes soft rot in potato (Solanum tuberosum L.).Results: Of the 17 species studied, those belonging to the Phaeophyceae and Rhodophyceae were the most active, while Chlorophyceae have a low inhibition. Maximum inhibition of the growth of Erwinia chrysanthemi was obtained by extracts prepared in dichloromethane and methanol, and by dichloromethane extract. No activity was observed in the aqueous extracts.Conclusion: The results obtained in this study clearly indicated that macroalgae from the coast of Sidi Bouzid can be used in the treatment of plant diseases especially soft rot of potato.Â

Fucus spiralis extract and fractions: Anticancer and pharmacological potentials

Purpose: Sea macroalgae are an important source of biologically highly valuable compounds. The main aim of this study was to investigate the in vitro anticancer properties and chemical composition of the dichloromethane-methanol extract and three fractions of the Fucus spiralis from coastline of Morocco. Methods: Fractions were made from dichloromethane: methanol (1:1) extract of Fucus spiralis: petroleum-ether, ethyl-acetate and n-butanol. Extract and fractions were screened for in vitro cytotoxicity by MTT assay against human cervical adenocarcinoma (HeLa), colorectal adenocarcinoma (LS-174T), lung carcinoma (A549), and normal human lung fibroblasts (MRC-5). Cell cycle distribution of the HeLa cells was evaluated using flow cytometry. Acridine orange (AO)-ethidium bromide (EB) staining was used to assess morphological changes of HeLa cells under fluorescence microscope. Anti-migration and anti-angiogenic properties were investigated using scratch and tube formation assays against human endothelium-derived permanent EA.hy926 cell line. Antidiabetic activity was tested using anti-α-glucosidase assay. Antimicrobial effect was tested using micro- dilution method. Results: Petroleum-ether fraction оf Fucus spiralis rich in fatty acids exerted the highest cytotoxicity against HeLa cells. Ethyl-acetate and petroleum-ether fractions induced the highest accumulation of the HeLa cells in sub-G1 and G2/M phases. Extract and fractions showed proapoptotic effect on HeLa cells under fluorescent microscope. They exhibited antimigratory and antiangiogenic effects in vitro. IC50 value for α-glucosidase inhibitory activity was much stronger than standard acarbose. n-Butanol fraction exerted the highest antibacterial and antifungal activity. Conclusions: The investigation of various biological activities of the extract and fractions obtained from Fucus spiralis may suggest a promising anticancer and pharmacological potential of this edible macroalga

Antiviral Activities of Sulfated Polysaccharides Isolated from Sphaerococcus coronopifolius (Rhodophytha, Gigartinales) and Boergeseniella thuyoides (Rhodophyta, Ceramiales)

Water-soluble sulfated polysaccharides isolated from two red algae Sphaerococcus coronopifolius (Gigartinales, Sphaerococcaceae) and Boergeseniella thuyoides (Ceramiales, Rhodomelaceae) collected on the coast of Morocco inhibited in vitro replication of the Human Immunodeficiency Virus (HIV) at 12.5 μg/mL. In addition, polysaccharides were capable of inhibiting the in vitro replication of Herpes simplex virus type 1 (HSV-1) on Vero cells values of EC50 of 4.1 and 17.2 μg/mL, respectively. The adsorption step of HSV-1 to the host cell seems to be the specific target for polysaccharide action. While for HIV-1, these results suggest a direct inhibitory effect on HIV-1 replication by controlling the appearance of the new generations of virus and potential virucidal effect. The polysaccharides from S. coronopifolius (PSC) and B. thuyoides (PBT) were composed of galactose, 3,6-anhydrogalactose, uronics acids, sulfate in ratios of 33.1, 11.0, 7.7 and 24.0% (w/w) and 25.4, 16.0, 3.2, 7.6% (w/w), respectively

ANTIMICROBIAL PROPERTIES OF SEVEN BROWN ALGAE HARVESTED FROM THE COAST OF SIDI BOUZID (EL JADIDA-MOROCCO)

Objective: This work aims at the screening of the antimicrobial activity of the seven brown marine algae of theCoast of Sidi Bouzid (El Jadida-Morocco). Methods: The aim of this study was to evaluate the antimicrobial activity of seven brown marine algae against three Gram-positive bacteria (Staphylococcus epidermidis, Staphylococcus aureus and Streptococcus pyogenes). Three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia) and two fungi (Aspergillus Niger and Candida tropicalis). Thus, 35 algal extracts were prepared with five organic solvents methanol/water, methanol, dichloromethane/methanol, dichloromethane and ethyl acetate. The antibacterial activity was evaluated through the disk diffusion method. Results: Data revealed that the Staphylococcus aureus bacteria was the most sensitive pathogen by showing the highest zone of inhibitions of 20 mm with the lowest Minimum Inhibitory Concentration (MIC) of 2 μgmL⁻¹ methanol/water extract of Cystoseira tamariscifolia. Whereas, antifungal activity, the highest zone of inhibitions of 21 mm and 22 mm with the lowest Minimum Inhibitory Concentration (MIC) of 5 μgmL-¹ was respectively shown in the methanol/water extract of Laminaria ochroleuca against Candida tropicalis and in the dichloromethanolic extract of Sargassum vulgare against Aspergillus niger. Conclusion: The results indicate that these algal extracts can further be analyzed and purified for relevant antibacterial and antifungal compounds which can be used in therapeutics and other applications