IN VITRO EVALUATION OF BIOLOGICAL ACTIVITIES OF PISTACIA LENTISCUS AQUEOUS EXTRACT

Objective: The aim of this study was to study the antioxidant potential and the antibacterial activity of leaves aqueous extract of Pistacia Lentiscus as well as the protective effect of this extract against the haemolysis in hypotonic condition, in oxidative stress and in the existence of saponin injury.Methods: We studied the antioxidant capacity through the DPPH assay, H2O2 scavenging activity, Ferric-reducing power (FRAP) assay, total antioxidant assay and the antibacterial activity using the disc diffusion method. We also investigated the haemolytic activity with the spectrophotometric method.Results: The result showed that the aqueous extract had a good antioxidant capacity, which was calculated as IC50. IC50 of the aqueous extract was found to be 9.89±0.7µg/ml for DPPH scavenging, 200±18.02µg/ml for H2O2 scavenging assay, 54.06±12.66µg/ml for Ferric-reducing power (FRAP) and 500±22.3 µg/ml for total antioxidant capacity. The aqueous extract also inhibited the growth of the tested bacterial strains with a maximum inhibition zone of 30.33±5.5 mm observed on Pseudomonas aeruginosa for wood-seed and a moderate activity against all other strain. The haemolytic analysis showed that the aqueous extract is not toxic for the human erythrocytes and protects them against the oxidative and osmotic stress and also against saponin injury.Conclusion: The results of our study suggest that the aqueous extract of leaves of Pistacia lentiscus possess potent anti-haemolytic activity, are a good source of natural antioxidant.Â

Resistance of Telluric Fungi to Chemical Fungicides

Our work focuses on the identification of resistance of telluric fungi to commonly used fungicidesin chemical control. We investigate the resistance of telluric fungi (Fusarium sp., Chalara sp., Sporonema sp., Stiebum sp., Didymabotrium sp., Dothichiza sp. and Sclerotopsis sp.) from cereal fields to four fungicides (Propicone, Vapcotop, Curitine V and Kazir). This study was based on direct contact of the telluric isolates with fungicides on Petri dishes. For the four tested fungicides different rates of resistance and susceptibility were observed according to the isolate and the used concentration. One of the isolates showed a high resistance to Vapcotop with 500 mg%252Fl. Generally the statistical analysis revealed that there are no significant differences in the effect of fungicides concentrations against isolates, while significant differences are observed between isolates

Chemical composition and antibacterial activity of Algerian propolis against fish pathogenic bacteria

Five different varieties of propolis from four sites from Sétif region (East of Algeria) (Babor, Setif; Ain-Abbassa and El-Hamma), and one site from the center of Algeria (Tizi-Ouzou) were chemically analysed by gas chromatography-mass spectrometry. One hundred and two compounds were identified including aromatic acids, linear hydrocarbons and their acids, terpenes and alcaloïdes. Furthermore, the in vitro bacteriostatic and bactericidal activities of the aqueous extracts were evaluated against one Gram positive (Bacillus subtilis, used as probiotics in aquaculture) and two Gram negative (Vibrio anguillarum and Vibrio harveyi, pathogenic for fish) bacteria. The obtained results showed that all aqueous extracts of propolis inhibit the growth of B. Subtilis while the growth inhibition of fish pathogens was achieved when using higher propolis concentrations. These antibacterial properties would warrant further studies on the clinical applications of propolis in aquaculture field. Keywords: Bactericidal activity; Chemical characterization; Propolis; Vibrio

ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF PLANTAGO MAJOR

Objective: The purpose of this research is to evaluate the antioxidant and antibacterial properties of different leaf extracts of Plantago major, using in vitro methods.Methods: The antimicrobial activity of different extracts (petroleum ether, ethyl acetate and aqueous fractions) from Plantago major leaves and their synergistic effect with standard antibiotic (Gentamicin) were evaluated using the disc diffusion method. The total phenolic and total flavonoid content of these extracts was determined according to the Folin-Ciocalteu procedure and Aluminum chloride colorimetric assay respectively. Antioxidant properties were determined via the DPPH free radical scavenging, β-carotene bleaching assay and ferrous ion chelating activity.Results: The total phenols and total flavonoid content of the extracts ranged from 5.79 to 114.45 mg GAE/g dry extract and from 1.24 to 5.48 µg QAE/mg dry extract respectively. The ethyl acetate fraction showed the highest DPPH scavenging capacity (IC50 = 12.85±0.27 µg/ml) and relative antioxidant activity of 70.48% in the β-carotene bleaching assay. While, aqueous and petroleum ether fractions have the lowest activities. On the other hand, only the aqueous fraction has a capacity of chelating iron (IC50 = 1.02±0.02 mg/ml). The findings indicated also that an ethyl acetate fraction was the most active in vitro against Gram-negative and Gram-positive bacteria strains. High inhibition zone of 16.7±1 mm and 14.3±0.6 was exhibited on Staphylococcus aureus and Bacillus cereus. Moderate one of 13.3±0.6 and 11.3±0.6 mm was obtained against Pseudomonas aeroginosa and Acinetobacter bowie. However, lowest antibacterial activity was obtained against Klebsiella pneumonia, Proteus mirabilis and Salmonella typhimurium. Furthermore, synergistic antibacterial activity was either obtained by the combination of standard antibiotic (Gentamicin) with the tested extracts.Conclusion: Our results showed a potent antioxidant and antibacterial activities of this species. This plant could be exploited as a potential source of natural antioxidant and antimicrobial agents for dreadful human diseases and oxidation prevention.Â

Chemical constituents of Helichrysum italicum (Roth) G. Don essential oil and their antimicrobial activity against Gram-positive and Gram-negative bacteria, filamentous fungi and Candida albicans

The aerial parts of Helichrysum italicum (Roth) G. Don were subjected to hydrodistillation to obtain essential oils which had been analyzed by gas chromatography and gas chromatography coupled with mass spectrometry and tested for antimicrobial activity against 12 bacteria, two yeasts and four fungi by agar diffusion method. The essential oil yielded 0.44% (v/w) and 67 compounds accounting for 99.24% of the oil were identified with a high content of oxygenated sesquiterpenes (61.42%). The most oxygenated sesquiterpene compounds were α-Cedrene (13.61%), α-Curcumene (11.41%), Geranyl acetate (10.05%), Limonene (6.07%), Nerol (5.04%), Neryl acetate (4.91%) and α-Pinene (3.78%). The antimicrobial activity of the essential oil was assayed by using the disk diffusion method on Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Micrococcus luteus ATCC 4698, Klebsiella pneumonia ATCC 4352, Enterococcus cereus ATCC 2035, Bacillus cereus ATCC 10876, Staphylococcus epidermidis ATCC 12228, Bacillus subtilis ATCC 9372, Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 49452, Proteus mirabilis ATCC 35659, Listeria monocytogenes ATCC 15313 and yeasts Candida albicans ATCC 10231, Saccharomyces cerevisiae ATCC 9763 and fungi, Fusarium solani var. coeruleum, Aspergillus niger, Alternaria alternata, Ascochyta rabiei. H. italicum inhibited the growth of all the tested microorganisms except three bacteria, E. coli ATCC 25922, K. pneumonia ATCC 4352 and L. monocytogenes ATCC 15313. The most sensitive bacterium was E. cereus ATCC 2035 with minimum inhibitory and bactericidal concentrations of 0.79 μg ml−1. A minimum fungistatic and fungicide concentration of 6.325 μg ml−1 and 12.65 μg ml−1 respectively was obtained with C. albicans ATCC 10231 and S. cerevisiae ATCC 9763. However the four fungi were more resistant with fungistatic minimum concentration ranging from 6.325 μg ml−1 to 50.6 μg ml−1 and a fungicide minimum concentration of 50.6 μg ml−1. This antimicrobial activity could be attributed to the essential oil chemical composition. Thus this study represents a first step in the study of the chemical composition of H. italicum (Roth) G. Don collected from north Algeria and its antimicrobial properties