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14 páginas.- 4 figuras.- 8 tablas.- 60 referencias, Background: Marine actinobacteria are a potential resource for natural products; their secondary bioactive metabolites have shown several biological activities. Most of the isolated and identified actinobacteria in Algeria were usually explored from caves, Saharan soil or palm groves. The marine ecosystem is poorly explored and documented. Methods: Five Streptomyces strains producing bioactive compounds were isolated from Rachgoun Island located in Western Algeria and characterised phenotypically and genotypically using microbiological and 16S rRNA sequencing methods, respectively. The crude extract of the most representative strain ¿Streptomyces sp. strain SM2.4¿ and its seven active fractions were characterised by GC/MS analysis. Results: Streptomyces sp. strain SM2.4 revealed the strongest activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, the fungus Aspergillus niger and was inactive against Gram-negative bacteria. GC/MS analysis of the methylated crude extract of Streptomyces sp. strain SM2.4 revealed the presence of 11 major compounds including fatty acids methyl ester (12-methyltridecanoic acid methyl ester, 9-hexadecenoic acid methyl ester, hexadecanoic acid methyl ester, 14-methylhexadecanoic acid methyl ester and 16-methylheptadecanoic acid methyl ester), 2,4-di-tert-butylphenol, (4S,4aS,8aR)-4,8a-dimethyloctahydro-4a(2H)-naphthalenol (geosmin), 2,4-dimethylbenzaldehyde, 3,4-difluorobenzaldehyde, dimethylfuran-2,4-dicarboxylate and pyrrolo(1,2-a)pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)-. Partial purification of the crude extract by Thin-layer chromatography provided seven active fractions which were tested by radial diffusion assay. GC/MS analysis of the active TLC-fractions revealed the presence of a mixture of active compounds from which 2-(bromomethyl)-2-(2-methylphenyl)-1,3-dioxolane was found to be a new 1,3 dioxolane derivative. Furthermore, 3,4-dimethylbenzamide and pyrido[2,3-d] pyridazine-1,4-dione, hexahydro-3-(2-methylpropyl)-, were extracted for the first time from a natural source. Conclusion: Our study reveals that marine Streptomyces sp. strain SM2.4 has an interesting antimicrobial potential due to its panel of bioactive compounds.

Background The constant development of microbial resistance to the traditional antimicrobial agents and the emergence of new infectious diseases justify the urgent need for new effective antimicrobial molecules. However, the irrational use of antibiotics increases microbial resistance dramatically and along with that the frequency of mortality associated with infections is higher. Therefore, to combat the antimicrobial resistance, the screening of compounds with novel chemical structures is essential. This study intended to determine the antimicrobial potential of Streptomyces GLD22 strain isolated from Algeria. Methods The characterization of Streptomyces strain GLD22 was performed by physiological, biochemical and molecular tests. The antimicrobial activity was tested by the well diffusion method and the minimum inhibitory concentration value calculation were performed using broth micro dilution technique. The extracellular metabolites profiling was done using GC–MS. Results Physiological, biochemical and phylogenetic analysis confirmed that the strain GLD22 showed maximum identity towards Streptomyces species. The extra cellular metabolites revealed their antimicrobial activity at 1 mg/ml for Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, whereas Staphylococcus aureus, Bacillus cereus and Bacillus subtilis documented 0.5, 1 and 1 mg/ml respectively. GC–MS analysis confirmed that 2-tert-butyl-4,6-bis(3,5-di-tert-butyl-4-hydroxybenzyl) phenol, Dibutyl phthalate and Cyclo(leucyloprolyl) were the major drug molecules present in the extract. Conclusion The novel Streptomyces strain GLD22 recovered from the Gueldaman cave of Algeria showed better antimicrobial activity towards both Gram positive and Gram negative pathogens. Interestingly, the MIC values were comparable with the standard drug molecules. In addition, the identification of active metabolites present in the crude extracts was an advantage.

Antimicrobial activity of hydroalcoholic extracts (30/70) from leaves and stems of three halophytes (Tamarix africana, Arthrocnemum macrostachyum and Suaeda fruticose) was investigated. In vivo toxicological study and anti-inflammatory activity of leaf extract of T. africana were tested on carrageenan-induced inflammatory paw edema. T. africana possessed significant anti-inflammatory activity at 150 and 300 mg/kg confirmed by histological study of inflamed tissues. Six phenolic acids and 10 flavonoids where identified by HPLC–DAD. Gallic acid, Rutin and Kaempferol-3-O-glucoside were the major compounds. For the antibiotic assays, S. fruticosa leaf extract exhibited strong bactericidal power against S. aureus with MBC of 1.25 mg/mL whereas T. africana leaf and stem samples exhibited a significant bactericidal activity against S. aureus and B. subtilis compared to the negative control (Ampicillin and Chloramphenicol). Crude leaf and stem extracts from T. africana and stem extract from S. fruticosa exhibited a strong antifungal effect against C. albicans.

11 páginas.-- 2 figuras.-- 6 tablas.-- 65 referencias, The discovery of new antibiotics and other bioactive microbial metabolites is a priority given the frequency of the emerging multi-drug resistant pathogenic microorganisms. Thus, scientists are searching for new antibiotics in microorganisms isolated from extreme habitats such as caves. In the present study, we aimed to perform the first analysis on culturable microorganisms in the Chaabe Cave (Algeria), and to test the antimicrobial activities of the isolates (Streptomyces spp. and Penicillium spp.). The potential for antimicrobial activity of 47 strains of actinomycetes and 23 strains of fungi were tested on Candida albicans, Staphylococcus aureus, Micrococcus luteus, Listeria monocytogenes, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. The identification of the most active actinomycetes strains by 16S rRNA gene sequence analysis revealed that these isolates were exclusively affiliated to the genus Streptomyces. On the other hand, the fungi were determined by phylogenetic analysis based on the ITS region or on the β tubulin gene and were affiliated to the genera Readeriella, Cladosporium, Aspergillus, Penicillium, Beauveria, Alternaria, Rhizopus, and Rhizomucor. The strains showed strong inhibitory activity against pathogenic microorganisms and the diameters of the inhibition zones vary between 7.5 and 34 mm for Streptomyces strains, and between 6.5 and 19.50 mm for Penicillium strains. The data indicated that the majority (72.86%) of the 70 isolates were active against at least one of the tested microorganisms. The production of nonpolyenic antifungal substances by active Streptomyces isolates was investigated using several criteria (antibacterial activity, ergosterol inhibition, and UV-visible spectra) of active extracts. The results were promising and showed that the metabolites produced by the actinomycete strains do not have a UV-visible spectrum characteristic of a polyenic structure. The Chaabe Cave possesses a diversity of microorganisms that could lead to new antibiotics necessary in the fight against drug-resistant pathogens and warrant further study

The current study was carried out to investigate the chemical composition of Pistacia lentiscus fruit fatty oil by HPLC–DAD and GC analysis. The quantification of phenolic content and DPPH radical scavenging capacity of this oil were furthermore evaluated. The results showed that the oil has the highest phenolic content (810 mg GAE/kg oil). The capacity to scavenge DPPH radical was admissible (EC50 = 20.619 ± 0.312 mg/mL), compared to the butylated hydroxyanisole (BHA) (0.012 ± 0.0001 mg/mL). The main fatty acids where oleic, palmitic, linoleic, palmitoleic and stearic acids which have specific carbon number and their values in percentage are C18:1 n-9 (50.02 ± 0.55%), C16:0 (24.83 ± 1.25%), C18:2 n-6 (17.24 ± 0.10%), C16:1 n-7(1.55 ± 0.09%) and C18:0 (1.08 ± 0.02%), respectively. The analyses showed concentrations of approximately 26% of saturated fatty acids, 52% of monounsaturated and 18% of polyunsaturated.

Extracts and fractions using six solvents of increasing polarities from Northwest Algeria (Tamarix africana, Arthrocnemum macrostachyum and Suaeda fruticosa) were studied for phytochemical analysis...

The aim of the current study is to analyze the phytochemical, antioxidant and antimicrobial activities of 34 extracts prepared from Pistacia atlantica Desf. subsp. atlantica, according to gender, organ type (roots, buds and fruits), geographical location and stage of ripening. Bud extracts exhibited the highest phenolic content (565.74 ± 9.84 mg GAE/g DM), followed by fruit and root extracts. TFC and TTC ranged from 0.38 ± 0.03 to 1.92 ± 0.11 mg CE/g DM and from 0.37 ± 0.03 to 16.54 ± 0.94 mg CE/g DM, respectively. For DPPH and TAC assays, the values varied from 0.038 ± 0.000 to 1.331 ± 0.114 mg/mL and 1.58 ± 0.06 to 43.64 ± 2.58 mg AAE/g DM, respectively. Besides, bud extracts showed the highest bioactivity against pathogenic bacteria and a slight antifungal effect. Additionally, HPLC-DAD analysis revealed that the caffeic acid and the dimethyl-allyl caffeic acid characterized the bud extract, while the rutin and the hydroxytyrosol were abundant in the red fruit extract. The present evidence suggests that P. atlantica may be considered as a potential source of new additives for therapeutic, food and cosmetic products.

The chemical composition of 93 oil samples from the aerial parts of Pituranthos scoparius, harvested in three regions of Algeria, was investigated by GC-FID, GC/MS and 13 C-NMR. Monoterpene hydrocarbons dominated in association with phenylpropanoids and a chemical variability was found highlighting three clusters. The composition of group I (36 samples) exhibited an atypical composition characterized by a very high contents of 6-methoxyelemicine (13.0 - 59.6%), followed by sabinene (1.1 - 43.0%) and limonene (6.6 - 39.0%), while the samples of group II (12 samples) contained a high content of limonene (9.2 - 44.0%), followed by myristicine (0.0 - 29.4%) and a lower amount of sabinene (0.8 - 2.3%). Group III (45 samples) could be divided in two subgroups. Subgroup SGIIIA was characterized by a very high content of sabinene (28.0 - 55.6%), followed by elemicine (0.0 - 29.1%), while the samples belonging to SGIIIB were characterized by the lower content of sabinene (6.2 - 35.5%) and a significant content of myristicine (1.5 - 32.4%), α-pinene (4.2 - 31.0%) and dill apiole (0.1 - 31.4%). Each harvested region was characterized by a different chemical composition.

The aim of this study is to evaluate the in vitro effects of aqueous extracts of three species of Algerian desert truffles (Terfezia claveryi, T. leonis, and Tirmania nivea) on the growth of Pseudomonas aeruginosa and Staphylococcus aureus. The antimicrobial activity of the three aqueous extracts was tested using the agar well diffusion and kinetic bacterial growth curves methods. The aqueous extracts of Terfezia claveryi and Tirmania nivea were found to possess a very powerful antibacterial activity against both S. aureus and P. aeruginosa using agar well diffusion. Using 4% and 11% of the aqueous extracts of T. claveryi and T. nivea in the growth medium of S. aureus caused a significant inhibition of S. aureus growth by 86.48% and 99.09%, respectively. The aqueous extracts of T. claveryi and T. nivea were found to cause a significant inhibition of the growth of P. aeruginosa by 71.11% and 100%, respectively. However, the aqueous extract of Terfecia leonis did not show any antibacterial activity. Therefore, T. claveryi and Tirmania nivea can be considered a source of natural therapeutic agents that can be used to treat eye infections caused by resistant bacteria such as P. aeruginosa and S. aureus.