Isolation and characterization of rhizospheric Streptomyces spp. for the biocontrol of Fusarium wilt (bayoud) disease of date palm (Phoenix dactylifera L.)

Fusarium wilt of date palm (Phoenix dactylifera L.) caused by Fusarium oxysporum f.sp. Albedinis is one of the most destructive diseases in North Africa spicily in Algeria and Morocco. The objectives of this work were the isolation, identification and biocontrol efficacies testing of rhizospheric actinobacteria of medicinal plant Astragalus gombo against fusarium wilt disease in date palm. Five rhizospheric Streptomyces spp. Isolates bi02, bi21, bi24, bi26 and bi28 showed the largest zone of inhibition demonstrating a potent effect against F. oxysporum f.sp. Albedinis and a broad spectrum of antimicrobial activities against the test microorganisms. All these selected isolates produced indol acetic acid (IAA) at different levels, exhibited higher activity of phosphate solubilisation and siderophore production as well as chitinase and protease activities. The inoculation of infected date palm with the five Streptomyces spp. Increased all parameters of growth measured in controlled conditions. The study revealed that the five Streptomyces spp. could be a potential biocontrol agent for controlling palm and also promoting growth of plants

Antifungal Activity of Mentha Rotundifolia Essential Oil Against Fusarium Oxysporum

The antifungal activity of Mentha rotundifolia essential oil, harvested in Setif (Algeria) was evaluated in vitro against a phytopathogenic fungi Fusarium oxysporum, causing damage on tomato. The molecular identification of the strain was based on a comparison (BLAST) of the sequences obtained against a database and was often supplemented by microscopic observations. After quot%253BSANGERquot%253B sequencing of the PCR products, the sequences were received in FASTA format. Analysis of M. rotundifolia essential oil by Gas Chromatography%252FMass Spectrometry method (GC-MS) identified 14 compounds. The 3-Cyclopenten-1-one, 2-hydroxy-3- (3-methyl-2-butenyl) - was the major constituent of this oil with a rate of about 89.09%25. For this activity, we adopted the technique of direct contact on agar. F. oxysporum continued to grow on oil-free media at 1%25 and 0.1%25 (fungistatic effect)%253B also on media with an oil concentration of 0.01%25. While the explants taken from petri dish with essential oil concentration of 2%253B 4 and 10%25 did not grow (fungicidal effect). The very interesting antifungal effect of M. rotundifolia essential oil indicates the potential of this plant species as a source of natural fungicidal material. The present study revealed that this mint exhibited antifungal effect against F. oxysporum which provided a scientific basis for the use of this species as a good source of antifungal compounds. This preliminary work could provide a basis for the determination of sufficient and effective concentrations for in planta studies for the biological control of natural active substances of M. rotundifolia against fungal diseases

Antimicrobial and Antioxidant Activities of Flavonoids Extracted from Pistacia lentiscus L., Leaves

Increasingly, the flavonoids becoming the subject of biomedical researches, and many groups have isolated and identified the structures of flavonoids possessing important biological activities. This assess investigates the antimicrobial fight and the antioxidant strengths of flavonoids extracted from Pistacia lentiscus L. leaves.  The extract was first analyzed for its phenolic content, then the flavonoids were tested for their antimicrobial capacities by the method of diffusion against fourteen bacteria, two fungi and one yeast. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of flavonoids were determined using the dilution method on solid medium, however, the antioxidant activity was evaluated through the ability of the extract to scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals and the reducing power essay. The results indicate that flavonoids extract contain other phenolics groups. On the other side, the Antibacterial tests exhibited different activities depending on the strains. Unlike, the MIC and the MBC showed that the flavonoids extract showed a best activity against Candida albicans and Vibrio cholerae. Concerning antioxidant activity, the results indicate a moderate capacity of the flavonoid extract. These preliminary results may justify the use of this plant in the treatment of some diseases and may be exploited for therapeutic purposes. Keywords: Antimicrobial, Antioxidant, Pistacia lentiscus, flavonoids, MIC, MBC

Formulation of the endophytic fungus Cladosporium oxysporum Berk. & M.A. Curtis, isolated from Euphorbia bupleuroides subsp. luteola, as a new biocontrol tool against the black bean aphid (Aphis fabae Scop.)

Two formulations containing culture filtrates and conidial suspensions of the endophytic fungus Cladosporium oxysporum Berk. & M.A. Curtis, isolated previously from stems of Euphorbia bupleuroides subsp. luteola (Kralik) Maire, were experimentally tested for their aphicid activity against the black bean aphid Aphis fabae Scop. found in Algeria. It was shown that invert emulsions are more effective against aphids, than using aqueous suspensions. This was especially true for formulations containing culture filtrates. The relatively insignificant mortalities obtained by formulations containing conidial suspensions indicated a low infectious potential towards the aphids. The proteolytic activity seemed to be more important than the chitinolytic activity of the fungus against the black bean aphid A. fabae

Screening of Antimicrobial and Antioxidant Secondary Metabolites from Endophytic Fungi Isolated from Wheat (Triticum Durum)

Abstract: The emergence of antibiotic-resistant micro-organisms calls for inventive research and development strategies. Inhibition of these pathogenic micro-organisms may be a promising therapeutic approach. The screening of antimicrobial compounds from endophytes is a promising way to meet the increasing threat of drug-resistant strains of human and plant pathogens. In the present study, a total of 20 endophytic fungi and 23 endophytic actinomycetes have been isolated from wheat (Triticum durum). Mohamed Ben Bachir variety collected from Bordj Bou Arreridj region (Algeria) during winter 2010. The isolates were screened and evaluated for their antimicrobial and antioxidant activities. Antimicrobial activity was evaluated for crude ethyl acetate extracts using an agar dif-fusion assay against twelve pathogenic bacteria, yeast, and two phytopathogenic fungi. All extracts showed inhibitory activity on at least one or more pathogenic microorganisms, with an average zone of inhibition varied between 7 mm to 25 mm, and the largest zone was of 25 and 25.3 mm against candida albicans and Escherichia coli respectively. The antioxidant capacity of the extracts was evalu-ated by β-carotene/linoleic acid assay. Results showed that 60 % of these extracts have antioxidant activity, exhibiting 50, 57 % to 78, 96 % inhibitions. While the inhibitory activity for oxidation of linoleic acid of 40 % of them was less than 50%. From the present work it is possible to conclude that these microorganisms could be promising source of bioactive compounds, and warrant further study. Key words: endophytic microorganisms, antimicrobial activity, antioxidant activity, Triticum duru

Furanones and Anthranilic Acid Derivatives from the Endophytic Fungus Dendrothyrium variisporum.

Extracts from an endophytic fungus isolated from the roots of the Algerian plant Globularia alypum showed prominent antimicrobial activity in a screening for novel antibiotics. The producer organism was identified as Dendrothyrium variisporum by means of morphological studies and molecular phylogenetic methods. Studies on the secondary metabolite production of this strain in various culture media revealed that the major components from shake flasks were massarilactones D (1) and H (2) as well as two new furanone derivatives for which we propose the trivial names (5S)-cis-gregatin B (3) and graminin D (4). Scale-up of the fermentation in a 10 L bioreactor yielded massarilactone D and several further metabolites. Among those were three new anthranilic acid derivatives (5-7), two known anthranilic acid analogues (8 and 9) and three cyclopeptides (10-12). Their structures were elucidated on the basis of extensive spectroscopic analysis (1D- and 2D-NMR), high-resolution mass spectrometry (HRESIMS), and the application of the modified Mosher's method. The isolated metabolites were tested for antimicrobial and cytotoxic activities against various bacteria, fungi, and two mammalian cell lines. The new Metabolite 5 and Compound 9 exhibited antimicrobial activity while Compound 9 showed cytotoxicity activity against KB3.1 cells

Contribution to pharmacological valorisation of Algerian arctium minus (Hill) bernh. subsp. atlanticum (Pomel) maire; antioxidant and acetylcholinesterase inhibitory activities

The traditional pharmacopoeia is full of potential resources for molecules with therapeutic effects involving the inhibition of enzymes linked to some diseases. Objective: This work aimed to test in vitro neuroprotective activity against Alzheimer's disease (AD) combined with the antioxidant effect of root extracts obtained by water, water/methanol, and ethyl acetate of the endemic Arctium minus. subsp. Atlanticum, a native of Algeria. Methods: The different extracts of the root of the studied plant were obtained by decoction or maceration. The inhibitory effect of acetyl/butyrylcholinesterase (AChE/BChE) was achieved by a colorimetric method. Similarly, the antioxidant activity was measured based on several mechanisms: 1, 1diphenyl-2-picryl-hydrazyl (DPPH) and galvinoxyl (GOR) radicals free scavenging assays, β-carotene bleaching inhibition activity, and cupric ion reducing antioxidant capacity (CUPRAC). Results: In the various tests carried out, the ethyl acetate extract (EAE) possessed the most powerful antioxidant and anticholinesterase activities compared to the other samples. The IC50 and A0.5 values of DPPH, GOR, β-carotene, CUPRAC, anti-AChE, and anti-BChE assays were 69.45±5.49, 28.87±0.18, 121.58±16.76, 37.41±1.59, 265±21, and 240±6.3 µg / mL, respectively. Likewise, a correlation could be deduced between the type of extract and the potent antioxidant/anticholinesterase potential. Conclusion: This work examines for the first time the anticholinesterase potential combined with the antioxidant effect of Algerian Arctium minus. subsp. atlanticum. This association between the two effects could be effective in the fight against AD, and therefore, the use of this natural resource may be possible in combating this aspect of neurodegeneration

Antioxidant and radical scavenging properties of Carthamus caeruleus L extracts grow wild in Algeria flora

Four sub-fractions of Carthamus caeruleus L (whichbelongs to the family Asteraceae) root extracts, i.e., methanol (CE), chloroform (CHE), ethyl acetate (EAE) and aqueous (AE) extracts were screened for their total phenolics, flavonoids and possible antioxidant activities, using DPPH free radical-scavenging and β-carotene/linoleic acid assays. The results indicated that total polyphenols were highest in EAE followed by CHE. However, the free radical scavenging activity of CHE was higher than the other extracts with an IC50 value of 53.26 µg/mL. Determination of quercetin, gallic acid and rutin showed antioxidant activity as positive controls in parallel experiments. Moreover, oxidation of linoleic acid was effectively inhibited by AE, EAE and CE which were too close to each other. Also, the CHE was more effective compared to the synthetic antioxidant BHT. It could be concluded that Carthamus caeruleus L growing wild in the Mediterranean regions and especially in Algeria has a potent antioxidant activity and could be evaluated as a starting point for further investigations.Four sub-fractions of Carthamus caeruleus L (which belongs to the family Asteraceae) root extracts,i.e., methanol (CE), chloroform (CHE), ethyl acetate (EAE) and aqueous (AE) extracts were screenedfor their total phenolics, flavonoids and possible antioxidant activities, using DPPH free radicalscavengingand β-carotene/linoleic acid assays. The results indicated that total polyphenols werehighest in EAE followed by CHE. However, the free radical scavenging activity of CHE was higherthan the other extracts with an IC50 value of 53.26 μg/mL. Determination of quercetin, gallic acid andrutin showed antioxidant activity as positive controls in parallel experiments. Moreover, oxidation oflinoleic acid was effectively inhibited by AE, EAE and CE which were too close to each other. Also,the CHE was more effective compared to the synthetic antioxidant BHT. It could be concluded thatCarthamus caeruleus L growing wild in the Mediterranean regions and especially in Algeria has apotent antioxidant activity and could be evaluated as a starting point for further investigations. Propriedades dos radicais antioxidantes extraídos de Carthamus caeruleus L nativosda flora da ArgéliaQuarto sub-frações extraídas da raiz de Carthamus caeruleus L (que pertencem à famíliaAsteraceae), i.e., metanol (CE), clorofórmio (CHE), acetato de etil (EAE) e extratos aquosos foramexaminados minuciosamente quanto aos seus fenólicos, flanóides e suas atividades antioxidantespossíveis, usando DPPH extração de radicais livres e B-caroteno/ácido linoléico. Os resultadosindicaram que os polifenóis totais foram maiores em EAE seguido de CHE. Entretanto, a atividadede extração de radicais livres em CHE foi maior que de outros extratos com um valor de IC50 de of5326 μg/mL. A determinação de quercetina ácido gálico e rutina demonstrou que a atividade deantioxidante funciona como controle positive em experimentos paralelos. Além disso, a oxidaçãode ácido lenoico foi efetivamente inibida por AE, EAE e CE que estavam muito próximos uns aosoutros. Também, o CHE foi mais eficaz se comparado ao antioxidante sintético BHT. Foi possívelconcluir que Carthamus caeruleus L nativos das nas regiões do Mediterrâneo, e, especialmente naArgélia, tem uma potente atividade antioxidante e poderia ser avaliada como o ponto de partidapara investigações futuras