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Start date: 2024End date: 2024

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    Activités biologiques et caractérisations biochimiques des extraits de la plante Peganum harmala: effet sur la cinétique de croissance et production des métabolites des actinomycètes (Streptomyces ayarius sp. S115)
    (2024) Nait Marzoug Amel
    This work contributes to the study of the biological activities of different extracts obtained from the plant Peganum harmala L. and their effect on the growth and production of secondary metabolites of Streptomyces ayarius strainsp. S115. A phytochemical screening was performed to identify the main chemical groups present. Quantitative analysis was done by measuringthe totalpolyphenol and flavonoid content.The antioxidant power of extracts was evaluated in vitro by eight different methods.Enzymatic activity wasestimated by Ellman's method.The morphological characteristics and antibacterial activity of S. ayarius strain sp. S115 seeded in ISP2and the modified ISP2 media was evaluated by well diffusion method.Thebiomass of S. ayarius strain sp. S115 in both media was determined. Growthkinetics and productionof secondary metabolites were studied for 7 days in different carbon and nitrogen sources. The phytochemical screening revealed the presence of numerous classes of secondary metabolites.The ethyl acetate fraction contained the highest content of polyphenols and flavonoids(237.23 ± 1.06 μg GAE/mg of extract and 82.58 ± 0.03 μg QE/mgof extract, respectively).The ethyl acetate fraction with high phenolic content also exhibited the strongest antioxidant activity.In addition, the chloroform fraction showed the most potent inhibitory effect against acetylcholinesterase and butyrylcholinesterase(IC50: 14.69 ± 0.10 and 7.36 ± 0.77 µg/ml, respectively).Culture on the modified ISP2 showed an effective growth of S. ayarius strain sp. S115 with changedcolor of the aerial mycelium from gray to white.The antibacterial activity revealed large inhibition zonesagainst the tested pathogenic bacteria compared to those of ISP2with inhibition zones ranging from 13.5 mm to 60.5 mm. Thus, the amount of S. ayarius strain sp. S115biomass was twice as high in the modified ISP2.The effect of different carbon and nitrogen sources on the growth andproduction of secondary metabolites of S. ayarius strain sp. S115 revealed the highest biomass and antibacterialactivities were obtained through using glucose and tryptone in the modified ISP2, whereas glycerol and yeast extract were found as the optimal carbon and nitrogen sources in ISP2.The present study confirmed the effectiveness of the plant as an important ingredient in the ISP2 medium required for the culture of antibiotic-producing Streptomyces andprovided measurable biological proof of its antioxidantand anti-cholinesterase power.