Streptomyces is the most frequently described genus of Actinomycetes, a producer of biologically active secondary metabolites. Indeed, the Streptomyces species produces about 70% of antibiotics and 60% of antifungal molecules used in agriculture. Our study was carried out with the goal of isolating and identifying antimicrobial secondary metabolites from Streptomyces misionensisV16R3Y1 isolated from the date palm rhizosphere (southern Tunisia). This strain presented a broad range of antifungal activity against Fusarium oxysporum, Aspergillus flavus, Penicillium expansum, Aspergillus niger, Candida albicans, Candida metapsilosis, and Candida parapsilosis and antibacterial activity against human pathogenic bacteria, including Escherichia fergusonii, Staphylococcus aureus, Salmonella enterica, Enterococcus faecalis, Bacillus cereus and Pseudomonas aeruginosa. The purification procedure entailed ethyl acetate extract, silica gel column, and thin layer chromatography. Based on 1H NMR metabolomic procedure application, also supported by the GC-MS analysis, cyclic dipeptide (l-Leucyl-l-Proline) was identified as the major compound in the bioactive fraction. In order to confirm the identity of the active compound and to have a large quantity thereof, a chemical synthesis of the cyclic dipeptide was performed. The synthetic compound was obtained with a very good yield (50%) and presented almost the same effect compared to the extracted fraction. This study indicates for the first time that Streptomyces misionensis V16R3Y1 exhibits a broad spectrum of antimicrobial activities, produced cyclic dipeptide (l-Leucyl-l-Proline) and might have potential use as a natural agent for pharmaceutical and agri-food applications.

中文翻译：

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从misionensis misionensisV16R3Y1细菌提取物中提取的广谱抗菌环二肽（1-leu-1-pro）的分离，表征和化学合成。一种新颖的1H NMR代谢组学方法。

链霉菌是放线菌属中最常描述的属，其是具有生物活性的次生代谢产物的产生者。的确，链霉菌产生了约70％的抗生素和60％的农业用抗真菌分子。我们的研究旨在从分离自枣棕根际（突尼斯南部）的米链链霉菌V16R3Y1中分离和鉴定抗菌次级代谢产物。该菌株呈现宽范围的抗真菌活性的尖镰孢，曲霉FL AVUS，青霉-扩展，黑曲霉，白色念珠菌，念珠菌metapsilosis，和念珠菌近平滑念珠菌和针对人病原性细菌，包括抗菌活性大肠杆菌fergusonii，金黄色葡萄球菌，肠道沙门氏菌，粪肠球菌，蜡状芽孢杆菌和铜绿假单胞菌。纯化步骤需要乙酸乙酯萃取液，硅胶柱和薄层色谱。基于1H NMR代谢组学方法的应用，也得到了GC-MS分析的支持，环二肽（1-亮氨酰-1-脯氨酸）被确定为生物活性部分中的主要化合物。为了确认活性化合物的身份并使其具有大量，进行了环状二肽的化学合成。以非常好的收率（50％）获得了合成化合物，并且与提取的级分相比呈现几乎相同的效果。这项研究首次表明米链霉菌 V16R3Y1具有广泛的抗菌活性，可产生环状二肽（1-亮氨酰-1-脯氨酸），可能具有潜在的天然用途，可用于制药和农业食品应用。