الفهرس 
Review of literatureOnly 14 pages are availabe for public view
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Abstract
Actinomycetes Are A Rich Source Of The Microbial Natural Products Whereas Streptomyces Resemble The Most Important Species Among This group Of Bacteria In Terms Of Production Of The Biologically Active Secondary Metabolites. Metabolomics-Guided Approach Was A Nascent Approach Used During The Last Few Decades As A Promising Tool For Both Targeting And Isolating New Microbial Secondary Metabolites With Various Biological Activities. The Main Aim Of The Present Study Was To Use Different Metabolomics Tools For Microbial Natural Products Discovery from Actinomycetes. In The Current Study, Different Metabolomics Tools Such Multivariate Analysis (MVA) And Dereplication As Well As The Antimicrobial Activity Results Were Used To Compare Both The Chemical Profiles And The Biological Activities Of The Crude Extracts/Fractions To Prioritise Either The Isolates Or The Fractions Prior To Further Isolation And/Or Elucidation Work. from A Total Of 58 Actinomycetes Isolates Recovered from Soil Samples from Egypt, 25 Isolates Showed Bioactivity Against At Least One Of The Tested Standard Strains. Using A Metabolomics- And Bioassay-Guided Approach, Two Anti-Methicillin Resistant Staphylococcus Aureus (MRSA) Isolates (Streptomyces Sp. MS.REE. 13 And Streptomyces Sp. MS.REE. 22) With Interesting Chemical Profiles And Broad Antibacterial Activity Against All Tested Bacterial Strains Were selected For Further Scaling-Up To Isolate Some New Bioactive Metabolites. After Scaling-Up Of Both selected Isolates, Both Metabolomics-Guided Tools And The Antimicrobial Activity Screening Were Used Successfully To Aid Isolation Of Nine Bioactive Metabolites from selected Isolates Using Different Flash chromatographic Techniques. Interestingly, Two Compounds; (4E)-6-Oxooctadec-4-Enoic Acid And (4-Propylphenyl) Methanediazonium Were Isolated For The First Time As Natural Products from Streptomyces Sp. MS.REE. 22 And Streptomyces Sp. MS.REE. 13, Respectively. Moreover, Another Compound; (9E)-11-Hydroxyoctadec-9-Enoic Acid Was Isolated from Streptomyces Sp. MS.REE. 22 For The First Time As Streptomyces’ Metabolite While 8-Methyl-5-Oxononanoic Acid Was Isolated from Streptomyces Sp. MS.REE. 13 For The Second Time As A Natural Product. Interestingly, All Isolated Compounds Showed Antimicrobial Activity Against MRSA. Finally, Metabolomics-Guided Approach Was Used For Optimization Of The Culture Conditions Of The selected Isolates To Best Produce Their Isolated Bioactive Compounds. It Was Concluded from The Current Study That Combining Both Metabolomics And Bioassay Results In Programs Of The Natural Products Discovery Was A Valuable Approach Aiding Isolation Of Some New Bioactive Compounds Which Was The Main Aim Of The Present Study.