Study On Secondary Metabolites And Bioacttivities Of Four Streptomyces

Streptomyces are crucial source for searching novel antibiotics as they can produce innu-merable fantastic active secondary metabolites.Fermentation of Streptomyces,purification and structural elucidation of bioactive secondary metabolites can provide novel biactive compounds for drug discovery.Herein,we report the fermentation,structural elucidation and their bioactivities assay of four Streptomyces.Their crude extracts were separated by silica gel column chromatography and the final purification was performed by semi-preparative reversed-phase HPLC and Sephadex LH-20.Besides one new natural product,25 compounds were identified from the fermentation cultures of the microbial materials.Their structures were determined by 1D and 2D NMR,and?HR-ESI?MS spectroscopic analysis.The results are concluded as follows:1.Six known metabolites,namely,3-methyl-N-?2'-phenylethyl?-butyramide?2-1?,Talosins A?2-2?,5,7-[?6-deoxy-L-mannopyranosyl?oxy]-3-?4-hydroxy phenyl?-4H-1-Ben-zopyran-4-one?2-3?,Tyrosol?2-4?,Seco-??S?-Pro-?R?-Val??2-5?and Indole-3-carbox-aldehyde?2-6?,were isolated from the culture broth of S.xanthophaeus D61.Activity tests showed compounds 2-1 and 2-3 inhibited against F.oxysporum?K15-1?,yeast and Verticillium dahliae.2.A new compound?3-9?,together with seven known metabolites,BE-14106?3-1?,GT32-B?3-2?,heronamide H?3-3?,heronamide I?3-4?,novobiocin?3-5?,2''-?O-carbanyl?-novobiocin?3-6?,4-hydroxy-3-?3-methyl-2-butenyl?benzamide?3-7?,4-hydroxy-3-?3-methyl-2-butenyl?benzoic acid?3-8?,3-isopropyl-6,7-dihydropyrrolopyrimidin-1?5H?-one?3-9?,were isolated from the extracts of the terrestrial-derived Streptomyces sp.DJ21.Most of the metabolites were evaluated in vitro for antibacterical activities against phytopathogenic fungi and bacteria.Novobiocin?3-5?displayed potent antimicrobial activities against Bacillus subtilis,Staphylococcus aureus ATCC 6538,and Escherichai coli ATCC 8099.At concentration value of 2 mg/mL,it showed strong inhabited the growth of Escherichai coli ATCC 8099in the antimicrobial diameter of 12.3 mm surpass kanamycin?in 10.4 mm?.While antibaterical activities against Bacillus subtilis and Staphylococcus aureus ATCC 6538 are prior to positive control.3.Six known metabolites,Chartreusin?4-1?,ObscurolideA2?4-2?,ObscurolideA4?4-3?,Obscurolide B2?4-4?,Ochromycinone?4-5?,resomycinA?4-6?,were isolated from the extracts of the endophytic Streptomyces sp.f224,which was isolated from Mayterus Hookeri Loes.All isolates were evaluated in vitro for antibacterical activities against phytopathogenic fungi and bacteria.Compound 4-1 showed potent antimicrobial activities against Bacillus subtilis,at concentration value of 2 mg/mL,approximate to positive control kanamycin.4.Five known metabolites,ChromomycinA₃?5-1?,ChromomycinA₂?5-2?,Dihydroch-romomycinA₂?5-3?,D-chromose A-D-chromomycinone-D-chromose C?5-4?,5-hydroxy-7-?2'-hydroxypropyl?-2-methyl-chromone?5-5?,were isolated from the extracts of the Streptomyces sp.2057,an endophyte isolated from Cajanus scarabaeoides?Linn.?Thouars.All of the isolates were evaluated in vitro for antibacterical activities against phytopathogenic fungi and bacteria.Compounds 5-1³ can significantly inhibit the growth of three bacterias?Bacillus subtilis,Staphylococcus aureus ATCC 6538,and Escherichai coli ATCC 8099?at the concen-tration of 2 mg/mLwhich are superior to the positive control kanamycin.