Abstract:

This study aims to investigate the antibacterial components of marine-derived actinomycete Streptomyces sp.11695 guided by antibacterial activity,and identify their structures on the basis of their physicochemical properties.Six compounds were isolated from the extracts of marine-derived Streptomyces sp.11695 by bioactivity guided isolation method,which is fermented in AM3 medium.These compounds are identified as mucidone (1),dixiamycin B (2),xiamycin A (3),xiamycin B (4),nocapyrone A (5),and lobophorin CR1 (6),respectively,on the basis of their MS and NMR spectroscopic data.Compounds 1-6 was isolated from the strain of Streptomyces sp.11695 for the first time.Antibacterial activity results showed that compounds 2,3,4,6 showed good antimicrobial bioactivity,among them compound 2 showed the minimum inhibitory concentration (MIC) value of 1.1-4.5 μg/mL.Compounds of three types were simultaneously isolated and identified from Streptomyces sp.11695 by changing fermentation medium,which further confirmed that this strain has the ability to synthesize multiple secondary metabolites.

Key words:

xiamycin, nocapyrone, lobophorin, marine actinomycetes, secondary metabolisms