Isolation and characterization of two novel antibacterial cyclic hexapeptides from Streptomyces alboflavus 313.
Two novel cyclic hexapeptides, designated NW-G08 (1) and NW-G09 (2), were isolated from the fermentation broth of Streptomyces alboflavus 313. Their structures were elucidated on the basis of extensive spectroscopic analysis, MS experiments, and chemical analysis. Their antibacterial activities against several strains of bacteria were evaluated by micro-broth dilution method. NW-G08 (1) and NW-G09 (2) were highly antibacterial against Gram-positive but not active against Gram-negative bactaria. The minimum inhibitory concentrations (MICs) of 1 against Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus were 6.25, 6.25, and 1.56 μg/ml, respectively. It is worth noting that 1 and 2 exhibited much higher activities against methicillin-resistant Staphylococcus aureus (MRSA) than ampicillin, which implies that they might be potential candidates for the development of novel drugs against resistant pathogenic bacteria.
State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, PR China. jizhiqin@nwsuaf.edu.cn
Zhiqin
Z
Ji
Gang
G
Qiao
Shaopeng
S
Wei
Lixia
L
Fan
Wenjun
W
Wu
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001424:Bacterial Infections / Q000188:drug therapy; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D009842:Oligopeptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000188:drug therapy; D013302:Streptomyces / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D009842:Oligopeptides; D010456:Peptides, Cyclic