Isolation and structural determination of the antifouling diketopiperazines from marine-derived Streptomyces praecox 291-11.
Marine derived actinomycetes constituting 185 strains were screened for their antifouling activity against the marine seaweed, Ulva pertusa, and fouling diatom, Navicula annexa. Strain 291-11 isolated from the seaweed, Undaria pinnatifida, rhizosphere showed the highest antifouling activity and was identified as Streptomyces praecox based on a 16S rDNA sequence analysis. Strain 291-11 was therefore named S. praecox 291-11. The antifouling compounds from S. praecox 291-11 were isolated, and their structures were analyzed. The chemical constituents representing the antifouling activity were identified as (6S,3S)-6-benzyl-3-methyl-2,5-diketopiperazine (bmDKP) and (6S,3S)-6-isobutyl-3-methyl-2,5-diketopiperazine (imDKP) by interpreting the nuclear magnetic resonance and high-resolution mass spectroscopy data. Approximately 4.8 mg of bmDKP and 3.1 mg of imDKP were isolated from 1.2 g of the S. praecox 291-11 crude extract. Eight different compositions of culture media were investigated for culture, the TBFeC medium being best for bmDKP and TCGC being the optimum for imDKP production. Two compounds respectively showed a 17.7 and 21 therapeutic ratio (LC50/EC50) to inhibit zoospores, and two compounds respectively showed a 263 and 120.2 therapeutic ratio to inhibit diatoms.
Department of Marine Biotechnology, Soon Chun Hyang University, Asan, Korea. jycho@sch.ac.kr
Ji Young
JY
Cho
Ji Young
JY
Kang
Yong Ki
YK
Hong
Hyo Hyun
HH
Baek
Hyoun Woong
HW
Shin
Myoung Sug
MS
Kim
D000890:Anti-Infective Agents / Q000302:isolation & purification* / Q000494:pharmacology; D059001:Aquatic Organisms; D045424:Complex Mixtures / Q000737:chemistry; D003470:Culture Media; D017377:Diatoms / Q000187:drug effects / Q000254:growth & development; D054659:Diketopiperazines / Q000302:isolation & purification* / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D007928:Lethal Dose 50; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D012336:RNA, Ribosomal, 16S / Q000032:analysis* / Q000235:genetics; D058441:Rhizosphere; D012623:Seawater; D013170:Spores / Q000187:drug effects / Q000254:growth & development; D013302:Streptomyces / Q000737:chemistry*; D044445:Ulva / Q000187:drug effects / Q000254:growth & development; D044648:Undaria / Q000737:chemistry*
D000890:Anti-Infective Agents; D045424:Complex Mixtures; D003470:Culture Media; D054659:Diketopiperazines; D012336:RNA, Ribosomal, 16S