Secondary Metabolites Of Marine-derived Actinomycete Kocuria Sp.

Due to the environments of the ocean as high pressure,high salt,low temperature,low-oxygen and low-nutrient,marine-derived actinomycetes possess unique physiological characteristics which may be contribute to the production of diverse and bioactive metabolic compounds differed from these produced by terrestrial microorganisms.Recently,marine-derived actinomycetes attracted more attention for the capability of the re-production of target compounds.Main types of secondary metabolites are macrolide,cyclic peptides.These compounds possess potential bioactivities including acti-bacterial,acti-tumor,acti-inflammatory and acti-viral activities.The novel structures and activities stimulate the enthusiasm of many marine natural products workers.43 actinomycetes were isolated from 7 marine-derived coral samples.The actinomycetes were screened by using the chemical screening phases.In this process,TLC,HPLC and ~1H-NMR were used,and one target strain was selected for further study.According to the morphology and 16 S rDNA gene sequence analysis,this target strain then was identified as Kocuria sp.According to the strains source,the fermentation conditions were optimized including medium,pH,temperature.The whole broths were extracted with ethylacetate to give ferment extracts after the fermentation of the target strain under the optimal conditions.Then the extracts were subjected to extensive columnchromatography and HPLC to give pure compounds.And 20 compounds were obtained.By means of modern spectral analysis,the structures of twenty compounds were identified as: cyclo(L-Trp-L-Pro)(1),cyclo(L-Trp-D-Pro)(2),cyclo(L-Phe-D-Pro)(3),cyclo(L-4-hydroxyl-Pro-L-Phe)(4),cyclo(D-4-hydroxyl-Pro-L-Phe)(5),cyclo(L-4-hydroxyl-Pro-L-Tyr)(6),cyclo(L-Leu-D-Pro)(7),cyclo(L-Leu-L-Pro)(8),cyclo(L-Ile-D-Pro)(9),cyclo(L-Phe-L-Pro)2(10),cyclo(L-Phe-L-Tyr)(11),cyclo(L-Leu-D-Tyr)(12),cyclo(L-Leu-L-Tyr)(13),cyclo(L-Leu-L-Phe)(14),cyclo(D-Val-L-Phe)(15),cyclo(D-Val-D-Phe)(16),cyclo(D-Leu-Gly)(17),cyclo(D-Ile-Gly)(18),cyclo(L-Leu-L-Val)(19),N-acetyltryptamine(20).This presentstudy enriched the chemical diversities of secondary metabolites produced by marine-derived actinomycete Kocuria sp.Meanwhile all the compounds were isolated from the genus Kocuria for the first time,which would provide reference basis for the further development and utilization of Kocuria sp.