Studies On The Kaloids From Two Strains Of Marine-derived Actinomycetes

The oceans are highly complex environments, which contain a diverseassemblage of microbes that occur in environments with extreme variations inpressure, salinity, and temperature. Marine actinomycetes as an important source oflead compounds have attracted tremendous attention since they posses uniquephysiological and metabolic functions that not simply ensure survival in extremesurroundings, but also are further endowed with the potential to produce compoundswith antitumor and other interesting biological activities that would not be observed intheir terrestrial counterparts. such as aclarubicin, daunomycin and doxorubicin, whichare antitumor compounds from marine actinomycetes.The secondary metabolites of two active strains were setted aside based onintegrated screening that combines the cytotoxic effect against MCF-7cells andHPLC. Among them, Streptomyces parvulus OUCMDZ-2554was picked out forfurther study of its secondary metabolites, which mainly produces one compound. Toenhance the productivity of actinomycin D from S. parvulus OUCMDZ-2554byoptimization of the fermentation conditions.The optimal composion of the medium,the inoculum age and size, temperature, liquid volume, pH, salinity and cultivationtime were investigated by single-factor experiment and the orthogonal matrix methods.And the structure of actinomycin D was identified by means of spectroscopic analysisand physical properties. The optimum culturing medium was as following: K2HPO41.5g, MgSO40.5g, yeast extract5g, soluble starch22.5g, sea water1000mL. Andthe best fermentation conditions are150mL of culture medium in500mL conicalflask,4d old of inoculum age and3%of salinity, pH=7.5, and shaking in an orbitalshaker (180rpm) for12d. The best yield (364mg/L) of actinomycin D is obtainedunder the optimal fermentation conditions, which is3.6-fold high as the originalcondition.To study secondary metabolites produced by Streptomyces sanyensis FMA froma soil sample collected in Sanya, Hainan Province of China,5-OH-L-tryptophan wasadded to the medium. Metabolites were extracted with EtOAc. Twelve compounds(Table1) were isolated by silica gel, Sephadex LH-20and semi-preparative HPLC.Their structures were established by spectroscopic analysis and physical properties,three of which are new indolocarbazole compounds (1-3). The structure types compose of indolocarbazole alkaloids (1-9), simple indole derivatives (10-12).Indolocarbazole alkaloids remain a major structural type of metabolites of this strain.By means of gas chromatography-mass spectrometry, the structure of one compoundwas determined.In summary, thirteen compounds have been isolated from the two marineactinomycetes, in which only one compound is produced by S. parvulus OUCMDZ-2554. The best yield of actinomycin D has been obtained under the optimalfermentation conditions, which is3.6-fold high as the original condition. The studyprovides a new strain for production of actinomycin D with potential industrial use.Thirteen alkaloids compounds were obtained from Streptomyces sanyensis FMA,including three new indolocarbazole alkaloids. The new indolocar bazoles wereachieved by cultivation of S. sanyensis OUCMDZ-4224in the medium containing5-OH-L-tryptophan. Ocean is a potent source of antitumor compounds. The studyprovides new compounds and candidates, which also provides important marinemicrobial resources.