Study On Secondary Metabolites Of Three Special Streptomyces Sp.

Since the discovery of penicillin,a number of natural products and its derivative related with microorganisms have been applied to clinical treatments.However,many microbial secondary metabolites were repeatedly isolated under the experimental conditions,making it difficult to explore new drug molecules.Microorganisms could produce special metabolites under the harsh survival environment.Thus,Streptomyces sp.in samples collected from specific environment might produce secondary metabolites with excellent activities and novel skeletons,which would inspire new ideas for drug developments.We select three streptomyces sp.from special habitats for secondary metabolite research,including a cold-tolerant plant endophytic and two marine-derived actinomycetes.Through isolation,fermentation and structure identification,we isolated 15 compounds,including 6 new compounds.We tested the activity of the new compounds.Related results are as follows:A strain of Streptomyces sp.,named NA06554,was isolated from a cold-tolerant plant Aster tataricus L.f.in Aba County,Sichuan Province.By large scale fermentation,six compounds(including three new compounds)have been isolated.By activity test,it was found that compound 1 and 6 have inhibitory activity against Micrococcus luteus and MIC values are 1μM and 40μM respectively.Another Streptomyces sp.was isolated from sea sand sample in Halong Bay,Vietnam,named NA02482.The strain was fermented on a large scale and the secondary metabolite was obtained by resin adsorption.Five compounds were finally isolated,including three new compounds.Similarly,we screened the activity of new compounds,but these compounds did not show significant biological activity.The other type isolated was a marine Streptomyces sp.from a marine sludge sample which collected from Halong Bay,Vietnam.Then it was subjected to fermentation and as a result four known compounds were isolated,compounds 14 and 15 showed activity against Cryptosporidium.In addition,we reviewed the research progress of type I polyketones natural products.