Preliminary Study On Secondary Metabolites Of Three Actinomyces From Cold And Drought Soils And Their Biological Activities

Actinomycetes are recognized as biosynthetic factories,which produce a wide range of secondary metabolites and are the source of new drug discovery.At present,most of the research focuses on soil actinomycetes,but with the deepening of the research,the frequency of finding new candidate drugs began to decline.In order to solve this problem,more and more researchers have turned their attention to actinomycetes in special habitats.These strains have special metabolic and physiological functions due to the influence of the environment,and may produce metabolites with novel structures and diverse activities.In this paper,the secondary metabolites of three strains of actinomyces from cold and arid soils in Tibet were isolated,purified,identified and their anti-inflammatory or anti-tumor activities were studied.The strain TB060207 was fermented on GAU medium,and the crude extract was obtained by extraction.The compounds were separated by silica gel column chromatera-phy,octadecyl silane,thin layer chromatography,gel chromatography and RP-HPLC.Four known anthraquinone compounds were obtained,1-hydroxy-6-methoxy-8-methy-lanthraquinone(TB01),9’-hydroxyaloesaponarin Ⅱ(TB02),3,8-dihydroxy-1-methyla-nth-raquinone-2-carboxylic acid(TB04)and aloesaponarin Ⅱ(TB12).The anti-inflam-matory activity of these compounds was studied,and it was found that TB12 had weak anti-inflammatory activity.At the concentration of 40 μM,the inhibition rate was 70.89%.The strain TB060214 was fermented on GAU medium,and nine polyene carboxylic acids were isolated from the fermentation broth of strain TB060214,include-ing six novel compounds,serpentemycin E-J and three known analogues:serpentmyc-in C(TB13),serpentemycin B(TB14)and(2Z,4E,6Z)-7-(2-((1E,3E)-4-carboxybuta1,3-dien-1-yl)phenyl)hepta-2,4,6-trienoic acid(TB15).These compou-nds are open-ch-ain polyenes with more than two conjugated double bonds centered on ortho-substitut-ed benzene rings.The anti-inflammatory activity of these compounds was studied,and it was found that TB12 had weak anti-inflammatory activity.At the concentration of 40μM,the inhibition rate was 60.53%.The whole gene sequence of Streptomyces sp.TB 160215 was analyzed by antiSM-ASH 5.0 soft were indicated the presence of 34 biosynthetic gene clusters and the predicted secondary metabolites,macrolides(filipin),Aureolic acids(mithramycin).The strain TB060214 was fermented on GAU medium,and ten auric acid compounds were isolated from TB160215,including two new compounds,mithramycin B and premithramycin C,and eight known compounds:8-mycarosyl-12a-olivosylchromocyclin(TB17),deoliosyl-3C-β-D-mycarosyl-mithramycin(TB18),demycarosyl-mithram-ycin(TB21),8-mycarosyl-12a-oliosylolivosylchromocyclin(TB23),premithramycin A3(TB24),4E-acetyl-mithramycin(TB25),premetathramycin(TB26)and mithramy-cin(TB27).4E-acetyl-mithramycin(TB25)and mithramycin(TB27)can effectively inhibit the cell activity of breast cells MCF-7,MDA-MB-231,MDA-MB-453,and MCF-10A.Scratch healing and Transwell experiments showed that mithramycin(TB 27)showed dose-dependent anti-migration and anti-invasion effects on invasive triple negative breast cancer cell line MDA-MB-231.The results show that actinomycetes from special environment are rich in second-dary metabolites,which can produce compounds with unique structure and good biol-ogical activity,and can be used as an important source of new natural products,thus providing important strain resources for new drug development in the future.