Studies On The Secondary Metabolites From Two Streptomyces Strains

The mutants of Streptomyces sp. LZ35and QH13were chemically investigated. A total of29compounds including25new ones were obatained by column chromatography on silica gel, RP-18, Sephadex LH-20and HPLC. The structures were determined on the basis of UV, IR, MS and NMR. Some of the isolated compounds were tested for their antimicrobial and antitumor activities. Additionally, We also investigated the biosynthesis of hygrocins.Five new p-terphenyl O-β-glucuronosides, ecosides A-E (1-5); three new triene carboxylic derivatives, cuevaenes C-E (8-10); two new isoflavone4"-dehydrate-O-β-glucuronosides (11-12) were obtained from the cultivation of mutant LZ35ΔGdmAI. Three new hygrocins, DHA3(13), DHA4(14) and DHA5(15) were obtained from the cultivation of mutant LZ35ΔGdmAI+HYG-LuxR. Four new hygrocins, DJ-1-4(16-19) were obtained from the cultivation of mutant SR307ALT. Additionally, to investigate the roles of oxidase genes played in the hygrocin gene cluster, eight OX genes were inactivated, the MO2, MO3, P450disruption mutants abolished the production of hygrocin, confirming their involvement in the hygrocin biosynthesis. The prohygrocins (22-27) were isolated from the metabolites of ΔMO3mutant, which indicated that MO3gene is probably involved in a Baeyer-Villiger oxidation, which is typically catalyzes the insertion of an oxygen atom into carbon skeletons adjacent to carbonyl groups. Finally, we proposed the biosynthetic pathway of hygrocins in_Streptomyces sp. LZ35.Two new compounds DA-2(20) and DA-3(21) were obtained from the cultivation of mutant LZ35ΔGdmAI+NAS-ASc. Two ansatrienin analogues (28-29) were isolated from the cultivation of mutant QH13Asr-LuxR.