Studies On The Bioactive Constituents Of An Marine Actinomycete NO.9002

Marine microbe shows to be a potential reservoir for screening anticancer leading compounds, providing a wide variety of structurally unique, biologically significant products. Searching for anticancer product, we screened for novel cell cycle inhibitors and apoptosis inducers from the marine actinomycetes by use of a mouse cdcl mutant cell line, tsFT210.We have undertaken the screening for novel cell cycle inhibitors and apoptosis inducers from these marine actinomycetes by use of a mouse cdcl mutant cell line, tsFT210. Marine actinomycetes were isolated from seamud samples 20 meter below the sea level collected from Jiao Zhou Bay, China. 20 strain actinomycetes showed bioactivity of inhibiting the cell cycle progression and cytoclsis of tsFT210 cells. After preliminary experiments No. 9002 strain showed good bioactivity and was selected for further investigation. In anticipation of achieving the above objectives, the fermentation of 9002 was screened by using bioactivity model and their chloroform extract showed bioactivity of inhibiting the cell cycle progression and cytoclasis of tsF210 cells.The precipitate and supernantant of 9002 fermentation was extracted with CHCl3. The crude extraction was isolated by column chromatography on Sephadex LH-20, silica gel and RP18, followed by reverse-phase high performance liquid chromatography and recrystalization. The structures-of six compounds 1-6 and a pair of epimeric forms were elucidated mainly by use of spectroscopic method (UV, IR, MS, 1D-NMR, 2D-NMR) and according to their physicochemical properties: cyclo-(L-Pro-L-Leu) (1), cyclo- (Pro-Ala) (2), (S , Z) 3-Ethylidene-6- (1H- indol-3 - ylmethy ) - 4 - methyl - 2 , 5 - piperazinedione ( 3 ) , cyclo-( L-Pro-L-Tyr ) (4), cyclo- ( L-Pro-L-Val ) (5), 3, 4-Dihydroxy-2 -methylpyridine (6), cyclo- (Ala-He) (7-A, 7-B) . The structure of compound 8 are still in deducing.Bioassay results indicated that compound 1, 2, 3, 4, 6 showed bioactivity in inhibiting tsFT210 cell proliferation; compound 3 showed bioactivity in inhibiting the cell progression at the G0/G1 phase of tsFT210 cells and cytoclasis; compound 6 possessed cytoclasis.In summary, six compounds and a pair of epimeric forms were isolated from 9002 fermentation, including seven diketopiperazine and one pyridine compounds. The inhibitory activity on cell cycle and cytoclasis activity of compounds 3 and the cytoclasis activity of compound 6 were discovered for the first time.