P-39 New Cyclic Peptides from the Cordyceps, Ophiocordyceps heteropoda and the Marine Bacterium Photobacterium sp.(Poster Presentation)

Abstract

As a part of our research program on bioactive metabolites of the Cordyceps and marine microorganisms, several cyclic peptides were isolated. We would now like to report the isolation and structure determination of these new compounds. Chemical studies of Ophiocordyceps heteropoda led to the isolation of two new cyclic peptides, 1 and 2. Furthermore nine new depsipeptides (3-11) with known compounds were isolated from the fermentation broth of a marine bacterium, Photobacterium sp. These compounds exhibited weak antimalarial activity against drug-resistant (K1) and drug-susceptible (FCR3) strains with IC_<50> values of 6-10 μg/ml. 1,2 and 5 showed selective activity for malaria parasite. (Fig 2) The antiproliferative activity for these compounds was evaluated with MTT method in four cell lines (HL-60, HeLa, HCS-2 and HSC-2). Analogous compounds of kailuin showed modest activity in all cell lines, especially kailuin E inhibited the growth of HeLa cells with IC_<50> < 1 μM.