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The new cytotoxic agents rakicidins A and B were isolated from cultured broth of a Micromonospora sp. Spectroscopic and amino acid analysis has shown that rakicidin A is a new cyclic lipopeptide, consisting of 4-amino-penta-2,4-dienoic acid, 3-hydroxy-2,4,16-trimethylheptadecanoic acid, sarcosine, and 3-hydroxyasparagine. Rakicidin B differs by one methylene group in the lipid side chain. These compounds exhibited cytotoxicity against the Ml09 cell line. In our continuing search for newantitumor agents from microorganisms, an isolate of Micromonospora was selected for further evaluation. This research led to the discovery of two newcytotoxic lipopeptides, rakicidins A and B (Fig. 1). This paper describes the fermentation, biological evaluation, purification, physico-chemical characterization, and structure elucidation of these compounds. Fermentation Microorganism The producing organism was isolated from a soil sample collected at Andhra Pradesh, India and was identified as a Micromonospora sp., strain No. R385-2. Media and Culture Conditions Micromonospora strain No. R385-2 was grown on slants of modified Bennett's mediumwhich contained the following: 0.5% Japanese potato starch (Generichem DEC. 1995 Corp. Acadama Dextrin No. 3), 0.5% glucose, 0.1% fish meat extract (Mikuni Chem. Industry), 0.1% yeast extract (Difco), 0.2% N-Z Case (Sheffield Products), 0.2% NaCl, 0.1% CaCO3, 1.5% agar. The medium was sterilized at 121°C for 20 minutes. The culture was transferred from the slant into 100ml of GERmedium in a 500ml flask. The medium contained the following: 2.4% Japanese potato starch, 0.1% dextrose, 0.3% beef extract (BBL), 0.5% tryptone (Difco), 0.5% yeast extract (BBL), 0.2% CaCO3 and was adjusted to pH 7.6 before autoclaving. The mediumwas sterilized at 121°C for 20

Eupenifeldin was isolated from cultures of Eupenicillium brefeldianum ATCC741 84 by extraction and crystallization.The compoundwas identified as a pentacyclic bistropolone on the basis of spectral data and its complete structure was established by single-crystal X-ray analysis. The compound is cytotoxic against the HCT-1 16 cell line and has in vivo antitumor activity in the P388 leukemia model.Ongoing efforts to find new natural products with antitumor activity led to isolation of a novel cytotoxic bistropolone from a culture broth produced by Eupenicillium brefeldianum ATCC74184. The active principle of this culture was purified to homogeneity and namedeupenifeldin. Its spectral data showed that the molecule had partial symmetry due to the presence of two identically substituted tropolone units each fused in the same mannerto dihydropyran rings. The complete structure and relative stereochemical relationships were determined by single crystal X-ray analysis. Only one naturally occuring bistropolone with cytotoxic activity, fusariocin C, has been described previously in the literature.1>2) It was isolated from the culture filtrate of Fusarium moniliforme and had cytotoxic and antitumor activities. Bistropolones madeby chemical synthesis have also been reported to possess antitumor activity.3) This report describes isolation, physico-chemical characterization, biological properties and the structure of eupenifeldin. Materials and Methods Spectral DataMass spectra in the FABmodewere obtained on a Kratos MS25using m-nitrobenzylalcohol as matrix. El spectra were recorded on a Finnigan TSQ70. A Shimadzu UV2100Uspectrophotometer was used for UVspectra and a Perkin-Elmer FTIR Model 1800 spectrometer for IR spectra. All NMRspectra were recorded in CDC13with a drop ofDMSO-d6on a Bruker Model AM-500spectrometer. Proton-proton coupling constants were obtained by selective irradiations, and carbon-proton one-bond coupling constants were measured in the proton coupled carbon spectrum.El mass spectrum: major peaks at m/z 548, 384, 366, 175, 137. IR-spectrum (KBr): 3440, 3260, 2950, 2870, 1630, 1595, 1530, 1445, 1425, 1395, 1280, 1178, 1150, 1082 cm"1. Fermentation ConditionsTo prepare an inoculum for the production phase, 4 rnl of the frozen vegetative stock were transferred to a 500-ml Erlenmeyer flask containing 100ml of vegetative mediumconsisting of soluble starch 0.5%, glucose 0.5%, fishmeat extract 0. 1 %, yeast extract 0.1 %, NZ-case 0.2%, sodium chloride 0.2% and calcium

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