During our search for new antiprotozoal (antimalarial and antitrypanosomal) agents, we have tested culture extracts of soil microorganisms from a variety of sources, including those isolated by the Kitasato Institute for Life Sciences and the Bioresource Laboratories, MicroBiopharm Japan Corporation. We have previously discovered a variety of microbial metabolites exhibiting antiprotozoal, 1,2 antimalarial 3,4 and antitrypanosomal properties. 5,6 Recently, we have isolated a new derivative of pactamycin, designated as jogyamycin (Figure 1), from a culture broth of Streptomyces sp. a-WM-JG-16.2. This compound has proved to have potent antiprotozoal activity (Table 2). Here, we report the fermentation, isolation, structure elucidation and biological activity of this novel aminocyclopentitol antibiotic.The producing organism, strain a-WM-JG-16.2 was isolated from a soil sample collected in Jogjakarta, Indonesia, using the sucrose density gradient centrifugation method. 7 Using the basic local alignment search tool (BLAST), we compared the 16S rRNA gene sequences available in the EzTaxon server to identify the species of strain a-WM-JG-16.2. Streptomyces sp. a-WM-JG-16.2 was classified as a species of the genus Streptomyces; the 16S rRNA gene sequence comparison showing a 100% similarity with S. griseoruber NBRC12873 (AB184209).The strain was cultured on a rotary shaker (220 r.p.m.) at 28 1C for 5 days in 500-ml Erlenmeyer flasks (20 flasks) containing 50 ml of a production medium containing 2% rice starch (Rose brand, Cikampek, Indonesia), 2% glucose (Univar, Sydney, NSW, Australia), 2% soybean meal (J-Oil Mills, Tokyo, Japan), 0.5% yeast extract

Three novel antitrypanosomal alkaloids, named spoxazomicins A-C, were isolated by silica gel column chromatography and HPLC from the culture broth of a new endophytic actinomycete species, Streptosporangium oxazolinicum K07-0460 T . The structures of the spoxazomicins were elucidated by NMR and X-ray crystal analyses and shown to be new types of pyochelin family antibiotic. Spoxazomicin A showed potent and selective antitrypanosomal activity with an IC 50 value of 0.11 lg ml À1 in vitro without cytotoxicity against MRC-5 cells (IC 50 ¼27.8 lg ml À1 ).

In the course of screening for antimalarial agents, five tropolone compounds were isolated from the culture broth of Penicillium sp. FKI-4410. Two were known compounds, puberulic acid and stipitatic acid. Three were new analogs of puberulic acid, designated viticolins A-C. Among them, puberulic acid exhibited potent antimalarial inhibition, with IC 50 values of 0.01 lg ml À1 against chloroquine-sensitive and -resistant Plasmodium falciparum strains in vitro. Furthermore, puberulic acid showed weak cytotoxicity against human MRC-5 cells, with an IC 50 value of 57.2 lg ml À1 . The compound also demonstrated a therapeutic effect in vivo, which compared well against the currently used antimalarial drugs, and thus shows promise as a leading candidate for development into a new antimalarial compound.

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Two new isochromans, panowamycins A and B, were purified by solvent extraction, silica gel and octadecylsilyl silica gel (ODS) column chromatography followed by preparative HPLC, from a culture broth of Streptomyces sp. K07-0010, together with the known compounds NFAT-133, conglobatin, piericidin C series and dinactin. Structures of panowamycins were elucidated as new analogs of NFAT-133 by spectroscopic studies including various NMR experiments. Panowamycins A and B showed moderate antitrypanosomal activity, with IC 50 values of 0.40 and 3.30 lg ml -1 , respectively.