No abstract

In our search for fungal metabolites with antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), we have isolated three different setin antibiotics from several different fungi-the previously reported equisetin (2)1) and trichosetin (3),2) and a novel setin-like compound (1) from OSI 50185. Like the known setin antibiotics, cissetin (1) is active against several Grampositive organisms,2-5) but it is most notable for the atypical cis ring fusion in the octalin portion of the molecule.Cissetin (1) was isolated from OSI 50185 as a white foamy powder for which positive ion detection HR-FAB-MS suggested a molecular formula of C23H33NO4 [m/z, found 388.24893 (M+H)+, calcd 388.24892]. In contrast to reports of the NMR data for the setin class as extremely broad and ill-defined,1-5) 1 gave crisp, clean 1H and 13C NMR spectra in CDCl3 at ambient temperature (Table 1)

Peptides U 0400Isolation and Identification of the Icosalides -Cyclic Peptolides with Selective Antibiotic and Cytotoxic Activities. -The new cyclic depsipeptides (I) and (II) are extracted from two different fungal species found on dead ground wood in a tropical rain forest. Icosalide A1 (I) displays antimicrobial activity and icosalides A2 (IIa) and B (IIb) are cytotoxic to replicating MDCK cells. The unusual D-leucine moiety in (I) is an interesting deviation from the predomination of L-amino acids. -(BOROS*, C.; SMITH, C. J.; VASINA, Y.; CHE, Y.; DIX, A. B.; DARVEAUX, B.; PEARCE, C.; J. Antibiot. 59 (2006) 8, 486-494; MYCOsearch, OSI Pharm., Durham, NC 27707, USA; Eng.) -H. Haber 08-182

Fusion. -Cissetin (I) is isolated from the fungus OSI 50185 along with two known compounds. (I) is active against penicillin-resistant Streptococcus albicans. -(BOROS*, C.; DIX, A.; KATZ, B.; VASINA, Y.; PEARCE, C.; J. Antibiot. 56 (2003) 10, 862-865; Mycosynthetix Inc., Durham, NC 27707, USA; Eng.) -M. Bohle 13-194