Iturin AL--a new long chain iturin a possessing an unusual high content of C16-beta-amino acids.

From a strain of Bacillus subtilis a new antifungal peptidolipid complex of the iturin group was isolated. This antibiotic complex contained six lipophilic beta-amino acids with 3-amino-14-methylpentanoic acid as the predominant component. Iturin AL contains: 2 D-Asp, 1 L-Asp, 1 L-Glu, 1 L-Pro, 1 L-Ser, 1 D-Tyr and a mixture of 2.9% iso-C14-beta-amino acid, 30.7% n-C14-beta-amino acid, 15% iso-C15-beta-amino acid, 9% anteiso-C15-beta-amino acid, 35.3% iso-C-16-beta-amino acid and 4.5% n-C16-beta-amino acid. The structures of the beta-amino acids were determined by combined GLC/MS. FAB mass spectroscopy revealed three M+H+ peaks (1,043, 1,057, 1,071). Iturin AL could be resolved into six components by HPLC whose structures confirm the high amount of long chain beta-amino acids.

Quantitative determination of O-(beta-hydroxyethyl)-rutosides in serum by high-performance liquid chromatography.

A procedure for the quantitative determination of O-hydroxyethylated rutosides by high-performance liquid chromatography is described, which can be used for the detection of these modified flavonoids in human serum. Serum samples are processed by the addition of acetone, which removes most of the proteins. After passing the supernatant through a microcolumn of Amberlite XAD-2 and washing with water, the hydroxyethylated rutosides are eluted with methanol. The eluate is concentrated in vacuo. The methanolic solution of the residue is chromatographed on RP-8 columns using UV and fluorescence detectors. The mono- to tetrahydroxyethylated constituents and their corresponding aglycones could be separated with a step gradient, starting with a solvent system of water-methanol-acetic acid (70:30:6) followed by a mixture of water-ethanol-acetic acid (70:30:6). Alternatively, the rutosides can be separated by a linear gradient of water-acetonitrile. An almost linear calibration curve and about 80% recovery are obtained. A detection limit of 1 mg/l is achieved. Pharmacokinetic studies in human volunteers are described.

Herbicolins--New peptide antibiotics from Erwinia herbicola.

Erwinia herbicols (strain A 111) produces two acylated peptide antibiotics herbicolins A and B. Isolation of herbicolins was performed by adsorption on a polystryrol adsorbent followed by elution with methanol. Further purification was achieved by gel filtration on Sephadex LH-20, counter-current distribution or by TLC. Herbicolin A was chemically characterized, containing 2 glycines, 1 L-threonine, 1 D-allo-threonine, 1 D-glutamic acid, 1 D-leucine, 1 L-agrinine and beta-hydroxy myristic acid. Herbicolins A and B are inactive against bacteria, but highly active against yeasts and filamentous fungi.