ABSTRACT
The condensation of the carboxyl function of teicoplanin A2 (CTA) and its acidic hydrolysis pseudoaglycons (TB, TC) and aglycon (TD) with amines carrying various functional groups and chains produced amide derivatives with different isoelectric points and lipophilicities. Amide formation did not affect the ability of these compounds to bind to Ac2-L-Lys-D-Ala-D-Ala, a model for the natural peptide binding site in bacterial cell walls. The antimicrobial activities of teicoplanin amides were found to depend mostly on their ionic and lipophilic character and on the type and number of sugars present. Positively charged amides were generally more in vitro active than the respective unmodified antibiotics against Gram-positive organisms. In particular, most basic amides of CTA were markedly more active than teicoplanin against coagulase-negative staphylococci. A few amides of TC and most of those of TD also showed a certain activity against Gram-negative bacteria. In experimental Streptococcus pyogenes septicemia in the mouse, some basic amides were more active than the parent teicoplanins when administered subcutaneously. Some of those of CTA were also slightly more effective than teicoplanin by oral route.
Subject(s)
Amides/pharmacology , Anti-Bacterial Agents , Amides/chemical synthesis , Animals , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/metabolism , Chemical Phenomena , Chemistry , Chromatography, High Pressure Liquid , Glycopeptides/chemical synthesis , Glycopeptides/metabolism , Glycopeptides/pharmacology , Isoelectric Focusing , Mice , Peptides/metabolism , Streptococcal Infections/drug therapy , Structure-Activity Relationship , TeicoplaninABSTRACT
Mono- and didechlorinated derivatives of the antibiotic teicoplanin, its pseudoaglycones and aglycone, and of one amide and ester of deglucoteicoplanin were prepared under selective reductive conditions. The selectivity and rate of dehalogenation were studied and compared to those of vancomycin and deglucovancomycin. The influence of the chlorine substituents on the mechanism of action and antibacterial activity of teicoplanin antibiotics was also investigated.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Animals , Chlorine , Glycopeptides/chemical synthesis , Glycopeptides/pharmacology , Magnetic Resonance Spectroscopy , Mass Spectrometry , Mice , Microbial Sensitivity Tests , Molecular Structure , Peptides/metabolism , Sepsis/drug therapy , Streptococcal Infections/drug therapy , Streptococcus pyogenes/drug effects , Structure-Activity Relationship , TeicoplaninABSTRACT
L-Alanosine [3-(hydroxynitrosoamino)-L-alanine] is an antitumor antibiotic that at the present is undergoing phase II clinical trials. Its mode of action as well as its metabolism has been extensively studied, and the metabolite N-[(5-amino-1-beta-D-ribofuranosyl-1H-imidazol-4-yl)carbonyl]-3- (hydroxynitrosoamino)-L-alanine ribonucleotide (L-alanosine AICOR) proved to be an extremely potent inhibitor of de novo purine biosynthesis and is thus primarily responsible for the antitumor activity of the drug. The synthesis of the corresponding ribonucleoside, i.e., N-[(5-amino-1-beta-D-ribofuranosyl-1H-imidazol-4-yl)carbonyl]-3- (hydroxynitrosamino)-L-alanine ribonucleoside (L-alanosine AICO ribonucleoside), was accomplished by condensation of a suitably protected derivative of L-alanosine with N-succinimidyl-5-amino-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-1H-im idazole-4-carboxylate followed by the removal of the protective groups. The biological activity of L-alanosine AICO ribonucleoside was tested in vitro on whole tumor cells and on the isolated enzyme adenylosuccinate synthetase and in vivo on murine experimental leukemia. The compound was found to be inactive in these tests.
Subject(s)
Antibiotics, Antineoplastic/chemical synthesis , Ribonucleotides/chemical synthesis , Cell Division/drug effects , Cell Line , Cell Survival/drug effects , DNA Replication/drug effects , Humans , Indicators and Reagents , Leukemia, Myeloid, Acute , Magnetic Resonance Spectroscopy , Ribonucleotides/toxicity , Spectrophotometry, InfraredABSTRACT
Basic hydrolyses carried out on the glycopeptide antibiotic teicoplanin or its acidic hydrolysis products give rise to epimeric species which retain little antibiotic activity. The detailed structure of a sample epimer has been determined using 1H NMR spectroscopy.
Subject(s)
Anti-Bacterial Agents , Glycopeptides , Hydrolysis , Isomerism , Magnetic Resonance Spectroscopy , Molecular Conformation , TeicoplaninABSTRACT
Teicoplanin is an antibiotic complex consisting of five closely related factors, T-A2-1, 2, 3, 4 and 5 and a more polar factor, T-A3-1. By controlled acid hydrolysis the complex is transformed into pseudoaglycones and finally into a single aglycone with consecutive removal of three sugar units. Quantitative determination of sugars obtained by degradative reactions and NMR/LC-MS studies on suitable derivatives confirmed that all the components carry one N-acyl-D-glucosamine and that at least two of them are characterized by N-decanoyl and N-undecanoyl chains on the D-glucosamine unit. The hydrolysis products still possess in vitro and in vivo activity.
