Biomedical subjects

C E Ballard

Publications and source records attributed to C E Ballard.

3 recordsLinked to original sources

PubMed2002

Recent developments in depsipeptide research.

This review focuses on the major developments in depsipeptide research since 1995. Depsipeptides are bio-oligomers composed of hydroxy and amino acids linked by amide and ester bonds. Many depsipeptides show very promising biological activities, including anticancer, antibacterial, antiviral, antifungal, anti-inflammatory, and anti-clotting or anti-antherogenic properties. In this report depsipeptides exhibiting these properties are discussed. Their isolation, structural determination, and notable structural features are discussed, but their biological properties and therapeutic potentials are emphasized. Depsipeptides have shown the greatest therapeutic potential as anticancer agents. Four depsipeptides have entered clinical trials for cancer treatment. Among the antiviral compounds discovered, the callipeltins and the quinoxapeptins are particularly promising due to their inhibitory activities against HIV. These compounds have the potential to be developed as anti-AIDS drugs or to serve as lead compounds for the discovery of structurally related anti-AIDS compounds. Antifungal compounds, such as the jaspamides, may lead to therapies against many of the opportunistic infections that accompany AIDS. Anti-inflammatory compounds such as SCH217048 act as neurokinin antagonists and may lead to anti-inflammatory treatments. Some depsipeptides such as micropeptins and A90720A have been found to be effective plasmin inhibitors, which have implications as treatments for cardiovascular diseases. Compounds such as SCH58149 help control the levels of HDL and LDL.

Anti-Inflammatory Agents↗

PubMed2000

A facilitated cyclic ether formation and its potential application in solid-phase peptide and organic synthesis.

A "trimethyl lock" system has been known to facilitate lactonization reactions through what has been termed a stereopopulation control mechanism. We have found that a similar trimethyl lock system can also facilitate cyclic ether formation with the concomitant release of a carboxylic acid in the presence of anhydrous tetrabutylammonium fluoride. To study this base-mediated trimethyl lock-facilitated cyclic ether formation, we synthesized fifteen model compounds. All model compounds underwent base-mediated cyclic ether formation in high yields at 0 degree C to room temperature (r.t.) with the concomitant release of the attached carboxylate. Such a system potentially could be used for the development of a two-dimensional linker for solid phase peptide and organic synthesis.

Carboxylic Acids↗

PubMed1999

Prodrug approaches to the improved delivery of peptide drugs.

Undesirable pharmaceutical and biopharmaceutical properties, which include low water solubility, poor stability, and low permeability through biological membrane barriers, often hinder the clinical development of biologically active peptides. Finding solutions to these problems is a contemporary issue in developing clinically the vast number of biologically active peptides as drugs. In recent years, significant progress has been made in developing prodrug approaches for the improvement of the water solubility, stability, and membrane permeability of peptides. For improving water solubility, the focus has been on the bioreversible introduction of ionizable functional groups to peptides, which helps to increase the polarity and thus water solubility of the peptide drugs. For improving stability, efforts have focused on stabilizing peptides against exopeptidase-mediated hydrolysis by bioreversibly masking the terminal carboxyl and/or amino groups. For improving permeability through biological barriers, recent efforts have focused on both improving the lipophilicity of a peptide in order to facilitate its passive permeation through biological membranes and conjugation of a peptide to a carrier which allows for the active transport of the peptide-carrier conjugate. Many of the prodrug systems developed recently have the potential to be used clinically for the delivery of peptide drugs to the desired site of action.

Animals↗