Rajiv Dahiya
President, Association of Pharmacy Professionals (APP), India
Title: Complex cyclic oligopeptides: Synthesis and biological properties
Biography
Biography: Rajiv Dahiya
Abstract
Natural products are the active components not only of most traditional medicines but also many modern medicines. They have pharmacological or biological activity that can be of therapeutic benefit in treating disorders. Some current medicines are obtained directly from natural sources but other medicines are developed from the natural product lead originally obtained from the natural source. Among wide range of natural products, complex cyclic oligopeptides peptides are of special interest for their enhanced stability and pharmacologic properties. Due to their limited conformational flexibility, cyclic peptides with C-to-N-terminal peptide bond and a disulfide bridge can confer high target binding affinity and resistance to proteolytic enzymes. Peptides and proteins are attractive initial leads for the rational design of bioactive molecules. Several natural cyclic peptides have recently emerged as templates for drug design due to their resistance to chemical or enzymatic hydrolysis and high selectivity to receptors. Further, bicyclic peptides can bind with high affinity and selectivity to protein targets, making this format attractive for biotechnological and medicinal applications. The good binding properties are based to a large extent on the limited conformational flexibility of the two connected peptide rings. On the other hand, Host Defense Peptides (HDPs), small cationic peptides, play a vital role in innate immunity response and immuno-modulatory stimulation. Antimicrobial Peptides (AMPs) like β-defensins and cathelicidin, are involved in the defence against pathogenic organisms, e.g., the antimicrobial activity of saliva largely depends on histidine-rich AMPs (histatins). These complex cyclic congeners being isolated from higher plants and marine resources, possess modified amino acid residues like DHHA, ADHA, AHOA, AHMP and exhibit their pharmacological properties through binding to corresponding enzymes which allow cyclic oligopeptides to act as therapeutic agents in resistant world.