Medicine and Health Sciences Commons^™

Modulation Of Antibacterial Activity And Cytotoxicity In Amphipathic Cyclic Peptide [R4w4] Using Histidine Substitution, Ryan Stueber

Pharmaceutical Sciences (MS) Theses

Antibiotics have been the gold standard frontline defense against bacterial infections for decades. At the same time, these infecting bacteria have continued to evolve to resist developed antibiotics in an almost endless cycle. As such, we aim to take an alternative approach utilizing antimicrobial peptides (AMPs) as a means to end this cycle. [R4W4] is among known AMPs that demonstrated antimicrobial activity against methicillin-resistant staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 2.67 μg/mL. This peptide had notably effective antimicrobial activity, especially relative to linear (R4W4). However, it displayed a concerning level of cytotoxicity; eliciting a human embryonic …

Amphiphilic Cell-Penetrating Peptides Containing Natural And Unnatural Amino Acids As Drug Delivery Tools And Antimicrobial Agents, David Salehi

Pharmaceutical Sciences (MS) Theses

Cell-penetrating peptides containing arginine as positively charged residues and tryptophan or diphenylalanine as hydrophobic residues were synthesized. The synthesis was accomplished through the Fmoc solid-phase peptide synthesis in the presence of HBTU and DIPEA. The side-chain protected linear peptides were cleaved from the resin and cyclized in the presence of DIC and HOAt in the solution phase overnight. MALDI-TOF mass spectrometry was used to characterize the peptides.

The cytotoxicity of the synthesized peptides was determined in CCRF-CEM (human, lymphoblast peripheral blood), and HEK-293 (human, embryonic epithelial kidney healthy) cells using the MTS assay. A concentration of 10 µM was found …