Temporin-SHa and Its Analogs as Potential Candidates for the Treatment of Helicobacter pylori

Abstract

Helicobacterpylori is one of the most prevalent pathogens colonizing 50% of the world’s population and causing gastritis and gastric cancer. Even with triple and quadruple antibiotic therapies, H. pylori shows increased prevalence of resistance to conventional antibiotics and treatment failure. Due to their pore-forming activity, antimicrobial peptides (AMP) are considered as a good alternative to conventional antibiotics, particularly in the case of resistant bacteria. In this study, temporin-SHa (a frog AMP) and its analogs obtained by Gly to Ala substitutions were tested against H. pylori. Results showed differences in the antibacterial activity and toxicity of the peptides in relation to the number and position of D-Ala substitution. Temporin-SHa and its analog NST1 were identified as the best molecules, both peptides being active on clinical resistant strains, killing 90–100% of bacteria in less than 1 h and showing low to no toxicity against human gastric cells and tissue. Importantly, the presence of gastric mucins did not prevent the antibacterial effect of temporin-SHa and NST1, NST1 being in addition resistant to pepsin. Taken together, our results demonstrated that temporin-SHa and its analog NST1 could be considered as potential candidates to treat H. pylori, particularly in the case of resistant strains.

Synthesis and Evaluation of the Antibacterial Activities of 13-Substituted Berberine Derivatives

“…Previous studies have shown that some berberine’s derivatives have the ability to cause membrane permeabilization [ 15 , 16 , 22 ]. For this reason, the effect of the compounds 15 , 16 , 24 and 25 on the bacterial membrane integrity was investigated ( Figure 4 ).…”

“…Membrane permeabilization by berberine derivatives was evaluated using the cell-impermeable DNA/RNA probe propidium iodide as previously explained [ 15 , 16 , 22 , 23 ]. Logarithmic growing bacterial suspensions were prepared from overnight bacterial suspension by 1 in 10 dilution.…”

Furan-Conjugated Tripeptides as Potent Antitumor Drugs

“…Doxorubicin was used as positive control. After 48 h medium was aspirated and the number of viable cells was colorimetrically measured as previously described [ 27 , 28 , 29 ]. Briefly, after exposure to increasing concentrations of conjugates or doxorubicin for 48 h, cell viability was measured using the standard MTT or resazurin assay.…”

Antioxidant Activity and Biocompatibility of Fructo-Polysaccharides Extracted from a Wild Species of Ornithogalum from Lebanon

“…The toxicity of the extracts on human cells was evaluated using resazurin assay, as previously described [ 23 , 24 ]. Human cells used were HaCaT (Creative Bioarray, Shirley, NY 11967, USA), HUVEC (ECACC, Sigma–Aldrich, Lyon, France), and IMR90 cells (ATCC ® CCL186) (ATCC, Molsheim CEDEX, France) corresponding to normal human epidermal keratinocytes, primary human umbilical vein endothelial cells, and normal human lung fibroblast, respectively.…”