Utilizing the solid phase peptide synthesis protocol, we have designed and prepared a novel dipeptide library containing (S)‐5‐oxopyrrolidine‐2‐carboxylic acid moiety. All the newly synthesized dipeptides were characterized by spectroscopic techniques as well as elemental analysis. Furthermore, the in vitro antimicrobial activities of the synthesized dipeptide conjugates were evaluated. Two Gram‐positive (Streptococcus pyogenes and Staphylococcus aureus) and two Gram‐negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were utilized to evaluate the antibacterial activity of the screened derivatives. In contrast to the standard drug Ampicillin, the targeted derivatives exhibited good antibacterial activity. Additionally, two fungi (Candida albicans and Aspergillus niger) were used to evaluate the antifungal activity of the target dipeptides. The targeted derivatives also exhibited good antifungal activity compared to the standard drug Nystatin. In continuous, the molecular docking study of the targeted derivatives was also carried out, which revealed that the dipeptide analogs showed encouraging binding interaction networks with Escherichia coli DNA gyrase B and lanosterol‐14 alpha demethylase resulting in antibacterial and antifungal activities, respectively. Such synthesis, biological evolution, and molecular docking study of peptide derivatives with oxopyrrolidine conjugates open the door for the future development of new therapeutics containing heterocycle and peptide hybrids with potency as antimicrobial agents.

A new series of cyclic antimicrobial peptides (AMPs) containing D/L-α-amino acids have been designed and characterized by spectroscopic techniques. Newly synthesized cyclic peptides were tested for antibacterial and antifungal activities in the hopes of discovering novel clues that may be used to create effective anti-microbial medicine. Those cyclic AMPs demonstrated good antibacterial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and that was comparable to reference drug Imipenem, as well as good antifungal activity against microbial strains Aspergillus Flavus, Candida Albicans and Candida GlabarataI that was comparable to reference drug Miconazole. In continuous, molecular docking study of the targeted cyclic peptides revealed that they exhibited promising binding interaction networks with DNA gyrase and lanosterol-14 alpha demethylase, which showed the correlation between biologic activity and docking score of the synthesized analogs.

A new series of dipeptide derivatives with 5-chloro-thiophene-2-carboxylic acid conjugates have been designed and synthesized using solid-phase peptide synthesis. The synthesized dipeptide derivatives were characterized by using spectroscopic tools, like 1H and 13C NMR, IR, and mass and elemental analysis. Additionally, the obtained target dipeptide derivatives were evaluated for in vitro antimicrobial activity. The antibacterial activity of the target compounds was evaluated against four bacteria (two Gram-positive; Streptococcus pyogenes and Staphylococcus aureus, two Gram-negative; Escherichia coli and Pseudomonas aeruginosa). The screened analogs showed good antibacterial activity. Noteworthily, among them, Thiophene-Tyr-Arg-OH derivative exhibited excellent activity against Escherichia coli (MIC=15 µg/mL) as compared to standard drug ampicillin. The antifungal activity was evaluated against two fungi (Aspergillus niger and Candida albicans). The screened analogs also showed good antifungal activity.