Reviewed by PeptideGuide Research TeamLast updated February 15, 2026

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Antimicrobial Peptides

Antimicrobial peptides (AMPs) represent a diverse class of naturally occurring and synthetic molecules that serve as the first line of defense against pathogenic microorganisms. These bioactive peptides demonstrate broad-spectrum activity against bacteria, fungi, viruses, and parasites through multiple mechanisms of action, making them invaluable tools in both research and therapeutic applications. Unlike conventional antibiotics that typically target specific cellular processes, antimicrobial peptides often disrupt microbial cell membranes, interfere with intracellular processes, or modulate host immune responses. This multi-target approach significantly reduces the likelihood of resistance development, addressing one of the most pressing challenges in modern medicine. The antimicrobial peptide category encompasses both host defense peptides naturally produced by various organisms and engineered variants optimized for specific applications. These peptides play crucial roles in innate immunity, wound healing, and maintaining microbial homeostasis in healthy tissues. Their unique properties, including rapid action, low toxicity to mammalian cells at therapeutic concentrations, and ability to synergize with conventional antimicrobials, make them promising candidates for treating antibiotic-resistant infections. Research applications include studying membrane biology, developing novel therapeutic strategies, and understanding host-pathogen interactions. The growing threat of antimicrobial resistance has intensified interest in these peptides as next-generation antimicrobial agents for clinical use.

Category Overview

The antimicrobial peptides in this category exhibit distinct mechanisms and target specificities. Nisin, a lantibiotic produced by Lactococcus lactis, primarily targets gram-positive bacteria by binding to lipid II and forming membrane pores, making it highly effective in food preservation. Cecropin A, derived from moth immune systems, demonstrates broad-spectrum activity through membrane permeabilization with minimal hemolytic activity. Magainin 2, originally isolated from frog skin, shows balanced activity against both bacteria and fungi while maintaining low mammalian cell toxicity. Polymyxin B represents a clinically used cyclic peptide with potent activity against gram-negative bacteria, particularly effective against multidrug-resistant strains, though with notable nephrotoxicity concerns. Defensin HNP-1, a human neutrophil-derived peptide, exhibits antimicrobial activity alongside immunomodulatory functions, playing dual roles in direct pathogen killing and immune system activation. Each peptide offers unique advantages: Nisin for food applications, Cecropin A for research requiring low toxicity, Magainin 2 for broad-spectrum studies, Polymyxin B for resistant gram-negative infections, and Defensin HNP-1 for immune-related research.

How to Choose

Selecting the appropriate antimicrobial peptide depends on your specific research objectives, target organisms, and experimental constraints. For studies focusing on gram-positive bacteria or food preservation applications, Nisin offers excellent specificity and established safety profiles. Researchers investigating broad-spectrum antimicrobial mechanisms with minimal cytotoxicity should consider Cecropin A or Magainin 2, both offering balanced activity profiles suitable for cell culture studies. When targeting gram-negative bacteria, particularly multidrug-resistant strains, Polymyxin B provides potent activity but requires careful consideration of potential toxicity in mammalian systems. For immunology research or studies examining host defense mechanisms, Defensin HNP-1 offers the advantage of combined antimicrobial and immunomodulatory activities. Consider peptide stability, solubility, and cost factors when making selections. Synthetic variants may offer improved stability and reproducibility compared to natural isolates. For initial screening studies, starting with well-characterized peptides like Magainin 2 or Cecropin A provides reliable baselines. Always evaluate peptide purity, storage requirements, and compatibility with your experimental conditions. Consider potential synergistic effects when combining peptides or using them alongside conventional antimicrobials.

All Antimicrobial Peptides (7)

Nisin

Lantibiotic

Generally Recognized As Safe (GRAS)

Nisin is a lantibiotic peptide primarily used as an antimicrobial agent in the food industry. It is effective in controlling spoilage and pathogenic bacteria, making it a valuable tool for food preservation. Nisin works by disrupting bacterial cell wall synthesis, leading to cell death, and is recognized as safe for consumption. Its applications extend beyond food preservation, as it is also explored for use in healthcare settings to control bacterial infections.

•Food preservation

Polymyxin B

Cyclic lipopeptide antibiotic

Approved

Polymyxin B is a cyclic lipopeptide antibiotic primarily used to treat serious Gram-negative bacterial infections. It functions by binding to the bacterial cell membrane, disrupting its integrity, and causing cell death. Due to its nephrotoxic and neurotoxic potential, its use is generally reserved for cases where other antibiotics are ineffective or contraindicated. Polymyxin B is administered intravenously or topically, depending on the infection site, and requires careful monitoring to mitigate potential side effects.

•Treatment of Gram-negative bacterial infections

Daptomycin

Lipopeptide antibiotic

Approved

Daptomycin is a lipopeptide antibiotic used primarily for the treatment of serious Gram-positive bacterial infections. It works by disrupting the bacterial cell membrane, leading to rapid depolarization and cell death. Daptomycin is particularly effective against resistant strains such as MRSA and is administered intravenously. Its use is generally reserved for severe infections due to its potency and the need for careful monitoring of side effects.

•Treatment of Gram-positive bacterial infections

Cecropin A

Antimicrobial peptide

Not Approved

Cecropin A is a potent antimicrobial peptide known for its ability to disrupt bacterial cell membranes, leading to the death of a wide range of bacteria. It is primarily used in research settings to explore new treatments for bacterial infections, particularly those resistant to conventional antibiotics. Its mechanism involves forming pores in bacterial membranes, which is effective against both Gram-negative and Gram-positive bacteria. Despite its promising antimicrobial properties, Cecropin A is currently not approved for clinical use and is available for research purposes only.

•Bacterial infections

Magainin 2

Antimicrobial Peptide

Not Approved

Magainin 2 is a potent antimicrobial peptide primarily used for research purposes. It is known for its ability to disrupt microbial cell membranes, leading to the lysis and death of bacteria and fungi. This peptide is particularly effective in infection control and wound healing applications, where it helps reduce microbial load and promote a healthier healing environment. Despite its promising properties, Magainin 2 is not yet approved for clinical use and remains a focus of ongoing research.

•Infection control

Defensin HNP-1

Alpha-defensin

Not Approved

Defensin HNP-1, also known as Human Neutrophil Peptide 1, is a potent antimicrobial peptide belonging to the alpha-defensin class. It is primarily used in research settings to study its effects on bacterial, fungal, and viral infections. HNP-1 functions by disrupting microbial cell membranes, leading to cell lysis, and also modulates immune responses by interacting with immune cells. Despite its promising antimicrobial properties, HNP-1 is not approved for clinical use and remains a subject of scientific investigation.

•Bacterial Infections

Cathelicidin

Antimicrobial peptide

Not Approved

Cathelicidin, also known as LL-37, is a multifunctional antimicrobial peptide primarily recognized for its ability to disrupt microbial membranes and modulate immune responses. It is part of the innate immune system and is involved in infection control and wound healing. Although not approved by the FDA, it is widely studied for its potential applications in treating infections and promoting tissue repair.

•Infection control