Aurein
A family of tiny Australian bell-frog antimicrobial peptides — membrane-disrupting, with antibiotic and anticancer activity, and a favourite short design scaffold. Research compounds, not drugs
Aureins are short antimicrobial peptides from the skin of Australian bell frogs — the Green and Golden Bell Frog and the Southern Bell Frog. The best-studied member, aurein 1.2, is only thirteen amino acids long, which makes it one of the shortest frog peptides known to carry both antibiotic and anticancer activity. Like other membrane-active peptides, aureins are cationic, amphipathic alpha-helices: they fold so that charged and water-liking residues line up on one face and greasy residues on the other, letting them bind and perturb the membranes of bacteria and some cancer cells. The frogs make more than a dozen aureins, grouped by sequence into families 1 through 5, of which the shorter aureins 1-3 are the membrane-active ones. Because aurein 1.2 is so small and well characterised, it has become a standard model for studying how short peptides interact with membranes and a popular starting point for engineering new antimicrobial and anticancer designs. Aureins are research antimicrobial peptides; they are not approved medicines and have not been given to people as a treatment.
No established human dose Details ↓
Recommended Dosing
No established human dose
Aureins are frog-skin research peptides; none has been given to people as a treatment. The work is in model membranes, bacteria and cultured cells, often with engineered analogs, at experimental amounts that do not carry over to people.
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What is it?
Frog skin is one of nature's richest sources of antimicrobial peptides, and the aureins are the contribution of two Australian bell frogs — the Green and Golden Bell Frog (Litoria aurea) and the Southern Bell Frog (Litoria raniformis). When Rozek and colleagues analysed the secretion from the frogs' granular dorsal glands around 2000, they found roughly sixteen-to-seventeen related peptides, which they grouped by sequence into aureins 1 through 5. Most of the active members are very short: aurein 1.2 (GLFDIIKKIAESF-NH2) is just thirteen residues and is amidated at its C-terminus, making it among the smallest anuran peptides reported to have both antibiotic and anticancer activity.
Aureins are cationic and amphipathic. In a membrane-like environment aurein 1.2 folds into a single amphipathic alpha-helix with distinct water-liking and greasy faces, which is what lets it bind the surface of a microbial membrane. The longer aureins 4 and 5 lack this activity, so the family doubles as a natural structure-activity series. Their small size and well-defined structure have made aurein 1.2 a standard model peptide for biophysics: neutron-scattering work showed it sits mainly in the lipid head-group region and can thin, stiffen and reorganise a membrane — even driving charged lipids to segregate into domains — without necessarily punching classic pores, one explanation for how such a short peptide damages membranes at low concentrations.
The membrane mechanism has been dissected residue by residue. Swapping the two phenylalanines of aurein 1.2 showed that the N-terminal phenylalanine drives membrane binding while the C-terminal one controls selectivity for bacterial over mammalian membranes, and that cholesterol protects mammalian-type membranes from disruption. Coarse-grained simulations of aurein 1.2 and engineered variants have mapped how sequence and charge change membrane insertion and the stability of peptide assemblies, reinforcing the picture of a surface-active, selectivity-tunable peptide.
Because aurein 1.2 is short and modular, it is a favourite scaffold for design. Inserting extra cell-penetrating segments produced analogs with several-fold stronger antibacterial, antibiofilm and anti-proliferation activity, and alignment-guided redesign yielded aurein-derived peptides with improved activity against Gram-negative bacteria while researchers tracked their toxicity on normal human skin cells. Across this work the recurring challenge is the one shared by all membrane-active peptides: getting selective potency against microbes or tumour cells without harming host cells (hemolysis and cytotoxicity).
Through all of it, aureins remain research antimicrobial peptides. No published study has given an aurein to people as a treatment, none is approved anywhere, and material sold online under these names is an unregulated research chemical. Nothing here is a dose or a therapy; this page records what the published science says.
Mechanism of Action
Aureins are short cationic amphipathic alpha-helical frog-skin antimicrobial peptides that work by binding and disrupting microbial (and some cancer-cell) membranes. Aurein 1.2 acts largely at the membrane surface, thinning and reorganising the bilayer rather than only forming pores, and its short scaffold is widely engineered for potency and selectivity.
Bell-frog host defense
Short cationic amphipathic helices secreted by the dorsal skin glands of Litoria aurea and L. raniformis; a family of ~16-17 members grouped aureins 1-5 (PMID 10951191).
Membrane disruption
Bind the microbial membrane surface and thin, stiffen and reorganise the bilayer — segregating lipids and permeabilising it, not always via classic pores (PMIDs 37082600, 42734682).
Selectivity and engineering
Phenylalanine residues set binding and bacterial-vs-mammalian selectivity; analogs with added penetrating regions gain antibacterial, antibiofilm and anti-proliferation potency (PMIDs 41556696, 36830322).
Published Research
These are studies of aureins read from their PubMed records on November 7, 2026: the discovery and solution structure of aurein 1.2; residue-level and biophysical dissection of how aurein 1.2 binds and disrupts membranes (phenylalanine mutants, neutron scattering, coarse-grained simulation); and engineering of aurein-derived analogs for stronger or broader activity while tracking host-cell toxicity. The evidence is in model membranes, bacteria and cells; aureins have not been given to people as a treatment.
Discovery and solution structure of aurein 1.2 (Litoria bell frogs)
Sixteen-to-seventeen aurein peptides were isolated from the dorsal-gland secretions of Litoria aurea and Litoria raniformis and grouped as aureins 1-5; thirteen showed wide-spectrum antibiotic and anticancer activity. Aurein 1.2 (GLFDIIKKIAESF-NH2), the shortest, was shown by NMR to be an amphipathic alpha-helix with defined hydrophilic and hydrophobic faces, while aureins 4-5 were inactive — the founding structure-activity description of the family.
Phenylalanine residues govern how aurein 1.2 disrupts membranes
Comparing aurein 1.2 with alanine-substituted versions by fluorescence correlation spectroscopy showed the N-terminal phenylalanine drives membrane binding and overall activity while the C-terminal phenylalanine controls selectivity for bacterial over mammalian membranes; the wild-type selectively disrupted bacteria-mimicking membranes, and cholesterol protected mammalian-type membranes — a residue-level mechanism study.
Membrane interactions and pore stability of aurein 1.2 (simulation)
Coarse-grained molecular-dynamics simulations compared aurein 1.2 with an analog in model bacterial- and eukaryotic-like membranes; sequence and charge differences changed how deeply the peptides inserted and how stable their pre-formed pore assemblies were, with aurein 1.2 pores persisting longer in bacterial-like membranes — a computational mechanism study.
How aurein 1.2 modifies charged lipid bilayers (neutron scattering)
Neutron membrane diffraction and spin-echo spectroscopy showed aurein 1.2 sits mainly in the lipid head-group region without deep penetration, yet reduces membrane elasticity, slows lipid motion and drives lateral segregation of charged lipids — evidence that a short peptide can damage membranes at low concentration without forming classic pores (a biophysical study).
Aurein 1.2 analogs with added cell-penetrating regions
Inserting extra membrane-penetrating segments into aurein 1.2 produced analogs with several-fold stronger antimicrobial, antibiofilm and anti-proliferation activity and improved selectivity versus the parent peptide, showing how the short aurein scaffold can be re-engineered into more potent, broader-spectrum candidates (an in-vitro design study).
Alignment-designed aurein-derived peptides and their human-cell toxicity
Two aurein-derived peptides designed with alignment-based and machine-learning methods had improved activity against Gram-negative bacteria (E. coli, P. aeruginosa, B. subtilis) relative to natural aurein 1.2, and one was notably less toxic to normal human skin cells — illustrating the family's use as a design template and the central host-toxicity trade-off (an in-vitro study).
No Established Human Dose
Aureins are frog-skin research peptides; none has been given to people as a treatment. The work is in model membranes, bacteria and cultured cells, often with engineered analogs, at experimental amounts that do not carry over to people. No regulator has approved any dose, and no published human dose exists, so no amount is printed here.
What this rests on: PMID 10951191, PMID 36830322, PMID 30593676.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Aurein is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
Unknown: no human dose of Aurein has been established (see No Established Human Dose below), so there is no amount to work out. The reconstitution calculator does the arithmetic for any vial, water and dose.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Aurein, before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Aurein stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Aurein. What the human studies gave and how is set out under No Established Human Dose.
What to expect, and when
How long it stays in the body: a half-life of not established for humans; short cationic/amphipathic peptides subject to proteolysis. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Aurein. Results reported in the studies are under Published Research.
Source: half-life: PMID 36830322.
Side effects, and when to stop or get help
From the Side Effects section: No human adverse-event data exist: no published study has administered an aurein to people; As membrane-active peptides, hemolysis and cytotoxicity to host cells are the central safety concern; aurein-derived design work explicitly tracks toxicity on normal human cells (PMID 30593676) — a design issue, not human data; Aurein 1.2 and derivatives are active against some cancer cells (PMID 36830322); selectivity for target over healthy cells is an open research question; Material sold online as an 'aurein' is an unregulated research chemical of unverified content. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Aurein. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Aureins are research peptides that have not been given to people as drugs, so there is no human safety profile; the points below reflect that research status and their biology”).
Interactions
Unknown: a PubMed search for human interaction studies of Aurein (reviewed 2026-11-07) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Aurein products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Research Chemical (Not drugs: Drugs@FDA and the openFDA label endpoint hold no record, and FDA GSRS and ChEMBL hold no approved-drug record for aurein peptides (searched November 7, 2026)). Sport: Not on the 2026 List.
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
Aureins are research peptides that have not been given to people as drugs, so there is no human safety profile; the points below reflect that research status and their biology.
Contraindications & Cautions
Aureins have no approved use and no label. These points reflect their research status.
Legal Status
Aureins are bell-frog-skin antimicrobial peptides used as research compounds; they are not drugs and are not approved in any country.
Frequently Asked Questions
?What are aureins?
A family of short antimicrobial peptides from the skin of the Australian Green and Golden Bell Frog (Litoria aurea) and Southern Bell Frog (L. raniformis). Aurein 1.2 is only 13 amino acids — among the shortest frog peptides with both antibiotic and anticancer activity (PMID 10951191).
?How do they work?
They are cationic, amphipathic helices that bind and disrupt microbial membranes; aurein 1.2 acts largely at the membrane surface, thinning and reorganising the bilayer rather than only forming pores (PMID 37082600).
?What are they studied for?
As antibacterial and anticancer leads, as a standard model peptide for membrane biophysics, and as a short scaffold for engineering more potent or selective analogs (PMIDs 36830322, 30593676).
?Are they approved or available to buy?
No. Aureins are not medicines, have no FDA application or label, and are approved nowhere. Material sold online as an aurein is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [mechanism] Rozek T, et al. "The antibiotic and anticancer active aurein peptides from the Australian Bell Frogs Litoria aurea and Litoria raniformis the solution structure of aurein 1.2." Eur J Biochem, 2000;267(17):5330-41. PMID: 10951191.
- [mechanism] Saadatmand ZN, et al. "Synergistic Effect of Phenylalanine Residues Governs the Mechanism of Membrane Disrupting Action of Aurein 1.2." J Med Chem, 2026;69(3):2712-2724. PMID: 41556696.
- [mechanism] Ansarihaghi R. "Membrane interactions and pore stability of aurein 1.2 and LLAA in single- and multi-peptide systems revealed by coarse-grained molecular dynamics simulations." J Mol Model, 2026;32(10). PMID: 42734682.
- [mechanism] Qian S, et al. "Interaction of a short antimicrobial peptide on charged lipid bilayer: A case study on aurein 1.2 peptide." BBA Adv, 2022;2:100045. PMID: 37082600.
- [mechanism] Liao F, et al. "A Novel Strategy for the Design of Aurein 1.2 Analogs with Enhanced Bioactivities by Conjunction of Cell-Penetrating Regions." Antibiotics (Basel), 2023;12(2). PMID: 36830322.
- [mechanism] Madanchi H, et al. "Alignment-based design and synthesis of new antimicrobial Aurein-derived peptides with improved activity against Gram-negative bacteria and evaluation of their toxicity on human cells." Drug Dev Res, 2019;80(1):162-170. PMID: 30593676.
- [other] Aureins are a family of short antimicrobial peptides from the granular dorsal-gland skin secretions of the Australian Green and Golden Bell Frog (Litoria aurea) and the Southern Bell Frog (Litoria raniformis). They were isolated, sequenced and structurally characterised by Rozek and colleagues (Eur J Biochem, 2000), who found roughly sixteen-to-seventeen members grouped as aureins 1-5; the discovery and the solution structure of aurein 1.2 are in the study carded on this page (read November 7, 2026).
- [other] US FDA, Drugs@FDA and the openFDA label endpoint, searched November 7, 2026: no application and no label record for aurein peptides. They are frog-skin research antimicrobial peptides, not drugs; FDA GSRS and ChEMBL hold no approved-drug record for them.
Sources & Citations
The six studies carded above were read from their PubMed records on November 7, 2026. The aurein family's bell-frog-skin origin (Litoria aurea and L. raniformis), its grouping into aureins 1-5, the short amphipathic alpha-helical structure of aurein 1.2, its surface-active membrane-disrupting mechanism, and its anticancer and engineered-analog activity are from the studies carded here; the discovery and structure are Rozek et al. (Eur J Biochem, 2000). The absence of US approval or a drug record from Drugs@FDA, openFDA, FDA GSRS and ChEMBL was checked the same day. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.