Pleurocidin
A winter-flounder antimicrobial peptide — broad-spectrum and membrane-disrupting, with anticancer, wound-healing and anti-colitis research. Research compounds, not drugs
Pleurocidin is a classic fish antimicrobial peptide, found in the skin mucus and gut of the winter flounder. It belongs to the piscidin family — short, cationic peptides that fold into amphipathic alpha-helices — and at twenty-five amino acids it is a well-characterised model peptide. Like other members it binds and disrupts microbial membranes, giving broad activity against bacteria and fungi. Over the last two decades pleurocidin has drawn interest well beyond antimicrobials: it is a promising anticancer peptide against breast carcinoma and leukemia, it modulates the immune system and the gut microbiome (easing experimental colitis in animals), and it supports wound healing. Because the free peptide is unstable in the body, much of the research now focuses on engineered forms — mirror-image D-amino-acid analogs, hybrid peptides and fibre-matrix wound dressings — and on the pharmacokinetic realities of turning a fast bacteria-killer into a usable therapeutic. Pleurocidins are research 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
Pleurocidins are flounder research peptides; none has been given to people as a treatment. The work is in bacteria, cultured cells and animals, often with engineered analogs or delivery systems, at experimental amounts that do not carry over to people.
Work out syringe units → · New to syringes? · All dosing data ↓ · Dose and vial tracker · Is this vial OK?
What is it?
Pleurocidin was discovered in 1997 in the skin secretions of the winter flounder, and it has since become one of the reference fish antimicrobial peptides. It is a member of the piscidin family — a twenty-five-residue linear, cationic peptide that is disordered in water but folds into an amphipathic alpha-helix on a membrane. Pleurocidin-like peptides are conserved across flatfish; a 2025 study identified a new one in the starry flounder, confirming the family's structural conservation and its role in fish innate immunity, where its gene is switched on by bacterial endotoxin.
Its core mechanism is membrane disruption: the cationic helix binds and permeabilises the microbial membrane, confirmed in flatfish pleurocidins by electron microscopy showing marked membrane damage. Pleurocidin is broadly active against Gram-positive and Gram-negative bacteria and against fungi. As with other antimicrobial peptides, however, turning this rapid killing into a systemic drug is hard: a 2026 study of mirror-image (D-amino-acid) pleurocidin analogs showed that stereochemistry strongly shapes how the peptide distributes in the body and how long effective levels last, and that fast killing in a test tube does not guarantee clearance of a lung infection in mice — a cautionary lesson for the whole field.
Pleurocidin's best-known second role is in cancer research. Reviews describe it and its analogs as selective anticancer peptides, cytotoxic to breast carcinoma and leukemia cells while relatively sparing healthy cells, acting through the same membrane-targeting chemistry that kills bacteria. Pleurocidin is also immunomodulatory: given rectally in a mouse model of ulcerative colitis, it eased symptoms and tissue damage, restored the gut barrier, calmed inflammatory signalling and rebalanced the gut microbiota — pointing to possible roles in inflammatory bowel disease beyond simple antimicrobial use.
Because the native peptide is fragile, delivery and engineering are central themes. Pleurocidin has been loaded into electrospun fibre matrices that release it to kill wound-associated pathogens such as Acinetobacter baumannii and Pseudomonas aeruginosa and that can act additively or synergistically with standard wound biocides, illustrating how formulation can rescue an unstable peptide for topical use. These are laboratory and animal studies, not treatments given to people.
Through all of this, pleurocidins remain research peptides. No published study has given a pleurocidin 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
Pleurocidin is a 25-residue linear cationic amphipathic alpha-helical winter-flounder (piscidin-family) antimicrobial peptide that binds and disrupts microbial membranes (broad-spectrum antibacterial, antifungal). It is also a selective anticancer peptide and an immunomodulator (easing experimental colitis), and is widely engineered and formulated for delivery.
Flounder/piscidin host defense
A 25-residue cationic amphipathic helix from winter-flounder skin mucus/intestine, in the piscidin family; conserved across flatfish and switched on by endotoxin (PMID 40379117).
Membrane disruption
Binds and permeabilises bacterial and fungal membranes (broad-spectrum), confirmed by electron microscopy; fast killing but delivery-limited systemically (PMIDs 37992909, 42663455).
Anticancer + immunomodulation
Selectively cytotoxic to breast-carcinoma and leukemia cells, and immunomodulatory — easing experimental colitis and rebalancing gut microbiota (PMIDs 38344173, 38422770).
Published Research
These are studies of pleurocidins read from their PubMed records on November 7, 2026: a pharmacokinetic study of mirror-image pleurocidin analogs in mice; a review and trend analysis of pleurocidin-like peptides; the discovery and antimicrobial mechanism of a new flatfish pleurocidin; an anti-colitis study in mice; a review of pleurocidin's anticancer potential; and a wound-matrix delivery study against wound pathogens. The evidence is in bacteria, cells and animals; pleurocidins have not been given to people as a treatment.
Stereochemistry shapes how a pleurocidin peptide behaves in the body (mice)
A mirror-image (D-amino-acid) pleurocidin analog killed priority bacterial pathogens within minutes in vitro, and its D-form distributed more favourably in the body (less renal and liver clearance) than the L-form; but given systemically it did not quickly clear lung infection in mice, though sustained exposure modulated the host immune response — showing that in-vitro potency alone does not predict systemic efficacy.
Review and trend analysis of pleurocidin-like peptides
A bibliometric review of two decades of pleurocidin research maps its biological activities, mechanisms, optimisation strategies and applications across aquaculture, food preservation and pharmaceuticals, and identifies computer-aided molecular design as an emerging trend for improving these peptides (a review).
A new flatfish pleurocidin from starry flounder
A novel pleurocidin gene (SF1) found in starry flounder encodes a 22-residue mature peptide whose expression in immune organs rose with endotoxin stimulation; structural modelling showed an amphipathic alpha-helix, and the peptide was active against Gram-positive and Gram-negative bacteria with electron microscopy confirming membrane disruption — establishing it as part of the fish's innate immunity (an in-vitro study).
Pleurocidin eases ulcerative colitis in mice
In a chemically induced mouse model of ulcerative colitis, pleurocidin relieved clinical symptoms and colon damage, normalised inflammatory and immune cytokines, restored tight-junction (gut-barrier) proteins, suppressed NF-kB and MAPK inflammatory signalling and rebalanced the gut microbiota toward beneficial bacteria — a preclinical anti-colitis result.
From antimicrobial to anticancer: pleurocidin and its derivatives
A review of pleurocidin's biology summarises evidence that pleurocidin and pleurocidin-derived peptides act as selective anticancer agents against breast carcinoma and leukemia through potent, cancer-cell-selective cytotoxicity, and surveys hybrid peptides and nanosystems, therapeutic potential, safety and current limits (a review).
Pleurocidin-loaded fibre matrices kill wound pathogens
Pleurocidin incorporated into electrospun polyvinyl-alcohol fibre matrices was released in amounts sufficient to kill wound-associated pathogens including Acinetobacter baumannii and Pseudomonas aeruginosa, retained activity after release, and acted additively or synergistically with standard wound biocides — a topical delivery study.
No Established Human Dose
Pleurocidins are flounder research peptides; none has been given to people as a treatment. The work is in bacteria, cultured cells and animals, often with engineered analogs or delivery systems, 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 42663455, PMID 38422770, PMID 37992909.
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 Pleurocidin 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 Pleurocidin 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 Pleurocidin, 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 Pleurocidin stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Pleurocidin. 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 short and delivery-limited in the body; stereochemistry and formulation strongly affect exposure. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Pleurocidin. Results reported in the studies are under Published Research.
Source: half-life: PMID 42663455.
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 a pleurocidin to people; As membrane-active peptides, cytotoxicity and hemolysis to host cells are the central safety concern, and systemic delivery is limited by instability and clearance (PMID 42663455) — research findings, not human data; Pleurocidin and its derivatives are cytotoxic to cancer cells by design (PMID 38344173); selectivity for tumour over healthy cells is an open research question; Material sold online as a 'pleurocidin' 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 Pleurocidin. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Pleurocidins 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 Pleurocidin (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 Pleurocidin 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 pleurocidin 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
Pleurocidins 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
Pleurocidins have no approved use and no label. These points reflect their research status.
Legal Status
Pleurocidins are flounder antimicrobial peptides used as research compounds; they are not drugs and are not approved in any country.
Frequently Asked Questions
?What is pleurocidin?
An antimicrobial peptide from the skin mucus of the winter flounder, a member of the piscidin family of fish antimicrobial peptides. It is a 25-amino-acid linear cationic amphipathic helix, first isolated in 1997 (PMID 38344173).
?How does it work?
It binds and disrupts microbial membranes, with broad-spectrum activity against bacteria and fungi; the same membrane-targeting chemistry also makes it selectively cytotoxic to some cancer cells (PMIDs 37992909, 38344173).
?What is it studied for?
As a broad-spectrum antimicrobial, a selective anticancer peptide (breast carcinoma, leukemia), an immunomodulator (easing experimental colitis), and a wound-healing agent — usually as engineered analogs or in delivery systems (PMIDs 38344173, 38422770, 37992909).
?Is it approved or available to buy?
No. Pleurocidins are not medicines, have no FDA application or label, and are approved nowhere. Material sold online as a pleurocidin is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [animal] Romanopulos J, et al. "Enantiomer-dependent biodistribution and exposure determine the in vivo behavior of a pleurocidin-derived antimicrobial peptide." mBio, 2026;17(10):e0171826. PMID: 42663455.
- [review] Fu Z, et al. "From winter flounder to multifunctional applications: A review of pleurocidin-like peptides via visualization and trend analysis." Microb Pathog, 2026;217:108594. PMID: 42202950.
- [mechanism] Choi MJ, et al. "Characterization and antimicrobial activity of a novel pleurocidin in starry flounder (Platichthys stellatus)." Fish Shellfish Immunol, 2025;163:110420. PMID: 40379117.
- [animal] Nong K, et al. "Effect of the Pseudopleuronectes americanus-derived Pleurocidin on DSS-induced Ulcerative colitis in mice and its preliminary molecular mechanisms." Int Immunopharmacol, 2024;130:111757. PMID: 38422770.
- [review] Piktel E, et al. "From antimicrobial to anticancer: unraveling the potential of pleurocidin and pleurocidin-derived peptides in the treatment of cancers." Front Pharmacol, 2024;15:1340029. PMID: 38344173.
- [mechanism] Ramos C, et al. "Fibrous matrices facilitate pleurocidin killing of wound associated bacterial pathogens." Eur J Pharm Sci, 2024;192:106648. PMID: 37992909.
- [other] Pleurocidin is an antimicrobial peptide from the skin mucus and intestine of the winter flounder (Pleuronectes/Pseudopleuronectes americanus), a member of the piscidin family of fish antimicrobial peptides. It was first isolated and characterised by Cole, Weis and Diamond (J Biol Chem, 1997); related pleurocidins occur across flatfish. Its structure and activities are described in the studies 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 pleurocidin peptides. They are flounder research antimicrobial/anticancer 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. Pleurocidin's winter-flounder origin and piscidin-family membership, its 25-residue cationic amphipathic helical structure, its membrane-disrupting broad-spectrum mechanism, its selective anticancer, immunomodulatory (anti-colitis) and wound-healing activities, and its engineered analogs and delivery systems are from the studies carded here; the discovery is Cole, Weis & Diamond (J Biol Chem, 1997). 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.