Melittin

Melittin | Bee Venom Peptide | PLA2 Activator | Anti-tumor Research | Science-Peptide

【Properties】White or off-white powder
【Purity】≥95%
【Package】5mg, 10mg
【Storage】2-8℃, Storage -20℃, sealed storage
【More Information】Peptide price, sequence information, chemical structure, molecular weight, scientific research literature, please email inquiry

Let's talk about Melittin (bee venom peptide, CAS 20449-79-0). You'll find this guy as the main ingredient in bee venom – seriously, it makes up 40-60% of the venom's dry weight. This busy peptide works as a PLA2 activator. It wakes up the low-molecular-weight PLA2 but leaves the high-molecular-weight one alone. Good manners, right?

Melittin is a cationic amphiphilic linear α-helical peptide. That's a mouthful, but here's what it means: it has 26 amino acids, and it's got a neat trick. Its N-terminal side hates water – that's the hydrophobic part. Its C-terminal side, loaded with positive charges, loves water – that's hydrophilic. Together, they form a helix-hinge-helix shape, sort of like a bent rod. And thanks to that structure, Melittin is pretty tough on cancer cells. For example, against A2780CR and A2780 cells, its IC₅₀ values sit at 4.5 and 6.8 μg/mL. Not bad at all.

So how does it work? This peptide slides onto cell membranes using electrostatic pull. Once there, it punches holes across the membrane – yes, really – and messes up the membrane's structure. At the same time, it cozies up to phospholipase A2 (PLA2) and pushes it toward its substrate. Meanwhile, Melittin raises calcium levels inside the cell. That little change encourages sPLA2 to grab onto membrane phospholipids tighter and work faster.

One more thing – and this is important. This peptide only activates low-molecular-weight PLA2. High-molecular-weight PLA2? Not touched. Why the difference? Because low-molecular-weight PLA2 is just more sensitive to how the membrane curves and what lipids are around. Melittin seems to know exactly which button to press. In the end, the combination of membrane damage, calcium chaos, and PLA2 activation is what gives Melittin its multi-targeted powers.

1. Anti-tumor research
Melittin is honestly one of the best natural peptides you'll find for fighting tumors. Researchers have seen it work against all sorts of cancer cell lines – gastric, breast, ovarian, liver, prostate, cervical, lung. You name it. It slows down cell growth, triggers apoptosis, and sometimes even causes direct necrosis.
Let's take colorectal cancer as an example. Back in 2024, Yang and his team published a study in the International Journal of Molecular Sciences. They found that this peptide causes a sudden burst of mitochondrial ROS. That drops the mitochondrial membrane potential (ΔΨm), lowers Bcl-2 levels, and raises Bax levels. One thing leads to another, and soon cytochrome C gets released – and that fires up the apoptotic program.
But that's not all. Melittin also hits the brakes on cell migration, invasion, and new blood vessel growth. It does this by turning down MMP expression and tweaking EMT markers. And guess what? Its anti-metastatic effects were confirmed in a real mouse lung metastasis model. In non-small cell lung cancer, this compound works as a radiosensitizer. It messes up the DNA damage repair system and gently nudges cancer cells toward apoptosis – a fresh angle for improving radiotherapy results.
In T-cell acute lymphoblastic leukemia, Melittin triggers apoptosis, drops mitochondrial membrane potential, boosts ROS production, and stalls the cell cycle. In HL-60 acute promyelocytic leukemia cells, this peptide cuts down cell viability in a dose- and time-dependent way. You can see clear drops at 24 and 48 hours after treatment. Plus, it stops EGF-induced cell invasion by blocking the PI3K/Akt/mTOR pathway – especially in breast cancer cells.

2. Antimicrobial, anti-biofilm, and anti-quorum sensing studies
A 2024 study in Molecules put Melittin in the spotlight as a triple-action antimicrobial agent. And the results were pretty striking. This peptide stops bacterial growth in a concentration-dependent way. Scanning electron microscopy confirmed it dramatically changes bacterial shape – not something you see every day.
Then they used confocal laser scanning microscopy and found that Melittin boosts bacterial membrane permeability and cranks up intracellular ROS production. Crystal violet staining showed it doesn't just stop biofilms from forming – it also clears out mature ones. Pretty impressive, right? Molecular docking and dynamics analyses later confirmed that this compound works its anti-quorum-sensing magic by forming hydrogen bonds with the LasR receptor. That shuts down nasty virulence factors like pyocyanin, elastase, and rhamnolipids.

3. Anti-inflammatory and rheumatoid arthritis research
In a 2024 review published in Frontiers in Immunology, Pareek and his colleagues highlighted something interesting. Melittin – which makes up 50-60% of bee venom – significantly dials down NF-κB activity. It also puts a leash on MMP-1 and MMP-8 and reduces TNF-α production. All of that helps protect type II collagen from breaking down. So yes, it shows real cartilage-protecting benefits in rheumatoid arthritis.
On top of that, this peptide lowers inflammatory target gene expression. How? By interfering with the sulfhydryl reaction between IκB kinase and the NF-κB p50 subunit. A pretty clever move, if you ask me.

4. Antiviral and other applications
A 2024 review by Zhang and colleagues in Frontiers in Immunology summed up Melittin's antiviral, antitumor, and anti-inflammatory talents. The authors pointed out that this peptide could be useful for diseases that still don't have specific clinical drugs. And it might even boost the effectiveness of some first-line treatments. Oh, and one more thing – Melittin has also been reported to have antidiabetic activity. Quite the overachiever, don't you think?

5. Nanodelivery systems and toxicity avoidance strategies
Let's be honest for a second. Melittin's journey to the clinic has been rocky. The main problems? Hemolytic activity and off-target toxicity. But science is pushing back.
A 2025 review by Rizkallah and colleagues in Pharmaceutics walked through all the latest delivery systems for Melittin – liposomes, polymeric nanoparticles, dendrimers, micelles, inorganic nanosystems. You name it. These clever nanocarriers help with tumor targeting, cut down side effects, improve stability, and tackle multidrug resistance. They also play nicely with other therapies – chemotherapy, immunotherapy, photothermal therapy, and radiotherapy.
Here's a concrete example. HSA-coated polymeric nanoparticles (PMH NPs) made from PLLA-Cys-Melittin are taken up specifically by SPARC-positive cells. They show way less hemolysis and put the brakes on tumor growth in living models. Similarly, PEGylated PLGA nanoparticles loaded with this peptide also reduce hemolysis and boost therapeutic effects.
And here's a fascinating twist – Melittin plays two completely different roles depending on the cell. In normal cells, it protects mitochondria by keeping the membrane intact and lowering ROS. But in cancer cells? It flips the switch. It promotes mitochondrial depolarization, triggers cytochrome C release, activates caspases, and finally kicks off the intrinsic apoptotic pathway. Same molecule, totally different behavior. Pretty wild, right?