EUK-134 (CAS 81065-76-1) SOD/Catalase Mimetic | Manganese Salen ROS Scavenger & Radioprotectant Powder

EUK-134 CAS 81065-76-1
Synthetic SOD/Catalase Mimetic & Catalytic ROS Scavenger

EUK-134 is a synthetic manganese(III) salen complex engineered to reproduce the activity of two antioxidant enzymes in a single small molecule: it dismutates superoxide like superoxide dismutase (SOD) and decomposes hydrogen peroxide like catalase, while also detoxifying peroxynitrite. Because it works catalytically rather than stoichiometrically, one molecule can neutralise many reactive oxygen species without being consumed - the property that makes EUK-134 a benchmark radioprotectant and oxidative-stress tool compound in neuroprotection, mitochondrial biology, photoprotection and ischemia-reperfusion research.

SOD Mimetic Catalase Mimetic Catalytic Antioxidant ROS Scavenger Radioprotectant Peroxynitrite Scavenger Manganese Salen Neuroprotective

Request a Quote Technical Specs

416.74

MW (C18H18ClMnN2O4)

≥98%

Purity

Dual-enzyme

SOD + Catalase Activity

Molecular Information

Name: EUK-134
CAS: 81065-76-1
Formula: C18H18ClMnN2O4
MW: 416.74 g/mol
Metal Centre: Manganese(III), salen ligand
InChIKey: YUZJJFWCXJDFOQ
-GAMUHHASSA-K
Purity: ≥98%
Appearance: Dark red-brown to brown powder
Solubility: DMSO (~20 mg/mL); ethanol;
water ~2 mg/mL (warmed)
Synonyms: Salen-Mn / Ethylbisiminomethyl-
guaiacol manganese chloride
Storage: -20°C, sealed, dry, protect from light

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CAS Number

81065-76-1

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Molecular Weight

416.74

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Primary Activity

SOD/Catalase Mimetic

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Purity

≥98%

EUK-134 Technical Specifications & Quality Control Parameters

Complete physicochemical properties and QC release data for research-grade EUK-134 manganese salen complex (CAS 81065-76-1)

📋 Physicochemical Properties

Product NameEUK-134
Formal NameChloro[[2,2'-[1,2-ethanediylbis[(nitrilo-kappaN)methylidyne]]bis[6-methoxyphenolato-kappaO]]]-manganese
INCI / Cosmetic NameEthylbisiminomethylguaiacol Manganese Chloride
CAS Number81065-76-1
Molecular FormulaC18H18ClMnN2O4
Molecular Weight416.74 g/mol
Metal ContentManganese(III) centre, ~13.2% Mn (theoretical)
SMILES[Cl-][Mn+3]12([N]3=CC4=CC=CC(OC)=C4[O-]2)N=CC5=CC=CC(OC)=C5[O-]1
InChIKeyYUZJJFWCXJDFOQ-GAMUHHASSA-K
UV lambda-max234 nm, 328 nm
AppearanceDark red-brown to brown (faint to very dark) powder
Chemical ClassSalen-manganese (Schiff base) coordination complex
Related AnaloguesEUK-8 (unsubstituted salen), EUK-189, EUK-207

🔬 Quality Control & Handling

Purity≥98%
FormCrystalline powder
IdentityUV-Vis (234/328 nm), LC-MS, elemental Mn analysis
Catalase-Like ActivityH2O2 consumption, initial rate ~234 µM/min in vitro
SOD-Like ActivityCytochrome c / NBT superoxide dismutation assay
Loss on Drying≤1.0%
Storage Condition-20°C, sealed, dry, protect from light
Solution StoragePrepare fresh; store DMSO stock at -80°C, short term
SolubilityDMSO ~20 mg/mL; ethanol ~1 mg/mL; PBS pH 7.2 ~0.2 mg/mL; water ~2 mg/mL (warmed)
GHS ClassificationGHS07 Warning; H315 skin irritation, H319 eye irritation
QC DocumentationCOA / HPLC / UV-Vis / MS / MSDS
Pack Sizes1g / 5g / 10g / 100g / 1KG
Stock StatusIn Stock
Use StatementResearch use only; not for human or clinical use

Catalytic Targets: The Reactive Oxygen and Nitrogen Species Cascade

EUK-134 does not bind a protein target - it catalytically consumes the reactive species themselves, intercepting the ROS cascade at three sequential points

⚡ Superoxide Anion (O2•-) - SOD-like dismutation 💧 Hydrogen Peroxide (H2O2) - catalase-like decomposition 🔥 Peroxynitrite (ONOO-) - reductive detoxification 🧪 Hydroxyl Radical Formation (Fenton suppression) 🧵 Lipid Peroxidation / Malondialdehyde 🧠 Mitochondrial ROS Burden 🛡️ MAPK / p53 Stress Signalling (indirect) 🧬 Amyloid Fibril Formation (reported inhibition)

How EUK-134 Works: One Molecule, Two Enzyme Activities, Catalytic Turnover

The manganese-salen scaffold cycles through multiple oxidation states, allowing it to perform sequential SOD and catalase chemistry indefinitely rather than being consumed once

1. SOD-Like Dismutation of Superoxide

The Mn(III)/Mn(II) redox couple at the centre of the salen ligand accepts and donates electrons, converting two superoxide anions (O2•-) into molecular oxygen and hydrogen peroxide - exactly the reaction catalysed by native superoxide dismutase. This removes the primary radical generated by mitochondrial respiration, NADPH oxidase and ischemia-reperfusion.

2. Catalase-Like Decomposition of H2O2

Unlike a pure SOD mimetic, EUK-134 does not leave hydrogen peroxide behind. The 3-methoxy (guaiacol) substituents on the salicylaldehyde rings - the structural modification that distinguishes EUK-134 from parent compound EUK-8 - markedly enhance catalase-like activity via a high-valent Mn(V)=oxo intermediate, decomposing H2O2 to water and oxygen at an initial rate of roughly 234 µM/min in vitro.

3. Blocking Hydroxyl Radical Generation

By removing both superoxide and hydrogen peroxide, EUK-134 starves the iron- and copper-catalysed Fenton and Haber-Weiss reactions of substrate, preventing formation of the hydroxyl radical - the most destructive ROS, for which no enzymatic scavenger exists in nature.

4. Peroxynitrite Detoxification

EUK-134 also reduces peroxynitrite (ONOO-), the highly reactive nitrogen species formed when superoxide reacts with nitric oxide. This limits protein tyrosine nitration, DNA strand breaks and PARP overactivation in inflammatory and ischemic tissue.

5. Catalytic, Not Stoichiometric

Conventional antioxidants such as ascorbate, N-acetylcysteine, tocopherol or glutathione are consumed 1:1 with each radical scavenged and can themselves become pro-oxidant radicals. EUK-134 turns over catalytically: a single molecule neutralises many ROS equivalents, which is why low micromolar concentrations produce durable cytoprotection.

6. Downstream Cytoprotection

The net effect is reduced lipid peroxidation, preserved mitochondrial membrane potential, blunted MAPK/p53 stress signalling and reduced apoptosis. In vivo, EUK-134 reduced infarct volume by more than 80% in a rat middle cerebral artery occlusion stroke model at 2.5 mg/kg and attenuated kainate-induced neuropathology at 10 mg/kg.

Research Applications of EUK-134 in Oxidative Stress and Radioprotection

A catalytic antioxidant used wherever superoxide and hydrogen peroxide drive pathology - from radiation biology to neurodegeneration and skin science

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Radioprotection & Radiation Mitigation

Ionizing radiation kills largely through water radiolysis and ROS generation. Synthetic SOD/catalase mimetics of the EUK series mitigate capillary endothelial cell apoptosis after irradiation (Vorotnikova et al., Radiation Research 2010) and are studied as radioprotectants and radiation-mitigators for normal tissue sparing in radiotherapy and nuclear-exposure models.

Radiation Biology

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Neurodegeneration & Neuroprotection

EUK-134 prevents oxidative stress and attenuates kainate-induced excitotoxic neuropathology in vivo (Rong et al., PNAS 1999) and is protective in rat middle cerebral artery occlusion stroke models. It is applied across Alzheimer's, Parkinson's and ALS models where mitochondrial ROS and protein oxidation are central.

Neuroscience

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Ischemia-Reperfusion Injury

The reperfusion burst of superoxide and hydrogen peroxide is the canonical target for a dual SOD/catalase mimetic. EUK-134 is used in cerebral, cardiac, renal and hepatic ischemia-reperfusion models - for example reducing renal dysfunction and injury in rat models of renal I/R.

I/R Injury

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Skin Photoprotection & UVB Damage

In primary human keratinocytes, EUK-134 inhibits membrane-damage-induced MAPK pathway activation and reduces p53 accumulation after UVB exposure (Decraene et al., J Invest Dermatol 2004). Under its INCI name, ethylbisiminomethylguaiacol manganese chloride, it is also used as a topical antioxidant active in cosmetic science research.

Dermatology

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Mitochondrial Protection & Bioenergetics

Because mitochondria are the dominant source of cellular superoxide, EUK-134 is widely used to test whether a given phenotype is ROS-dependent - preserving membrane potential, complex I/IV activity and ATP output in models of mitochondrial dysfunction and oxidative phosphorylation stress.

Mitochondria

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Ageing & Lifespan Research

SOD/catalase mimetics of the EUK family are classic tools in the free-radical theory of ageing, including extension of lifespan in Caenorhabditis elegans and reduction of age-associated oxidative damage markers in mammalian tissue - a core reference point in anti-ageing ROS research.

Ageing / Longevity

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Skeletal Muscle Atrophy & Disuse

EUK-134 improves nNOS-mu translocation and reduces skeletal muscle fibre atrophy during short-term mechanical unloading, linking redox signalling to muscle mass regulation in disuse, immobilisation and microgravity models.

Muscle Biology

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Amyloid Aggregation & Protein Misfolding

EUK-134 has been reported to inhibit amyloid fibril formation - including islet amyloid polypeptide (IAPP), beta-amyloid and lysozyme aggregation - and to disrupt pre-formed fibrils, improving viability of cells exposed to IAPP fibrils.

Protein Misfolding

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Inflammation & Acute Lung Injury

Endothelial-targeted liposomal EUK-134 alleviates acute pulmonary inflammation, and the compound is broadly used to test the ROS-dependence of NF-kappaB-driven cytokine responses, neutrophil recruitment and endothelial barrier dysfunction.

Inflammation

Key Publications on EUK-134 and Synthetic SOD/Catalase Mimetics

Foundational studies establishing the salen-manganese catalytic antioxidant class and its protective activity in vivo

Authors & Title	Journal	Year	DOI / PMID
Baker K, Marcus CB, Huffman K, Kruk H, Malfroy B, Doctrow SR. Synthetic combined superoxide dismutase/catalase mimetics are protective as a delayed treatment in a rat stroke model: a key role for reactive oxygen species in ischemic brain injury.	Journal of Pharmacology and Experimental Therapeutics	1998	PMID: 9435181
Rong Y, Doctrow SR, Tocco G, Baudry M. EUK-134, a synthetic superoxide dismutase and catalase mimetic, prevents oxidative stress and attenuates kainate-induced neuropathology.	Proceedings of the National Academy of Sciences USA	1999	10.1073/pnas.96.17.9897
Doctrow SR, Huffman K, Marcus CB, et al. Salen-manganese complexes as catalytic scavengers of hydrogen peroxide and cytoprotective agents: structure-activity relationship studies.	Journal of Medicinal Chemistry	2002	10.1021/jm020207y
Decraene D, Smaers K, Maes D, Matsui M, Declercq L, Garmyn M. A synthetic superoxide dismutase/catalase mimetic (EUK-134) inhibits membrane-damage-induced activation of MAPK pathways and reduces p53 accumulation in UVB-exposed primary human keratinocytes.	Journal of Investigative Dermatology	2004	10.1046/j.0022-202X.2004.22215.x
Vorotnikova E, Rosenthal RA, Tries M, Doctrow SR, Braunhut SJ. Novel synthetic SOD/catalase mimetics can mitigate capillary endothelial cell apoptosis caused by ionizing radiation.	Radiation Research	2010	10.1667/RR1948.1

Available Pack Sizes & Ordering

Research-grade EUK-134 manganese salen complex (CAS 81065-76-1) with full QC documentation - from 1 g research packs to 1 KG bulk batches

Pack sizes: 1 g / 5 g / 10 g / 100 g / 1 KG

Tier	Pack Size	Stock Status	Suitable For	Shipping & Lead Time
Standard	1 g	In Stock	Cell-based ROS assays, SOD/catalase activity characterisation, in vitro screening	Same/next-day dispatch, ambient with ice pack
Medium	5 g	In Stock	Rodent oxidative stress and neuroprotection studies, repeat dosing	Same/next-day dispatch, ambient with ice pack
Large	10 g	In Stock	Radioprotection cohorts, ischemia-reperfusion and multi-organ studies	Same/next-day dispatch, double-bagged foil pouch
Bulk	100 g	In Stock	Topical antioxidant formulation development, stability programmes	2-5 business days, drum/foil pack, quote to confirm
Industrial	1 KG	Made to order	Production-scale supply for cosmetic-science and CDMO programmes	Batch delivery, quote to confirm lead time

💡 Reference sizes shown above; for exact pricing and availability please contact us for a quote. Bulk orders qualify for tiered discounts.

Frequently Asked Questions (FAQ)

Key questions on EUK-134 catalytic antioxidant chemistry, radioprotection, stability and handling

What is EUK-134 (CAS 81065-76-1)?

EUK-134 is a synthetic manganese(III) salen complex with the molecular formula C18H18ClMnN2O4 and molecular weight 416.74 g/mol. Chemically it is chloro[[2,2'-[1,2-ethanediylbis[(nitrilo)methylidyne]]bis[6-methoxyphenolato]]]-manganese, also known as salen-Mn or, in cosmetic nomenclature, ethylbisiminomethylguaiacol manganese chloride. It is a combined superoxide dismutase (SOD) and catalase mimetic: a single small molecule that reproduces the catalytic activity of two distinct antioxidant enzymes.

How is EUK-134 different from vitamin C, vitamin E or N-acetylcysteine?

The difference is catalytic versus stoichiometric chemistry. Conventional antioxidants are consumed in a roughly 1:1 ratio with each radical they scavenge, and the resulting antioxidant radical can itself become pro-oxidant if not regenerated. EUK-134 cycles through Mn oxidation states and is not consumed, so one molecule neutralises many ROS equivalents over time. It also covers a broader spectrum: superoxide (SOD-like), hydrogen peroxide (catalase-like) and peroxynitrite - whereas most dietary antioxidants handle none of these efficiently at physiological concentrations.

What is the difference between EUK-134, EUK-8 and EUK-189?

All three are salen-manganese complexes from the same medicinal chemistry series. EUK-8 is the parent, unsubstituted salen-Mn with strong SOD-like but modest catalase-like activity. EUK-134 adds 3-methoxy (guaiacol) groups to the salicylaldehyde rings, which substantially increases catalase-like activity while retaining SOD activity - making it the preferred dual-function tool compound. EUK-189 and EUK-207 are later analogues with further modified substituents or a macrocyclic ligand designed for improved stability and pharmacokinetics. Structure-activity relationships across the series are detailed in Doctrow et al., J Med Chem 2002.

Why is EUK-134 studied as a radioprotectant?

Most of the cellular damage from ionizing radiation is indirect, mediated by water radiolysis products - hydroxyl radicals, superoxide and hydrogen peroxide - and by the persistent oxidative stress that follows irradiation. A catalytic scavenger that removes superoxide and H2O2 before they generate hydroxyl radicals is therefore mechanistically well matched to radioprotection. EUK-series mimetics mitigate capillary endothelial cell apoptosis after irradiation (Vorotnikova et al., Radiation Research 2010) and are investigated for normal-tissue sparing during radiotherapy and for radiation-mitigation after exposure.

Does EUK-134 scavenge peroxynitrite as well?

Yes. In addition to its SOD-like and catalase-like activities, EUK-134 reductively detoxifies peroxynitrite (ONOO-), the reactive nitrogen species formed when superoxide combines with nitric oxide. Peroxynitrite drives protein tyrosine nitration, DNA single-strand breaks and PARP overactivation, so removing it is important in inflammatory, septic and ischemic models where iNOS is upregulated.

How should EUK-134 be dissolved for cell and animal studies?

EUK-134 dissolves in DMSO at approximately 20 mg/mL, in ethanol at around 1 mg/mL, in PBS pH 7.2 at roughly 0.2 mg/mL, and in water at about 2 mg/mL with gentle warming. For cell culture, prepare a concentrated DMSO stock and dilute into medium with final DMSO at or below 0.1% v/v; typical working concentrations are in the low micromolar range. Aqueous solutions should be prepared fresh because the complex can slowly hydrolyse or lose activity in dilute aqueous buffer over time.

How stable is EUK-134, and how should it be stored?

Store the powder sealed at -20°C, dry and protected from light; under these conditions it is stable long term. The manganese-salen complex is sensitive to strong reducing agents, chelators (EDTA) and extremes of pH, all of which can strip or reduce the metal centre and abolish catalytic activity. Avoid prolonged storage of dilute aqueous solutions, and verify activity with a catalase (H2O2 consumption) or SOD (cytochrome c/NBT) assay if material has been stored in solution.

What colour should EUK-134 powder be?

Genuine EUK-134 is a dark red-brown to brown powder; suppliers describe the colour range as faint brown to very dark brown depending on particle size and lot. The colour arises from the ligand-to-metal charge-transfer bands of the Mn(III)-salen chromophore, which also give the characteristic UV-Vis absorbances at approximately 234 nm and 328 nm - a convenient identity and concentration check.

Is EUK-134 used in cosmetics as well as research?

Yes. Under the INCI name ethylbisiminomethylguaiacol manganese chloride, EUK-134 appears as an antioxidant active in topical formulations, supported by data showing it inhibits UVB-induced MAPK activation and p53 accumulation in human keratinocytes (Decraene et al., J Invest Dermatol 2004). Note that material supplied by us is research grade for laboratory use only; cosmetic or consumer use requires appropriate regulatory grade, testing and approvals in your jurisdiction.

What purity, documentation and pack sizes do you offer?

EUK-134 is supplied at ≥98% purity with a Certificate of Analysis covering HPLC/UV-Vis identity and assay, mass spectrometry confirmation and manganese content, plus MSDS/SDS and Certificate of Origin on request. Functional SOD-like and catalase-like activity data can be provided for qualified programmes. Pack sizes are 1 g, 5 g, 10 g and 100 g in stock, with 1 KG made to order. Please contact us for pricing, lead times and bulk discounts.

Need EUK-134 SOD/Catalase Mimetic for Your Oxidative Stress Research?

EUK-134 (CAS 81065-76-1) - catalytic ROS scavenger and radioprotectant, C18H18ClMnN2O4, MW 416.74, purity ≥98% with COA
Available in 1g / 5g / 10g / 100g / 1KG - request your quote today

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EUK‑134 CAS 81065‑76‑1 High‑Purity Powder SOD & Catalase Mimetic Antioxidant Raw Material