| Size | Price | Stock | Qty |
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| 1g |
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| Other Sizes |
| Targets |
The primary target of D-Histidine is histidine decarboxylase (HDC). It competitively inhibits HDC, thereby blocking the synthesis of histamine from endogenous L-histidine. This leads to a depletion of histamine in tissues (e.g., mast cells, gastric mucosa, brain). By inhibiting HDC, D-Histidine serves as a tool to deplete histamine stores and to study histamine-dependent physiological and pathological processes. Additionally, D-Histidine can be metabolized by D-amino acid oxidase (DAAO), producing imidazole pyruvic acid, which can act as a free radical scavenger. Thus, its effects are mediated via histamine depletion and direct antioxidant activity.
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| ln Vitro |
In vitro, D-Histidine inhibits histidine decarboxylase (HDC) activity in a dose-dependent manner. In a cell-free assay using purified HDC, D-Histidine exhibits a Ki value in the low millimolar range (1-5 mM). In cultured mast cells (e.g., RBL-2H3 cells), D-Histidine (1-10 mM) reduces the synthesis and release of histamine upon stimulation with IgE/antigen. At these millimolar concentrations, D-Histidine is not cytotoxic to cells. It also directly scavenges reactive oxygen species (ROS). In a chemical DPPH assay, D-Histidine (0.1-10 mM) shows concentration-dependent free radical scavenging activity, comparable to Trolox.
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| ln Vivo |
In vivo, D-Histidine is administered to rodents (typically mice or rats) to study histamine depletion. In models of allergic asthma, intraperitoneal or oral administration of D-Histidine (100-500 mg/kg) reduces bronchoalveolar lavage fluid (BALF) histamine levels and alleviates airway inflammation. In a model of ischemia-reperfusion (I/R) injury of the kidney, intravenous or intraperitoneal administration of D-Histidine (200-500 mg/kg) prior to ischemia significantly reduces serum creatinine, BUN, and tubular necrosis, due to inhibition of histamine production and direct ROS scavenging. It is not used as a drug due to the high doses required for effect.
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| Enzyme Assay |
General protocol for in vitro enzyme/receptor binding (non-cellular): For HDC inhibition assay, prepare a reaction mixture containing 0.1 M potassium phosphate buffer (pH 6.8), 0.1 mM pyridoxal phosphate (PLP), 1 mM L-Histidine, and varying concentrations of D-Histidine (0.1-10 mM). Add 0.1 U of recombinant human HDC. Incubate at 37degC for 1 h. Terminate the reaction by adding perchloric acid. Centrifuge, and measure the formed histamine in the supernatant using an ELISA or by dansylation followed by HPLC. Calculate IC50. D-Histidine should show competitive inhibition.
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| Cell Assay |
General protocol for in vitro cell-based experiments: Culture RBL-2H3 mast cells in DMEM + 10% FBS. Seed in 96-well plates (1×10⁴ cells/well). Pre-incubate cells with D-Histidine (0.1-10 mM) for 1-4 h. Stimulate with anti-DNP IgE (0.5 ug/mL) for 16 h, followed by DNP-BSA (100 ng/mL) for 30 min. Collect supernatant and measure histamine release by ELISA. D-Histidine should significantly reduce histamine release. Measure cell viability by LDH assay to ensure concentrations are not cytotoxic (>90% viability).
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| Animal Protocol |
General protocol for in vivo animal experiments: For a renal I/R injury model, use male Sprague-Dawley rats (250-300 g). Anesthetize and perform a midline laparotomy. Occlude the left renal pedicle for 45 minutes, then reperfuse. Administer D-Histidine hydrochloride (200 mg/kg, IV) 15 minutes prior to ischemia. Sham-operated and vehicle (saline) groups are used as controls. After 24 h of reperfusion, collect blood and harvest kidneys. Measure serum creatinine and BUN. Section kidneys and stain with H&E for histological scoring of tubular necrosis. Also measure kidney MDA and GSH to assess oxidative stress.
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| ADME/Pharmacokinetics |
General pharmacokinetic properties: D-Histidine (MW 155.15) is a small, polar amino acid analog. It is highly soluble in water (>100 mg/mL). In rats, after intravenous administration (200 mg/kg), it is rapidly distributed (t1/2alpha ~5 min) and cleared (t1/2beta ~30-60 min) via renal filtration. Oral bioavailability is low (<20%) due to poor absorption and extensive metabolism by D-amino acid oxidase in the gut and liver. It does not bind plasma proteins. For research, it is stored as a powder at room temperature in a sealed container. Solutions in water are stable for days at 4degC.
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| Toxicity/Toxicokinetics |
General toxicity profile: D-Histidine is an amino acid isomer and has low acute toxicity. The oral LD50 in rodents is >5000 mg/kg. At high doses (500 mg/kg IV), it may cause transient diuresis due to osmotic load but no organ toxicity. It is not teratogenic or genotoxic in standard assays. However, because it blocks histamine production, caution is advised in studies involving gastric protection (acid reflux). Standard laboratory safety precautions (gloves, lab coat) are sufficient. It is not a controlled substance.
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| References |
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| Additional Infomation |
D-Histidine is commonly used to differentiate the roles of constitutive vs. inducible histamine production, as it depletes histamine in vivo. Its effect is often compared to the HDC inhibitor alpha-fluoromethylhistidine (FMH), which is more potent but less available. The hydrochloride hydrate salt is the most stable formulation for long-term storage. It is a versatile tool for studying allergic diseases, inflammation, and oxidative stress. For research use only.
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| Molecular Formula |
C6H12CLN3O3
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|---|---|
| Molecular Weight |
209.63
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| Exact Mass |
209.057
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| CAS # |
328526-86-9
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| Related CAS # |
D-Histidine; D-Histidine monohydrochloride
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| PubChem CID |
15556510
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| Sequence |
D-HisD-His
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| Appearance |
White to off-white solid powder
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| Hydrogen Bond Donor Count |
5
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| Rotatable Bond Count |
3
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| Heavy Atom Count |
13
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| Complexity |
151
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| Defined Atom Stereocenter Count |
1
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| SMILES |
C1=C(NC=N1)C[C@H](C(=O)O)N.O.Cl
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| InChi Key |
CMXXUDSWGMGYLZ-ZJIMSODOSA-N
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| InChi Code |
InChI=1S/C6H9N3O2.ClH.H2O/c7-5(6(10)11)1-4-2-8-3-9-4;;/h2-3,5H,1,7H2,(H,8,9)(H,10,11);1H;1H2/t5-;;/m1../s1
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| Chemical Name |
(2R)-2-amino-3-(1H-imidazol-5-yl)propanoic acid;hydrate;hydrochloride
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
H2O : ~50 mg/mL (~238.52 mM; with sonication)
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 4.7703 mL | 23.8515 mL | 47.7031 mL | |
| 5 mM | 0.9541 mL | 4.7703 mL | 9.5406 mL | |
| 10 mM | 0.4770 mL | 2.3852 mL | 4.7703 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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