-Huperzine A (HupA) Chemical Structure.png)
(-)-Huperzine A (Hup A; Selagine; (-)-Selagine) is a naturally occurring, highly specific and reversible inhibitor of acetylcholinesterase (AChE) with neuroprotective activity. It inhibits AChE with Ki of 7 nM, and exhibits 200-fold more selectivity for G4 AChE over G1 AChE. Chemically, (-)-Huperzine A is an active Lycopodium alkaloid isolated from traditional Chinese herb. It also acts as an NMDA receptor antagonist. (-)-Huperzine A has been investigated as a possible treatment for diseases characterized by neurodegeneration-particularly Alzheimer's disease. Huperzine A is also marketed as a dietary supplement with claims made for its ability to improve memory and mental function.
Physicochemical Properties
| Molecular Formula | C15H18N2O | |
| Molecular Weight | 242.32 | |
| Exact Mass | 242.141 | |
| CAS # | 102518-79-6 | |
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| PubChem CID | 854026 | |
| Appearance | White to off-white solid powder | |
| Density | 1.6±0.1 g/cm3 | |
| Boiling Point | 479.5±25.0 °C at 760 mmHg | |
| Melting Point | 211-216oC | |
| Flash Point | 243.8±23.2 °C | |
| Vapour Pressure | 0.0±1.2 mmHg at 25°C | |
| Index of Refraction | 1.741 | |
| LogP | -0.22 | |
| Hydrogen Bond Donor Count | 2 | |
| Hydrogen Bond Acceptor Count | 2 | |
| Rotatable Bond Count | 0 | |
| Heavy Atom Count | 18 | |
| Complexity | 551 | |
| Defined Atom Stereocenter Count | 2 | |
| SMILES | C/C=C/1\[C@@H]2CC3=C([C@]1(CC(=C2)C)N)C=CC(=O)N3 |
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| InChi Key | ZRJBHWIHUMBLCN-YQEJDHNASA-N | |
| InChi Code | InChI=1S/C15H18N2O/c1-3-11-10-6-9(2)8-15(11,16)12-4-5-14(18)17-13(12)7-10/h3-6,10H,7-8,16H2,1-2H3,(H,17,18)/b11-3+/t10-,15+/m0/s1 | |
| Chemical Name | (1R,9R,13E)-1-amino-13-ethylidene-11-methyl-6-azatricyclo[7.3.1.02,7]trideca-2(7),3,10-trien-5-one | |
| Synonyms |
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| HS Tariff Code | 2934.99.9001 | |
| Storage |
Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
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| Shipping Condition | Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs) |
Biological Activity
| Targets |
Acetylcholinesterase (AChE) (Ki = 0.025 μM; IC50 = 0.086 μM) [2] Butyrylcholinesterase (BuChE) (weaker affinity compared to AChE) [2] N-methyl-D-aspartate (NMDA) receptor [3] |
| ln Vitro |
(-)-Huperzine A (1 μM; 2 hours) attenuates neuronal damage caused by Aβ23-35 (20 μM) [2]. (-)-Huperzine A (100 μM) reversibly suppresses NMDA-induced currents (IC50=126 μM) in whole-cell voltage-clamp recordings in CA1 pyramidal neurons that had been acutely separated from the rat hippocampal [3]. In rat dissociated hippocampal neurons, (−)-Huperzine A (HupA) inhibited NMDA-induced current in a concentration-dependent manner. The inhibition was reversible, and the effect was more pronounced at higher NMDA concentrations [3] (−)-Huperzine A (HupA) showed potent and selective inhibition of AChE, with a much lower inhibitory effect on BuChE. It bound to the active site of AChE, preventing the hydrolysis of acetylcholine [2] In vitro models relevant to neuronal degeneration, (−)-Huperzine A (HupA) exerted neuroprotective effects by reducing oxidative stress and inhibiting neuronal apoptosis [4] |
| ln Vivo |
In rats with degeneration brought on by icv infusion of beta-amyloid-(1-40), (-)-Huperzine A (0.1-0.2 mg/kg; intraperitoneal injection; daily; for 12 days) lessens neuronal damage and cognitive dysfunction [5]. In rats injected with β-amyloid protein-(1-40) (Aβ1-40), intraperitoneal administration of (−)-Huperzine A (HupA) (0.15 and 0.3 mg/kg) attenuated cognitive dysfunction as evaluated by the Morris water maze test. It also reduced neuronal degeneration in the hippocampus and cerebral cortex, along with decreased oxidative damage markers [5] Acute administration of (−)-Huperzine A (HupA) (5 and 10 mg/kg, ip) to rats did not cause significant changes in liver histology, but slightly increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels at the higher dose; these changes were transient [1] In various animal models of memory impairment (e.g., scopolamine-induced), (−)-Huperzine A (HupA) improved learning and memory functions by increasing acetylcholine levels in the brain [2] |
| Enzyme Assay |
Prepare AChE-containing homogenates from appropriate tissues. Dilute the homogenate to a working concentration and add to reaction tubes with different concentrations of (−)-Huperzine A (HupA), followed by incubation at 37°C for 15 minutes. Add acetylthiocholine iodide as the substrate and continue incubation for 30 minutes. Stop the reaction with a chromogenic reagent, measure the absorbance at a specific wavelength, and calculate the enzyme inhibition rate to determine IC50 or Ki values [2] For BuChE inhibition assay, use butyrylthiocholine iodide as the substrate and follow a similar procedure as the AChE assay. Compare the inhibitory potency of (−)-Huperzine A (HupA) on BuChE with that on AChE [2] |
| Cell Assay |
Isolate hippocampi from neonatal rats, dissociate into single neurons by enzymatic digestion and mechanical trituration, and seed them in culture dishes coated with appropriate substrates. After culturing for 7-14 days to allow neuron maturation, treat the cells with different concentrations of (−)-Huperzine A (HupA) for a specified time. Use patch-clamp technique to record NMDA-induced current changes before and after drug treatment [3] Cultivate neuronal cells relevant to neurodegeneration models, expose them to neurotoxic stimuli (e.g., Aβ1-40), and co-treat with (−)-Huperzine A (HupA) at various concentrations. Detect cell viability using a colorimetric assay, measure apoptotic rates by flow cytometry, and assess oxidative stress markers (e.g., reactive oxygen species, malondialdehyde) through specific detection kits [4] |
| Animal Protocol |
Animal/Disease Models: Male SD (Sprague-Dawley) rats (220-280 g)[5] Doses: 0.1 mg/kg, 0.2 mg/kg Route of Administration: intraperitoneal (ip)injection, daily, for 12 days Experimental Results: Partly reversed the down-regulation of anti-apoptotic Bcl-2 and the up-regulation of pro-apoptotic Bax and P53 proteins and decreased the apoptosis that normally followed b-amyloid injection; alleviated the cognitive dysfunction induced by b-amyloid protein-(1-40). Acute liver effect study: Adult rats are randomly divided into control and treatment groups. (−)-Huperzine A (HupA) is dissolved in normal saline and administered intraperitoneally at doses of 5 and 10 mg/kg. The control group receives an equal volume of normal saline. Rats are sacrificed 24 hours after administration, and serum is collected to measure ALT and AST levels; liver tissues are harvested for histopathological examination [1] Aβ1-40-induced cognitive impairment model: Adult rats are anesthetized and stereotaxically injected with Aβ1-40 into the hippocampus to establish the model. One week after model establishment, (−)-Huperzine A (HupA) is administered intraperitoneally at doses of 0.15 and 0.3 mg/kg once daily for 14 consecutive days. The control group receives the same volume of vehicle. Cognitive function is evaluated using the Morris water maze test before sacrifice; brain tissues are collected for histological and biochemical analyses [5] Scopolamine-induced memory impairment model: Rats are given (−)-Huperzine A (HupA) via oral gavage at doses of 0.1-0.5 mg/kg 30 minutes before scopolamine injection. Scopolamine is administered intraperitoneally to induce memory impairment. Learning and memory functions are assessed using the passive avoidance test or Y-maze test [2] |
| ADME/Pharmacokinetics |
Oral absorption: (−)-Huperzine A (HupA) is well absorbed after oral administration in animals and humans, with an oral bioavailability of approximately 36-40% [2] Distribution: It distributes widely in tissues, with high concentrations in the brain, liver, and kidney. The brain/plasma concentration ratio is about 0.6-0.8 [4] Metabolism: It is mainly metabolized in the liver via cytochrome P450 enzymes, producing several metabolites with reduced activity [2] Excretion: The elimination half-life (t1/2) is approximately 4-6 hours in humans and 2-3 hours in rats. It is excreted primarily via the kidneys, with about 20-30% of the dose excreted unchanged in urine [4] |
| Toxicity/Toxicokinetics |
The acute oral LD50 of (−)-Huperzine A (HupA) is approximately 13.6 mg/kg in mice and 8.5 mg/kg in rats [2] Acute high-dose administration (10 mg/kg, ip) in rats causes mild and transient liver enzyme elevation, but no obvious hepatocellular necrosis or fibrosis [1] Chronic toxicity studies in animals show no significant adverse effects on major organs (liver, kidney, heart) at therapeutic doses. Common mild side effects include nausea, diarrhea, and dizziness, which are dose-related [4] Plasma protein binding rate of (−)-Huperzine A (HupA) is approximately 55-60% [2] |
| References |
[1]. Acute effects of huperzine A and tacrine on rat liver. Acta Pharmacol ogica Sinica, 2003, 24(3):247-250. [2]. Progress in studies of huperzine A, a natural cholinesterase inhibitor from Chinese herbal medicine. Acta Pharmacol Sin. 2006 Jan;27(1):1-26. [3]. Huperzine A, a nootropic alkaloid, inhibits N-methyl-D-aspartate-induced current in rat dissociated hippocampal neurons.Neuroscience. 2001;105(3):663-9. [4]. The pharmacology and therapeutic potential of (−)-huperzine A. J Exp Pharmacol. 2012; 4: 113–123. [5]. Huperzine A attenuates cognitive dysfunction and neuronal degeneration caused by beta-amyloid protein-(1-40) in rat. Eur J Pharmacol. 2001 Jun 15;421(3):149-56. |
| Additional Infomation |
Huperzine A is a sesquiterpene alkaloid isolated from a club moss Huperzia serrata that has been shown to exhibit neuroprotective activity. It is also an effective inhibitor of acetylcholinesterase and has attracted interest as a therapeutic candidate for Alzheimer's disease. It has a role as an EC 3.1.1.7 (acetylcholinesterase) inhibitor, a neuroprotective agent, a plant metabolite and a nootropic agent. It is a sesquiterpene alkaloid, a pyridone, a primary amino compound and an organic heterotricyclic compound. It is a conjugate base of a huperzine A(1+). Huperzine A, is a naturally occurring sesquiterpene alkaloid found in the extracts of the firmoss Huperzia serrata. The botanical has been used in China for centuries for the treatment of swelling, fever and blood disorders. Recently in clinical trials in China, it has demonstrated neuroprotective effects. It is currently being investigated as a possible treatment for diseases characterized by neurodegeneration – particularly Alzheimer’s disease. Huperzine A has been reported in Aspergillus versicolor, Phlegmariurus phlegmaria, and other organisms with data available. Drug Indication Investigated for use/treatment in alzheimer's disease. Mechanism of Action Huperzine A has been found to be an inhibitor of the enzyme acetylcholinesterase. This is the same mechanism of action of pharmaceutical drugs such as [galantamine] and [donepezil] used to treat Alzheimer's disease. Pharmacodynamics Huperzine A is an alkaloid derived from Huperzia serrata (which is available as an herbal product in the US). It is under investigation as an acetylcholinesterase inhibitor. Clinical trials in China have shown that huperzine A is comparably effective to the drugs currently on the market, and may even be somewhat safer in terms of side effects. (−)-Huperzine A (HupA) is a natural alkaloid isolated from Chinese herbal medicines of the Huperzia genus (e.g., Huperzia serrata) [2] Its main mechanism of action involves selective and reversible inhibition of AChE, leading to increased acetylcholine levels in the central nervous system, which improves cholinergic function-related cognitive deficits [4] It also exerts neuroprotective effects by regulating NMDA receptors, reducing oxidative stress, inhibiting neuronal apoptosis, and preventing Aβ aggregation [5] Clinically, it is used for the treatment of mild to moderate Alzheimer's disease and other cognitive impairment disorders [2] It has a better safety profile compared to synthetic AChE inhibitors (e.g., tacrine) with less hepatotoxicity [1] |
Solubility Data
| Solubility (In Vitro) |
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (10.32 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (10.32 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.5 mg/mL (10.32 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: 30% propylene glycol, 5% Tween 80, 65% D5W:30 mg/mL (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 4.1268 mL | 20.6339 mL | 41.2677 mL | |
| 5 mM | 0.8254 mL | 4.1268 mL | 8.2535 mL | |
| 10 mM | 0.4127 mL | 2.0634 mL | 4.1268 mL |