Quick Summary
9-Methyl-β-carboline (9-Me-BC) is a methylated heterocyclic amine of the β-carboline family. First characterized as a potent stimulator of dopaminergic neuron differentiation, it has since been shown to inhibit both monoamine oxidase A (IC50 = 1 μM) and monoamine oxidase B (IC50 = 15.5 μM), upregulate neurotrophic factors including BDNF and artemin, promote neurite outgrowth, and restore tyrosine hydroxylase expression in Parkinsonian models. These multimodal properties make 9-Me-BC a uniquely versatile tool compound for neuroscience research, particularly in dopaminergic system degeneration, neuroprotection, and cognitive enhancement studies.
1 What Is 9-Methyl-β-carboline?
9-Methyl-β-carboline (abbreviated as 9-Me-BC or 9-MBC) is a synthetic methylated derivative of the endogenous β-carboline alkaloid norharmane (β-carboline). It belongs to the pyrido[3,4-b]indole class of heterocyclic amines — a structural family known for diverse neuropharmacological activities including interactions with monoamine oxidase enzymes, benzodiazepine binding sites, and serotonin and dopamine receptors.
The compound is synthesized via the Eschweiler–Clarke reductive methylation of freebase β-carboline (norharmane), introducing a single methyl group at the N-9 position of the indole ring system. This seemingly small structural modification produces a dramatic shift in biological activity: unlike its parent compound norharmane, 9-Me-BC exhibits pronounced dopaminergic neurotrophic and neuroprotective properties that are independent of dopamine transporter-mediated uptake.
9-Me-BC has attracted sustained research interest since the landmark 2010 publication by Polanski, Enzensperger, Reichmann, and Gille in the Journal of Neurochemistry, which described its "exceptional properties" as a stimulator, protector, and regenerator of dopaminergic neurons. Subsequent work from the same group, including a 2020 study in the Journal of Neural Transmission, elucidated its astrocyte-mediated neurotrophic mechanisms and confirmed its direct MAO inhibitory activity.
Research Status: 9-Me-BC is classified as a research chemical and analytical reference standard. It has not been approved by the FDA, EMA, or any other regulatory body for therapeutic use in humans. All data presented herein pertain to preclinical in vitro and in vivo (rodent) studies.
2 Physicochemical Data & Product Specifications
| Parameter | Value |
|---|---|
| IUPAC Name | 9-Methyl-9H-pyrido[3,4-b]indole (also: 5-Methyl-5H-pyrido[3,4-b]indole) |
| CAS Number | 2521-07-5 |
| Molecular Formula | C12H10N2 |
| Molecular Weight | 182.22 g/mol |
| Chemical Class | β-Carboline; methylated heterocyclic amine; pyridoindole |
| Appearance | White to pale yellow-green crystalline powder |
| Melting Point | 105 – 109 °C |
| Boiling Point | 367.3 °C at 760 mmHg (predicted) |
| Density | 1.17 g/cm3 (predicted) |
| Purity (HPLC) | ≥98% (research grade); ≥99% available on request |
| Water Solubility | ~0.2 g/L at 25 °C (very slightly soluble) |
| DMF Solubility | 20 mg/mL |
| DMSO Solubility | 20 mg/mL |
| DMSO:PBS (pH 7.2, 1:3) Solubility | 0.33 mg/mL |
| pKa | 8.21 ± 0.30 (predicted) |
| LogP | 2.73 |
| λmax | 217, 237, 290 nm (361 nm in cyclohexane) |
| PSA (Polar Surface Area) | 17.82 Å2 |
Purity Note: Our standard supply is ≥98% by HPLC with identity confirmation by 1H-NMR and LC-MS. A full Certificate of Analysis (COA) including chromatogram, residual solvent profile, and heavy metal analysis is provided with each shipment. Custom purity levels (≥99%) and salt forms are available for institutional orders.
3 Mechanism of Action: A Multimodal Dopaminergic Neurotrophic Agent
9-Me-BC is distinguished from single-mechanism research compounds by its three-pronged action on the dopaminergic system: (1) direct MAO enzyme inhibition, (2) PI3K/Akt-mediated neurotrophic factor upregulation in astrocytes, and (3) anti-inflammatory cytokine suppression. These mechanisms act synergistically to stimulate, protect, and regenerate dopaminergic neurons.
3.1 Dual MAO-A / MAO-B Inhibition
9-Me-BC directly inhibits both isoforms of monoamine oxidase with a clear selectivity profile:
- MAO-A: IC50 = 1 μM — Potent inhibition comparable to other β-carboline MAO inhibitors. MAO-A preferentially deaminates serotonin, norepinephrine, and dopamine.
- MAO-B: IC50 = 15.5 μM — Approximately 15-fold selectivity for MAO-A over MAO-B. MAO-B preferentially metabolizes dopamine and phenylethylamine and is the predominant isoform in the human basal ganglia.
This dual inhibition profile contributes to elevated synaptic dopamine levels and reduced oxidative stress from MAO-mediated dopamine catabolism. The MAO-A preference aligns with the broader β-carboline structural family pattern, though 9-Me-BC's MAO-B activity at higher concentrations provides broader catecholamine protection than pure MAO-A inhibitors.
3.2 PI3K/Akt-Dependent Neurotrophic Factor Upregulation
In a key 2020 study by Gille et al., 9-Me-BC was shown to stimulate astrocytes — the supporting glial cells of the central nervous system — to express a cascade of neurotrophic and neuroprotective factors via the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. This was demonstrated by complete blockade of all neurotrophic effects upon co-administration of LY-294002, a selective PI3K inhibitor.
| Neurotrophic Factor | Fold Change (mRNA) | Functional Role |
|---|---|---|
| Artemin (Artn) | 3.2× | GDNF family ligand; promotes dopaminergic neuron survival and neurite outgrowth |
| BDNF | 2.0× | Brain-derived neurotrophic factor; synaptic plasticity, neuronal survival, dendritogenesis |
| Neurotrophin-3 (NT-3) | 1.8× | Supports survival and differentiation of existing neurons |
| Skp1 | 1.5× | S-phase kinase-associated protein 1; may increase α-synuclein turnover rate |
| TGF-β2 | 1.4× | Transforming growth factor beta 2; anti-inflammatory, neuroprotective |
| NCAM1 | 1.4× | Neural cell adhesion molecule; neurite outgrowth, synaptic remodeling |
The 3.2-fold upregulation of artemin is particularly noteworthy, as artemin is a member of the GDNF (glial cell line-derived neurotrophic factor) family — the most potent known survival factors for midbrain dopaminergic neurons, which are the cell population selectively lost in Parkinson's disease.
3.3 Tyrosine Hydroxylase (TH) Stimulation & Dopaminergic Differentiation
In primary mesencephalic cell cultures, 9-Me-BC produced a maximum 33% increase in the number of tyrosine hydroxylase-positive (TH+) dopaminergic neurons at a concentration of 90 μM after 48 hours of treatment. Tyrosine hydroxylase is the rate-limiting enzyme in dopamine biosynthesis, and the TH+ phenotype is the gold-standard marker for mature dopaminergic neurons.
Crucially, the effect followed an inverted U-shaped dose-response curve: concentrations of 125 μM and 150 μM progressively decreased the number of TH+ neurons, emphasizing the importance of precise concentration control in experimental protocols.
3.4 MPTP Protection & In Vivo Neuroregeneration
9-Me-BC inhibits the oxidation of the protoxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) to the active dopaminergic neurotoxin MPP+ in vitro — the same mechanism exploited by MAO-B inhibitors like selegiline and rasagiline. In rodent models, systemic 9-Me-BC administration after unilateral striatal MPP+ lesioning restored the number of TH+ neurons to pre-lesion levels, demonstrating both neuroprotective and neuroregenerative capacity in vivo.
3.5 Mechanism Flow Diagram
4 Core Advantages: Why 9-Me-BC Stands Out
9-Me-BC occupies a unique position in the neuroscience research toolkit. Unlike compounds that target a single node in the dopaminergic system, its multimodal pharmacology addresses three complementary axes simultaneously: neurotransmitter preservation (MAO inhibition), neuronal growth and survival (neurotrophic factor induction), and microenvironment modulation (anti-inflammatory cytokine suppression).
Multimodal Dopaminergic Action
Three synergistic mechanisms in a single molecule: MAO-A/B inhibition, PI3K/Akt-driven neurotrophic factor upregulation, and anti-inflammatory effects — covering neurotransmitter preservation, neuronal growth, and neuroprotection simultaneously.
Quantified TH+ Neuron Stimulation
A reproducible +33% increase in tyrosine hydroxylase-positive dopaminergic neurons at 90 μM in primary mesencephalic cultures — one of the clearest in vitro dopaminergic differentiation signals among research compounds.
Astrocyte-Mediated Mechanism
Unlike direct neuronal stimulants, 9-Me-BC acts partially through astrocyte-mediated paracrine signaling — stimulating glial cells to secrete a physiological cocktail of growth factors rather than administering a single recombinant factor.
Peer-Reviewed Validation
Published in the Journal of Neurochemistry (2010) and Journal of Neural Transmission (2020) with open-access full-text availability. Dose-response parameters, pathway inhibitors, and in vivo behavioral data are fully documented and reproducible.
Well-Defined Solubility Profile
Soluble in DMF (20 mg/mL) and DMSO (20 mg/mL) for in vitro dosing. Aqueous solubility is limited (0.2 g/L), enabling straightforward formulation strategies for both cell culture and in vivo administration.
Non-Controlled Research Chemical
Not scheduled under the UN Convention on Psychotropic Substances, US Controlled Substances Act, or EU narcotics regulations. Ships as a standard research chemical with simplified customs documentation.
4.1 Comparison with Established Dopaminergic Research Compounds
| Attribute | 9-Me-BC | Selegiline | Rasagiline | GDNF (Recombinant) |
|---|---|---|---|---|
| MAO-A Inhibition | IC50 = 1 μM | Weak / negligible | Weak / negligible | None |
| MAO-B Inhibition | IC50 = 15.5 μM | Irreversible (selective) | Irreversible (selective) | None |
| Neurotrophic Factor Induction | ✓ Multi-factor | ✓ Bcl-2 only | Minimal | Single factor (exogenous) |
| TH+ Neuron Stimulation | ✓ +33% (in vitro) | Indirect only | Indirect only | ✓ Strong |
| Anti-Inflammatory Activity | ✓ Cytokine suppression | Minimal | Minimal | None |
| MPTP Protection | ✓ Yes (in vitro) | ✓ Yes | ✓ Yes | None |
| Administration Route | Systemic (in vivo) | Oral | Oral | Intracerebral infusion |
| Regulatory Status | Research chemical | FDA-approved | FDA-approved | Investigational |
5 Research Applications & Experimental Use Cases
9-Me-BC's multimodal pharmacology supports investigation across multiple neuroscience sub-disciplines. The following applications are grounded in peer-reviewed preclinical research.
Dopaminergic Neurodegeneration Models
Studies using MPTP, 6-OHDA, and rotenone lesion models to evaluate neuroprotective and neurorestorative interventions. 9-Me-BC's combined MAO-B inhibition and neurotrophic factor induction makes it particularly suited for dual-mechanism PD research protocols.
Astrocyte–Neuron Crosstalk Studies
Investigating PI3K/Akt-mediated paracrine signaling from astrocytes to dopaminergic neurons. The OCT-mediated uptake and LY-294002-blockable downstream cascade provide a clean experimental system for dissecting glial-neuronal communication.
Spatial Learning & Hippocampal Dopamine
Rodent radial maze studies demonstrated elevated hippocampal dopamine and improved spatial learning performance with 9-Me-BC administration. Increased dendritic outgrowth in the dentate gyrus suggests hippocampal neuroplasticity effects extending beyond the nigrostriatal system.
Competitive Inhibition Kinetics
9-Me-BC serves as a reference compound for β-carboline MAO structure-activity relationship (SAR) studies, given its well-characterized IC50 values for both isoforms and the availability of structural analogs (norharmane, harmane, harmine) for comparative analysis.
Cytokine Modulation in Glial Cultures
9-Me-BC reduces expression of pro-inflammatory cytokines in dopaminergic neuron-glia co-cultures. This anti-inflammatory activity, coupled with its neurotrophic effects, supports investigations into neuroinflammatory components of neurodegenerative disease.
Lead Optimization & Reference Standard
Pharmaceutical research teams use 9-Me-BC as a reference inhibitor in HTS assay validation for novel MAO inhibitors, as a benchmark for dopaminergic neurotrophic compound screening, and as a structural template for β-carboline-based medicinal chemistry programs.
5.1 Recommended Working Concentrations
| Application | Recommended Range | Notes |
|---|---|---|
| In vitro TH+ neuron differentiation | 75 – 90 μM | Peak effect at 90 μM; inverted U-shaped curve; avoid >125 μM |
| MAO-A inhibition assay | 0.1 – 10 μM | IC50 = 1 μM; pre-incubate 30 min with enzyme |
| MAO-B inhibition assay | 1 – 100 μM | IC50 = 15.5 μM; expect 15-fold selectivity window |
| Astrocyte neurotrophic factor induction | 50 – 100 μM | Monitor BDNF, Artn mRNA at 24–48 h post-treatment |
| MPTP protection (in vitro) | 10 – 50 μM | Co-administer with MPTP; measure MPP+ formation by HPLC |
6 Packaging, Storage, Shipping & Regulatory Compliance
6.1 Storage Conditions
| Condition | Recommendation |
|---|---|
| Long-term storage | −20 °C, airtight container, protected from light |
| Short-term storage | 2 – 8 °C, desiccated, protected from light |
| Stability | ≥5 years at −20 °C (lyophilized powder) |
| Solution stability | Prepare fresh solutions in DMF or DMSO immediately before use; avoid prolonged storage of dissolved compound |
| Light sensitivity | Photosensitizing — always store in amber vials or foil-wrapped containers |
| Moisture sensitivity | Hygroscopic — store with desiccant; minimize exposure to ambient humidity |
Photosensitivity Alert: 9-Me-BC exhibits documented photosensitizing effects. All handling and storage must be conducted under low-light or amber-filtered conditions. Prolonged exposure to ambient or UV light will degrade the compound and may generate reactive photoproducts.
6.2 Shipping & Logistics
Ambient Shipping
Lyophilized powder is stable at ambient temperatures during transit. Standard courier (FedEx, DHL, UPS) with temperature data logger available on request.
Cold Chain Option
For pre-dissolved aliquots or large-volume shipments, dry ice or gel-pack cold chain logistics are available at additional cost.
Customs Documentation
Full commercial invoice, packing list, COA, and MSDS provided. HS code: 2933.99.9701 (heterocyclic compounds with nitrogen hetero-atoms only).
6.3 Regulatory Status & Controlled Substance Statement
Non-Controlled Research Chemical. 9-Methyl-β-carboline is not listed on any schedule of the UN Convention on Psychotropic Substances (1971), the US Controlled Substances Act (CSA), the EU Narcotic Drugs and Psychotropic Substances regulations, or the Chinese Catalog of Controlled Chemicals. It is not a precursor to any scheduled substance and does not fall under any export control classification beyond standard HS code requirements.
6.4 Packaging Options
| Package Size | Container Type | Typical Use Case |
|---|---|---|
| 25 mg | Amber glass vial, PTFE-lined cap, argon-backfilled | Evaluation / pilot studies |
| 100 mg | Amber glass vial, PTFE-lined cap, argon-backfilled | Standard in vitro research |
| 500 mg | Amber glass bottle, PTFE-lined cap, vacuum-sealed foil pouch | Extended in vivo studies |
| 1 g & above | Amber glass bottle, vacuum-sealed foil pouch with desiccant | Institutional / screening programs |
6.5 Safety Handling
| Hazard | Classification |
|---|---|
| GHS Signal Word | Warning |
| H315 | Causes skin irritation |
| H319 | Causes serious eye irritation |
| Precautionary Measures | P264 (wash hands thoroughly after handling); P280 (wear protective gloves / eye protection); P302+P352 (IF ON SKIN: wash with plenty of water); P305+P351+P338 (IF IN EYES: rinse cautiously with water for several minutes) |
7 Frequently Asked Questions
Q: What is the exact molecular identity of 9-Me-BC?
9-Methyl-β-carboline (CAS 2521-07-5) is the N-9 methylated derivative of β-carboline (norharmane). Its IUPAC name is 9-methyl-9H-pyrido[3,4-b]indole. Also referred to as 9-Methylnorharman, 9-MBC, and N-methyl-β-carboline. It belongs to the β-carboline alkaloid family — structurally distinct from both the racetam and cholinergic nootropic classes.
Q: How does 9-Me-BC differ from selegiline and rasagiline?
Selegiline and rasagiline are irreversible, selective MAO-B inhibitors (propargylamine class) that primarily reduce dopamine catabolism. 9-Me-BC is a reversible, dual MAO-A/B inhibitor (β-carboline class) that additionally upregulates multiple neurotrophic factors (BDNF, artemin, NT-3, NCAM1, TGF-β2) via the PI3K/Akt pathway and suppresses inflammatory cytokines. It is a fundamentally different pharmacological entity with a broader, multimodal mechanism.
Q: What purity grade do you supply?
Our standard supply is ≥98% by HPLC, with identity confirmed by 1H-NMR and LC-MS. ≥99% purity is available for institutional orders upon request. Each batch includes a full COA with chromatogram, residual solvent analysis, heavy metal testing (≤10 ppm), and endotoxin quantification.
Q: Is 9-Me-BC water-soluble? How should I dissolve it for experiments?
9-Me-BC has very low aqueous solubility (~0.2 g/L at 25 °C). For in vitro studies, dissolve in DMF or DMSO (both at 20 mg/mL) as a stock solution, then dilute into aqueous buffer or culture medium. Note that DMSO:PBS (pH 7.2, 1:3) solubility drops to 0.33 mg/mL, so pre-test your final working solution for precipitation. Sonication and gentle warming (not exceeding 40 °C) may aid dissolution.
Q: Is 9-Me-BC a controlled or scheduled substance?
No. 9-Me-BC is not listed on any international or national controlled substance schedule. It is not regulated under the UN Convention on Psychotropic Substances, the US Controlled Substances Act, or EU narcotics legislation. It ships as a standard research chemical with routine customs documentation (HS code 2933.99.9701).
Q: What is the recommended storage protocol?
Store lyophilized powder at −20 °C in an airtight amber glass container with desiccant. The compound is stable for ≥5 years under these conditions. Critical: protect from light at all times — 9-Me-BC is photosensitizing and will degrade upon exposure to ambient or UV light. For short-term use (1–2 weeks), storage at 2–8 °C in a light-protected container is acceptable.
Q: Has 9-Me-BC been tested in human clinical trials?
No. All published data on 9-Me-BC are from preclinical studies (in vitro cell culture and in vivo rodent models). No human clinical trials have been conducted. The compound is sold strictly as a research chemical and analytical reference standard for laboratory use only. It is not approved for human therapeutic use by any regulatory authority.
Q: What is the significance of the PI3K/Akt pathway in 9-Me-BC's mechanism?
The PI3K/Akt pathway is critical: the neurotrophic and neurostimulative effects of 9-Me-BC are completely blocked by LY-294002, a selective PI3K inhibitor. This establishes PI3K/Akt as the obligate upstream signaling cascade for 9-Me-BC's neurotrophic factor induction. Researchers investigating downstream Akt targets (mTOR, FOXO, GSK-3β) can use 9-Me-BC as a clean tool for pathway activation studies.
Q: What are the key differences between 9-Me-BC and other β-carbolines like harmine or harmane?
While harmine and harmane are primarily studied as MAO inhibitors and benzodiazepine site ligands, 9-Me-BC is distinguished by its dopaminergic neurotrophic activity — specifically, its ability to increase TH+ neuron counts, promote neurite outgrowth, and upregulate neurotrophic factors. The N-9 methyl group is the critical structural determinant: the parent compound norharmane lacks these neurotrophic properties entirely, demonstrating that the methyl substitution is not merely a pharmacokinetic modification but a key pharmacophoric feature.
Q: Do you provide bulk or custom packaging for institutional orders?
Yes. We offer tiered volume pricing from milligram to multi-gram scale. Institutional accounts may request custom aliquoting, dedicated batch reservation, custom salt forms, and net-30 payment terms. Contact our procurement team with your specific requirements for a tailored quotation.
Q: How does 9-Me-BC affect cognition in animal models?
In rodent radial maze tests, 9-Me-BC administration was associated with improved spatial learning performance and elevated hippocampal dopamine levels. Increased dendritic outgrowth was observed in the dentate gyrus. These effects extend beyond the classical nigrostriatal dopaminergic system, suggesting that 9-Me-BC may influence mesolimbic and mesocortical dopamine pathways relevant to learning, memory, and motivated behavior.
Q: What documentation do you provide with each shipment?
Each order includes: (1) Certificate of Analysis (COA) with HPLC chromatogram, (2) Material Safety Data Sheet (MSDS/SDS), (3) 1H-NMR spectrum, (4) LC-MS trace, (5) residual solvent analysis, (6) heavy metal testing report, (7) commercial invoice, and (8) packing list. Additional documentation (stability data, impurity profile, elemental analysis) is available for institutional orders.
Source High-Purity 9-Methyl-β-carboline for Your Research
≥98% HPLC purity • Full COA + NMR + LC-MS documentation • Global ambient or cold-chain shipping • Institutional bulk pricing available
Research Use Only. 9-Methyl-β-carboline is sold as a research chemical and analytical reference standard for in vitro and preclinical laboratory research applications only. It is not a dietary supplement, pharmaceutical ingredient, or finished drug product. It is not intended for human or veterinary therapeutic, diagnostic, or prophylactic use. Purchasers are responsible for compliance with all applicable local, national, and institutional regulations governing the acquisition, handling, storage, and use of research chemicals. This content is for informational and educational purposes only and does not constitute medical or legal advice.