Ecgonine

Ecgonine at a Glance

Ecgonine is the tropane amino-alcohol at the centre of the coca alkaloids — a hydroxy-tropane carboxylic acid that serves as the structural nucleus from which cocaine and its relatives are built. Add a methyl ester to its carboxyl group and a benzoyl ester to its hydroxyl, and ecgonine becomes cocaine; remove those two esters again, and cocaine collapses back down to ecgonine ^{1,3Reference 1Roque Bravo R et al. · 2022Cocaine: An updated overview on chemistry, detection, biokinetics, and pharmacotoxicological aspects including abuse patternView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}.

It occurs as a minor native alkaloid in the leaves and seeds of the coca plant (Erythroxylum coca and E. novogranatense) ^{7,8Reference 7Jenkins AJ et al. · 1996Identification and quantitation of alkaloids in coca teaView study →Reference 8Casale JF et al. · 2005Alkaloid content of the seeds from Erythroxylum coca var. cocaView study →}, but most people who carry ecgonine are carrying it as the terminal metabolite of cocaine — the last, pharmacologically spent form after the body has hydrolysed both of cocaine’s ester groups ^{2,3Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}.

The honest headline is that ecgonine itself does very little. The very ester groups it lacks — the C2 methyl ester and the C3 benzoyl ester — are exactly what give cocaine its monoamine-transporter blockade and sodium-channel activity. Structure–activity work shows that stripping those esters, as ecgonine is stripped, removes the binding that a stimulant or local anaesthetic depends on ^{4,10,11Reference 4Gatley SJ · 1991Activities of the enantiomers of cocaine and some related compounds as substrates and inhibitors of plasma butyrylcholinesteraseView study →Reference 10Kline RH Jr et al. · 1994Synthesis of substituted 3-carbamoylecgonine methyl ester analogues: irreversible and photoaffinity ligands for the cocaine receptor/dopamine transporterView study →Reference 11El-Moselhy TF et al. · 2002Synthesis and dopamine transporter binding of 2beta-isopropyl ester analogs of cocaineView study →}. Its practical value is therefore as a biosynthetic and metabolic hub, and a forensic marker of cocaine exposure, not as an active substance in its own right.

The Tropane Nucleus of the Coca Alkaloids

Ecgonine is the shared scaffold of the coca tropanes — the piece every one of them is a decorated version of. Structurally it is an N-methylated bicyclic tropane bearing a carboxylic acid at C2 and a hydroxyl at C3; the two functional groups are the handles onto which the rest of the family is hung.

Cocaine is ecgonine wearing two esters. Cocaine is benzoylecgonine methyl ester: the C2 carboxyl is capped as a methyl ester and the C3 hydroxyl is capped as a benzoyl ester ^{1,3Reference 1Roque Bravo R et al. · 2022Cocaine: An updated overview on chemistry, detection, biokinetics, and pharmacotoxicological aspects including abuse patternView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}. That single sentence organises the whole family:

Ecgonine methyl ester — the methyl ester only (C3 hydroxyl free).
Benzoylecgonine — the benzoyl ester only (C2 carboxyl free).
Cocaine — both esters present.
Ecgonine — neither ester; the bare core.

In the plant, this scaffold is where biosynthesis converges before cocaine is finished. Tropane-alkaloid biosynthesis evolved independently in the Erythroxylaceae (coca) and the Solanaceae (nightshades), and in coca the pathway builds methylecgonone and then reduces it — via methylecgonone reductase — to methylecgonine (ecgonine methyl ester), which is finally benzoylated to cocaine ^{9Reference 9Jirschitzka J et al. · 2012Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and ErythroxylaceaeView study →}. The ecgonine skeleton is thus the biosynthetic branch point, related to but distinct from the tropine core that leads to the nightshade tropanes such as atropine.

In the body, the same scaffold is where metabolism ends. Cocaine’s two esters are hydrolysed off — enzymatically and spontaneously — to give ecgonine methyl ester and benzoylecgonine, each of which loses its remaining ester to yield ecgonine as the terminal product ^{2,3Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}. Biosynthesis assembles the esters up to cocaine; metabolism takes them back off down to ecgonine. That round trip is the reason this otherwise obscure molecule matters.

What It's Used For

Ecgonine is unusual for a monograph molecule in that its most robust finding is a negative one: it is the coca tropane that does not do what cocaine does. Its genuine research relevance is as a metabolite and marker, and as a chemical starting point — not as an agent with activity to catalogue.

A metabolic and forensic marker, not a drug:ecgonine and its mono-esters are the standard analytes that confirm cocaine exposure in blood and urine; ecgonine itself is the inert terminal product ^{1,2,3Reference 1Roque Bravo R et al. · 2022Cocaine: An updated overview on chemistry, detection, biokinetics, and pharmacotoxicological aspects including abuse patternView study →Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}.

Minimal intrinsic activity — and the reason is structural:cocaine’s monoamine-transporter blockade and local-anaesthetic action depend on the C2 and C3 esters that ecgonine lacks, so the bare core shows negligible transporter affinity and is not a reinforcing stimulant ^{4,10,11Reference 4Gatley SJ · 1991Activities of the enantiomers of cocaine and some related compounds as substrates and inhibitors of plasma butyrylcholinesteraseView study →Reference 10Kline RH Jr et al. · 1994Synthesis of substituted 3-carbamoylecgonine methyl ester analogues: irreversible and photoaffinity ligands for the cocaine receptor/dopamine transporterView study →Reference 11El-Moselhy TF et al. · 2002Synthesis and dopamine transporter binding of 2beta-isopropyl ester analogs of cocaineView study →}.

A useful chemical scaffold:the ecgonine skeleton is the backbone of the medicinal-chemistry probes built to map cocaine’s binding site at the dopamine transporter ^{10,11Reference 10Kline RH Jr et al. · 1994Synthesis of substituted 3-carbamoylecgonine methyl ester analogues: irreversible and photoaffinity ligands for the cocaine receptor/dopamine transporterView study →Reference 11El-Moselhy TF et al. · 2002Synthesis and dopamine transporter binding of 2beta-isopropyl ester analogs of cocaineView study →}.

The honest headline:essentially all data are on the isolated molecule as an analyte or a synthetic intermediate; there is no whole-plant efficacy story and no human therapeutic use ^{7,8Reference 7Jenkins AJ et al. · 1996Identification and quantitation of alkaloids in coca teaView study →Reference 8Casale JF et al. · 2005Alkaloid content of the seeds from Erythroxylum coca var. cocaView study →}.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. For ecgonine the highest-scoring “application” is analytical, and the low pharmacology score is itself the finding: little support because there is little activity.

Mechanisms

Target / pathway	Effect	Relevant to
Dopamine / norepinephrine transporters (DAT/NET)	negligible affinity — lacks the C2 ester + C3 benzoyl ester that confer cocaine’s reuptake blockade	why ecgonine is not a stimulant
Voltage-gated Na⁺ channels	no meaningful conduction block — the local-anaesthetic action needs the aromatic ester ecgonine lacks	why ecgonine is not an anaesthetic
Plasma butyrylcholinesterase / hepatic carboxylesterases	ecgonine is the product, not the substrate — these enzymes strip cocaine’s esters down to it	metabolic hub
Methylecgonone reductase (plant enzyme)	reduces methylecgonone to methylecgonine en route to cocaine — the biosynthetic step that builds the ecgonine scaffold	biosynthesis in coca

The load-bearing point is the top row: ecgonine’s inactivity is not incidental but structural — it is what cocaine looks like once the pharmacophore esters are gone.

Pharmacokinetics

Ecgonine’s pharmacokinetics are best understood as the downstream end of cocaine’s metabolism. After cocaine enters the body its two esters are removed by parallel routes: spontaneous (non-enzymatic) hydrolysis and hepatic carboxylesterase cleave the benzoyl ester to give benzoylecgonine, while plasma butyrylcholinesterase and carboxylesterases cleave the methyl-linked side to give ecgonine methyl ester ^{3,4,5Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →Reference 4Gatley SJ · 1991Activities of the enantiomers of cocaine and some related compounds as substrates and inhibitors of plasma butyrylcholinesteraseView study →Reference 5Carmona GN et al. · 2005AnimalIntravenous butyrylcholinesterase administration and plasma and brain levels of cocaine and metabolites in ratsView study →}. Together these account for the large majority of a cocaine dose, with only a small fraction going to the oxidative (norcocaine) pathway ^{2,3Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}. Both major metabolites then lose their remaining ester to converge on ecgonine, a polar, water-soluble amino-acid-like molecule that is renally excreted and pharmacologically inert ^{2,3Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}. Bacterial and human esterase studies confirm that ecgonine sits at the bottom of this cascade — the point past which no further ester remains to remove ^{6Reference 6Brim RL et al. · 2011The ability of bacterial cocaine esterase to hydrolyze cocaine metabolites and their simultaneous quantification using high-performance liquid chromatography-tandem mass spectrometryView study →}. A distinct pyrolysis product, anhydroecgonine methyl ester (methylecgonidine), is formed when cocaine is smoked rather than metabolised; it is a separate, reactive and neurotoxic entity — not ecgonine — and is used specifically as a marker of the smoked route ^{13,14Reference 13Garcia RC et al. · 2012Neurotoxicity of anhydroecgonine methyl ester, a crack cocaine pyrolysis productView study →Reference 14Fandiño AS et al. · 2002AnimalStudies on hydrolytic and oxidative metabolic pathways of anhydroecgonine methyl ester (methylecgonidine) using microsomal preparations from rat organsView study →}.

Clinical Trials

There are no clinical trials of ecgonine as a therapeutic — it has no medicinal use and is studied only as a metabolite, an analyte, and a synthetic intermediate.

Completed	Planned	Terminated	Preclinical
—(analytical/forensic characterisation only)	—	—	Metabolism + structure–activity (as cocaine’s inert core)

Last checked: July 2026.

Isolate vs. Plant Studies

For ecgonine the usual isolate-vs-plant tension barely applies, because there is no efficacy claim to attribute to either. Every meaningful dataset is on the isolated molecule or its mono-esters — as forensic analytes quantified in body fluids ^{1,3Reference 1Roque Bravo R et al. · 2022Cocaine: An updated overview on chemistry, detection, biokinetics, and pharmacotoxicological aspects including abuse patternView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}, as native alkaloids identified in coca leaf and seed by chromatographic profiling ^{7,8Reference 7Jenkins AJ et al. · 1996Identification and quantitation of alkaloids in coca teaView study →Reference 8Casale JF et al. · 2005Alkaloid content of the seeds from Erythroxylum coca var. cocaView study →}, and as synthetic scaffolds in transporter-ligand chemistry ^{10,11Reference 10Kline RH Jr et al. · 1994Synthesis of substituted 3-carbamoylecgonine methyl ester analogues: irreversible and photoaffinity ligands for the cocaine receptor/dopamine transporterView study →Reference 11El-Moselhy TF et al. · 2002Synthesis and dopamine transporter binding of 2beta-isopropyl ester analogs of cocaineView study →}. The plant (coca) contributes ecgonine only as a minor alkaloid dwarfed by cocaine, and coca’s own effects are cocaine’s, not ecgonine’s ^{7Reference 7Jenkins AJ et al. · 1996Identification and quantitation of alkaloids in coca teaView study →}. So the honest framing is: isolate data throughout, no plant-versus-isolate efficacy comparison to make, and no human outcome that rests on ecgonine specifically.

Prevalence in Nature

Ecgonine is confined, as a native alkaloid, to the genus Erythroxylum — chiefly the cultivated coca species E. coca and E. novogranatense, where it is present in leaf and seed as a minor tropane alongside the dominant cocaine and a suite of related esters (cinnamoylcocaine, benzoylecgonine, ecgonine methyl ester, tropacocaine and others) catalogued across the roughly 18 alkaloids identified in the genus ^{7,8,12Reference 7Jenkins AJ et al. · 1996Identification and quantitation of alkaloids in coca teaView study →Reference 8Casale JF et al. · 2005Alkaloid content of the seeds from Erythroxylum coca var. cocaView study →Reference 12Novák M et al. · 1984Biological activity of the alkaloids of Erythroxylum coca and Erythroxylum novogranatenseView study →}. In the leaf it is very much a background constituent — cocaine runs at roughly 0.5–1% of leaf dry weight and is the through-line alkaloid, while ecgonine and the other minor tropanes sit well below it ^{7,8,15Reference 7Jenkins AJ et al. · 1996Identification and quantitation of alkaloids in coca teaView study →Reference 8Casale JF et al. · 2005Alkaloid content of the seeds from Erythroxylum coca var. cocaView study →Reference 15Penny ME et al. · 2009Can coca leaves contribute to improving the nutritional status of the Andean population? Food and Nutrition Bulletin. https://pubmed.ncbi.nlm.nih.gov/19927600/View study →}. Its native abundance has not been characterised as a headline figure, and it is far more commonly encountered outside the plant altogether — as the terminal metabolite of cocaine in human and animal tissue ^{2,3Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}. Because the family’s tropane biosynthesis is independent of the nightshades’, ecgonine is not a constituent of the Solanaceae tropane plants, which build their alkaloids on the related tropine core instead ^{9Reference 9Jirschitzka J et al. · 2012Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and ErythroxylaceaeView study →}.

Discovery & Synthesis

Ecgonine entered chemistry as a hydrolysis product of cocaine. Once cocaine was isolated from coca leaf around 1860, chemists treating it with acid or base found that it broke down into benzoic acid, methanol and a new nitrogenous base — ecgonine — which was recognised as the molecule’s core. The full tropane structure shared by ecgonine, tropine and their relatives was established by Richard Willstätter’s landmark syntheses around the turn of the twentieth century, which connected ecgonine to tropinone and thereby to atropine’s skeleton — work that underpinned the eventual total synthesis of cocaine itself.

Ecgonine is not manufactured as a product. In practice it is obtained, if needed, by hydrolysing cocaine or its esters, and it is handled almost entirely as a reference standard and synthetic intermediate in forensic and medicinal chemistry rather than produced for use. Its modern relevance is analytical and biosynthetic, not commercial.

Patents: not yet researched.

Toxicity & Safety

Ecgonine’s intrinsic toxicity is low — stripped of cocaine’s esters, it lacks the transporter and sodium-channel activity that make cocaine cardio- and neurotoxic, and as an inert, renally-cleared terminal metabolite it is not the dangerous member of its family ^{2,3,4Reference 2Inaba T · 1989Cocaine: pharmacokinetics and biotransformation in manView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →Reference 4Gatley SJ · 1991Activities of the enantiomers of cocaine and some related compounds as substrates and inhibitors of plasma butyrylcholinesteraseView study →}. The moderate flag here is regulatory and contextual, not pharmacological: ecgonine is a controlled (Schedule II) cocaine-related substance in the United States, it is a chemical relative and precursor within the coca-tropane family, and its detection in a person always signals cocaine (or coca) exposure — which is where the real risk sits. It should be read as a scheduled tropane, not a benign phytochemical.

Safety at a Glance

Moderate toxicity

Low intrinsic activity. Ecgonine lacks the C2/C3 esters behind cocaine’s stimulant and local-anaesthetic effects, and is the inert terminal metabolite of cocaine.
Controlled substance. A Schedule II cocaine-related tropane in the US — a regulated molecule, not a free phytochemical, despite its low intrinsic toxicity.
A marker of exposure. Its presence reflects cocaine or coca-leaf intake; the associated hazard is the parent compound, not ecgonine itself.
No isolate safety dataset. There is no dedicated human repeat-dose, reproductive or genotoxicity package for isolated ecgonine — absence of harm is not the same as demonstrated safety.

No dedicated reproductive-toxicity dataset exists for isolated ecgonine; the relevant reproductive risk in this family belongs to cocaine and to coca-leaf intake, which deliver absorbable active alkaloid. Pregnancy and lactation decisions are made at the herb/product level (see the coca monograph), not on this molecule page.

Dosage

There is no therapeutic dose of ecgonine — it is not a medicine, a supplement, or an intended intake. It reaches people almost entirely as an inert breakdown product of cocaine, and as a native alkaloid it is only a trace leaf constituent. The only meaningful “quantities” are the analytical concentrations measured in blood and urine during cocaine toxicology, where ecgonine and its mono-esters are quantified to establish exposure ^{1,3Reference 1Roque Bravo R et al. · 2022Cocaine: An updated overview on chemistry, detection, biokinetics, and pharmacotoxicological aspects including abuse patternView study →Reference 3Matsubara K et al. · 1984In vitroIn vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaineView study →}. These are forensic measurements, not doses, and nothing here is a personal recommendation.

References

Roque Bravo R, et al. (2022). Cocaine: An updated overview on chemistry, detection, biokinetics, and pharmacotoxicological aspects including abuse pattern. Toxins. https://pubmed.ncbi.nlm.nih.gov/35448887/
Inaba T (1989). Cocaine: pharmacokinetics and biotransformation in man. Canadian Journal of Physiology and Pharmacology. https://pubmed.ncbi.nlm.nih.gov/2688863/
Matsubara K, et al. (1984). In vivo and in vitro studies on cocaine metabolism: ecgonine methyl ester as a major metabolite of cocaine. Forensic Science International. https://pubmed.ncbi.nlm.nih.gov/6510853/
Gatley SJ (1991). Activities of the enantiomers of cocaine and some related compounds as substrates and inhibitors of plasma butyrylcholinesterase. Biochemical Pharmacology. https://pubmed.ncbi.nlm.nih.gov/2009099/
Carmona GN, et al. (2005). Intravenous butyrylcholinesterase administration and plasma and brain levels of cocaine and metabolites in rats. European Journal of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/15967428/
Brim RL, et al. (2011). The ability of bacterial cocaine esterase to hydrolyze cocaine metabolites and their simultaneous quantification using high-performance liquid chromatography-tandem mass spectrometry. Molecular Pharmacology. https://pubmed.ncbi.nlm.nih.gov/21885621/
Jenkins AJ, et al. (1996). Identification and quantitation of alkaloids in coca tea. Forensic Science International. https://pubmed.ncbi.nlm.nih.gov/8819993/
Casale JF, Toske SG, et al. (2005). Alkaloid content of the seeds from Erythroxylum coca var. coca. Journal of Forensic Sciences. https://pubmed.ncbi.nlm.nih.gov/16382835/
Jirschitzka J, et al. (2012). Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and Erythroxylaceae. Proceedings of the National Academy of Sciences USA. https://pubmed.ncbi.nlm.nih.gov/22665766/
Kline RH Jr, et al. (1994). Synthesis of substituted 3-carbamoylecgonine methyl ester analogues: irreversible and photoaffinity ligands for the cocaine receptor/dopamine transporter. Journal of Medicinal Chemistry. https://pubmed.ncbi.nlm.nih.gov/8035432/
El-Moselhy TF, et al. (2002). Synthesis and dopamine transporter binding of 2beta-isopropyl ester analogs of cocaine. European Journal of Medicinal Chemistry. https://pubmed.ncbi.nlm.nih.gov/11858849/
Novák M, et al. (1984). Biological activity of the alkaloids of Erythroxylum coca and Erythroxylum novogranatense. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/6379304/
Garcia RC, et al. (2012). Neurotoxicity of anhydroecgonine methyl ester, a crack cocaine pyrolysis product. Toxicological Sciences. https://pubmed.ncbi.nlm.nih.gov/22523227/
Fandiño AS, et al. (2002). Studies on hydrolytic and oxidative metabolic pathways of anhydroecgonine methyl ester (methylecgonidine) using microsomal preparations from rat organs. Chemical Research in Toxicology. https://pubmed.ncbi.nlm.nih.gov/12482236/
Penny ME, et al. (2009). Can coca leaves contribute to improving the nutritional status of the Andean population? Food and Nutrition Bulletin. https://pubmed.ncbi.nlm.nih.gov/19927600/