Mitragynine (10 nM-1 μM) decreases KCl-induced Ca2+ influx in neuroblastoma cells [2], and mitragynine (1 μM) blocks T-type and L-type Ca2+ channel currents in N1E-115 neuroblastoma cells [2].

Mitragynine (300 nM-10 μM) reduces the twitching response of the guinea pig vas deferens following electrical stimulation in a concentration-dependent manner [2]. Mitragynine (3-10 μM) reduces nicotine-induced (1 mM) vas deferens contraction in guinea pigs in a concentration-dependent manner [2]. Mitragynine (1.5 mg/kg IV, 50 mg/kg PO, single dosage) is removed biphasically from plasma, and oral absorption is slow, delayed, and partial [3]. Pharmacokinetic characteristics of mitragynine in male Sprague-Dawley rats [3]. IV (1.5 mg/kg) PO (50 mg/kg) Cmax (μg/mL) 2.3±1.2 0.70±0.21 Tmax (hr) 1.2±1.1 4.5±3.6 t1/2 (h) 2.9±2.1 6.6±1.3 Abs t1 /2 (h) 1.72±0.90 AUC0-∞ (μg/mL·h) 9.2±6.5 8.2±3.0 CL (L/h·kg) 0.29±0.27 7.0±3.0 Vd (L/kg) 0.79±0.42 64±23 F (%) 3.03±1.47

Animal/Disease Models: Male SD (SD (Sprague-Dawley)) rat (12-16 weeks old, 280-315 g) [3]
Doses: 1.5 mg/kg intravenously (iv) (iv)(iv), 50 mg/kg orally
Route of Administration: intravenous (iv) (iv)Injection or oral administration, single dose (pharmacokinetic/PK/PK analysis)
Experimental Results: biphasic elimination from plasma, slow, prolonged and incomplete oral absorption, absolute oral bioavailability value calculated to be 3.03%.

Absorption, Distribution and Excretion
... LC-MS/MS analysis... was applied to quantify mitragynine in plasma samples of rats (n=8 per sampling time) treated with a single oral dose of 20 mg/kg. The following pharmacokinetic parameters were obtained (mean): maximum plasma concentration: 424 ng/mL; time to reach maximum plasma concentration: 1.26 hr; elimination half-life: 3.85 hr, apparent total clearance: 6.35 L/hr/kg, and apparent volume of distribution: 37.90 L/kg.

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Metabolism / Metabolites
Mitragyna speciosa (Kratom) is ... a drug of abuse. When monitoring its abuse in urine, several alkaloids and their metabolites must be considered. In former studies, mitragynine (MG), its diastereomer speciogynine (SG), and paynantheine and their metabolites could be identified in rat and human urine using /Liquid Chromatography - Tandem Mass Spectometry/ (LC-MS(n)). In Kratom users' urines, besides MG and SG, further isomeric compounds were detected. To elucidate whether the MG and SG diastereomer speciociliatine (SC) and its metabolites represent further compounds, the phase I and II metabolites of SC were identified first in rat urine after the administration of the pure alkaloid. Then, the identified rat metabolites were screened for in the urine of Kratom users using the above-mentioned LC-MS(n) procedure. Considering the mass spectra and retention times, it could be confirmed that SC and its metabolites are so far the unidentified isomers in human urine. In conclusion, SC and its metabolites can be used as further markers for Kratom use, especially by consumption of raw material or products that contain a high amount of fruits of the Malaysian plant M. speciosa.
... The aim of /this/ study is to identify the phase I and II metabolites of mitragynine (MG) in rat and human urine after solid-phase extraction (SPE) using liquid chromatography-linear ion trap mass spectrometry providing detailed structure information in the MSn mode particularly with high resolution. The seven identified phase I metabolites indicated that MG was metabolized by hydrolysis of the methylester in position 16, O-demethylation of the 9-methoxy group and of the 17-methoxy group, followed, via the intermediate aldehydes, by oxidation to carboxylic acids or reduction to alcohols and combinations of some steps. In rats, four metabolites were additionally conjugated to glucuronides and one to sulfate, but in humans, three metabolites to glucuronides and three to sulfates.
During studies on the main Kratom alkaloid mitragynine (MG) in rats and humans, several dehydro analogs could be detected in urine of Kratom users, which were not found in rat urine after administration of pure MG. Questions arose as to whether these compounds are formed from MG only by humans or whether they are metabolites formed from the second abundant Kratom alkaloid paynantheine (PAY), the dehydro analog of MG. Therefore, the aim of /this/ study was to identify the phase I and II metabolites of PAY in rat urine after administration of the pure alkaloid. This was first isolated from Kratom leaves. Liquid chromatography-linear ion trap mass spectrometry provided detailed structure information of the metabolites in the MS(n) mode particularly with high resolution. Besides PAY, the following phase I metabolites could be identified: 9-O-demethyl PAY, 16-carboxy PAY, 9-O-demethyl-16-carboxy PAY, 17-O-demethyl PAY, 17-O-demethyl-16,17-dihydro PAY, 9,17-O-bisdemethyl PAY, 9,17-O-bisdemethyl-16,17-dihydro PAY, 17-carboxy-16,17-dihydro PAY, and 9-O-demethyl-17-carboxy-16,17-dihydro PAY. These metabolites indicated that PAY was metabolized via the same pathways as MG. Several metabolites were excreted as glucuronides or sulfates. The metabolism studies in rats showed that PAY and its metabolites corresponded to the MG-related dehydro compounds detected in urine of the Kratom users. In conclusion, PAY and its metabolites may be further markers for a Kratom abuse in addition of MG and its metabolites.

Interactions
Mitragynine (MG), a major alkaloidal constituent extracted from the plant Mitragyna speciosa Korth, is known to exert an opioid-like activity. ... Previous study showed the involvement of opioid systems in the antinociceptive activity of MG in the tail-pinch and hot-plate tests in mice. In /this/ study, to clarify the opioid receptor subtypes involved in the antinociceptive action of MG, ... the effects of selective antagonists for mu-, delta- and kappa- opioid receptors on antinociception caused by the intracerebroventricular (i.c.v.) injection of MG in the tail-pinch and hot-plate tests in mice /were investigated/. The coadministration of a selective mu-opioid antagonist, cyprodime (1-10 ug, i.c.v.) and the pretreatment with a selective mu1-opioid antagonist naloxonazine (1-3 ug, i.c.v.) significantly antagonized the antinociceptive activities of MG (10 ug, i.c.v.) and morphine (MOR, 3 ug, i.c.v.) in the tail-pinch and hot-plate tests. Naltrindole (1-5 ng, i.c.v.), a selective delta-opioid antagonist, also blocked the effects of MG (10 ug, i.c.v.) without affecting MOR (3 ug, i.c.v.) antinociception. Nor-binaltorphimine, a selective kappa-opioid antagonist, significantly attenuated MG (10 ug, i.c.v.) antinociception in the tail-pinch test but not in the hot-plate test at the dose (1 ug, i.c.v.) that antagonized the antinociceptive effects of the selective kappa-opioid agonist U50,488H in both tests, while it had no effect on MOR antinociception in either tests. These results suggest that antinociception caused by i.c.v. MG is dominantly mediated by mu- and delta-opioid receptor subtypes, and that the selectivity of MG for the supraspinal opioid receptor subtypes differs from that of MOR in mice.

[1]. Hassan Z, et al. From Kratom to mitragynine and its derivatives: physiological and behavioural effects related to use, abuse, and addiction. Neurosci Biobehav Rev. 2013 Feb;37(2):138-51.
[2]. Parthasarathy S, et al. Determination of mitragynine in plasma with solid-phase extraction and rapid HPLC-UV analysis, and its application to a pharmacokinetic study in rat. Anal Bioanal Chem. 2010 Jul;397(5):2023-30.
[3]. Matsumoto K, et al. Inhibitory effect of mitragynine, an analgesic alkaloid from Thai herbal medicine, on neurogenic contraction of the vas deferens. Life Sci. 2005 Nov 26;78(2):187-94.

Mitragynine is a monoterpenoid indole alkaloid.
Mitragynine has been reported in Mitragyna speciosa with data available.

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Mechanism of Action
... Mitragynine (MIT), a mu-opioid agonist with antinociceptive and antitussive properties...
Mitragynine, the major alkaloid identified from Kratom, has been reported as a partial opioid agonist producing similar effects to morphine. An interesting minor alkaloid of Kratom, 7-hydroxymitragynine, has been reported to be more potent than morphine. Both Kratom alkaloids are reported to activate supraspinal mu- and delta- opioid receptors, explaining their use by chronic narcotics users to ameliorate opioid withdrawal symptoms.

C23H30N2O4

398.4953

398.22

4098-40-2

4098-40-2 (or 6202-22-8);

3034396

White amorphous powder

1.2±0.1 g/cm3

560.3±50.0 °C at 760 mmHg

92-95ºC

292.7±30.1 °C

0.0±1.5 mmHg at 25°C

1.605

3.88

1

5

6

29

624

3

CC[C@@H]1CN2CCC3=C([C@@H]2C[C@@H]1/C(=C\OC)/C(=O)OC)NC4=C3C(=CC=C4)OC

LELBFTMXCIIKKX-QVRQZEMUSA-N

InChI=1S/C23H30N2O4/c1-5-14-12-25-10-9-15-21-18(7-6-8-20(21)28-3)24-22(15)19(25)11-16(14)17(13-27-2)23(26)29-4/h6-8,13-14,16,19,24H,5,9-12H2,1-4H3/b17-13+/t14-,16+,19+/m1/s1

methyl (E)-2-[(2S,3S,12bS)-3-ethyl-8-methoxy-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizin-2-yl]-3-methoxyprop-2-enoate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*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).

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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)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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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).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)