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
…Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze… Quantitative analysis of mitral alkaloids in plasma samples from rats (n=8 at each sampling time point) after a single oral dose of 20 mg/kg was performed. The obtained pharmacokinetic parameters (mean values) are as follows: peak plasma concentration: 424 ng/mL; time to peak concentration: 1.26 h; elimination half-life: 3.85 h; apparent total clearance: 6.35 L/hr/kg; apparent volume of distribution: 37.90 L/kg. Metabolites/Metabolites Mitragynine is a drug of abuse. Several alkaloids and their metabolites must be considered when monitoring its abuse in urine. In previous studies, salicylic acid (MG), its diastereomer salicylic acid (SG), penamine, and their metabolites were identified in rat and human urine using liquid chromatography-tandem mass spectrometry (LC-MS(n)). In the urine of kratom users, other isomers besides MG and SG were detected. To clarify whether the diastereomer salicylic acid (SC) of MG and SG and its metabolites represent other compounds, the phase I and II metabolites of SC were first identified in rats after administration of pure alkaloids. Then, the identified rat metabolites were screened in the urine of kratom users using the aforementioned LC-MS(n) method. Combining mass spectra and retention times, it was confirmed that SC and its metabolites are isomers not previously identified in human urine. In conclusion, SC and its metabolites can serve as further markers for kratom use, particularly applicable to the consumption of raw materials or products containing high amounts of the fruit of the Malaysian plant M. speciosa. This study aimed to identify phase I and II metabolites of cratomycin (MG) in rat and human urine using liquid chromatography-linear ion trap mass spectrometry (LC-LINEMS) via solid-phase extraction (SPE), providing detailed structural information, particularly at high resolution, in MSn mode. The identification of seven phase I metabolites indicates that the metabolic pathway of MG includes: hydrolysis of the 16-methyl ester, O-demethylation of the 9-methoxy and 17-methoxy groups, followed by oxidation of the intermediate aldehyde to a carboxylic acid or reduction to an alcohol, and combinations of certain steps. In rats, four metabolites were additionally bound to glucuronide, and one to sulfate; while in humans, three metabolites were bound to glucuronide, and three to sulfate. In studies of the major cratomycin alkaloid MG in rats and humans, several dehydrogenated analogues were detected in the urine of cratomycin users, whereas these analogues were not found in the urine of rats after administration of pure MG. This raises the question: are these compounds produced solely by the metabolism of MG in the human body, or by the metabolism of planannin (PAY), the second major alkaloid of kratom? Therefore, this study aimed to identify the Phase I and Phase II metabolites in the urine of rats after administration of the pure alkaloid PAY, which was initially isolated from kratom leaves. Liquid chromatography-linear ion trap mass spectrometry in MS(n) mode, particularly at high resolution, provided detailed structural information of the metabolites. In addition to PAY, the following Phase I metabolites were 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 indicate that PAY's metabolic pathway is the same as that of MG. Some metabolites are excreted as glucuronides or sulfates. Rat metabolic studies have shown that PAY and its metabolites correspond to MG-related dehydrogenases detected in the urine of Kratom users. In conclusion, in addition to MG and its metabolites, PAY and its metabolites may also be further biomarkers of Kratom abuse.

Interactions
MG (Mitragynine Korth) is the main alkaloid extracted from the plant Mitragynine Korth, and is known to have opioid-like activities. Previous studies have shown that the opioid system is involved in the analgesic activity of MG in the tail clip and hot plate tests in mice. In this study, to elucidate the opioid receptor subtypes involved in the analgesic effect of MG, we investigated the effects of selective μ, δ, and κ opioid receptor antagonists on the analgesic effect induced by intraventricular (ICV) injection of MG in the tail clip and hot plate tests in mice. Co-administration of the selective μ-opioid receptor antagonist cyprodinil (1–10 μg, ICV) with the selective μ1-opioid receptor antagonist naloxone (1–3 μg, ICV) significantly antagonized the analgesic effects of MG (10 μg, ICV) and morphine (MOR, 3 μg, ICV) in the tail clip and hot plate tests. The selective delta-opioid receptor antagonist naltrexindole (1–5 ng, intraventricular injection) also blocked the effects of MG (10 μg, intraventricular injection) but did not affect the analgesic effect of MOR (3 μg, intraventricular injection). The selective κ-opioid receptor antagonist norbinaltorphimine significantly attenuated the analgesic effect of intraventricularly administered (icV) MG in the tail clip test, but this was not observed in the hot plate test. This dose (1 μg, icV) had the same analgesic effect as the selective κ-opioid receptor agonist U50,488H in both tests. However, norbinaltorphimine had no effect on the analgesic effect of μ-opioid receptor (MOR) in either test. These results indicate that the analgesic effect induced by intraventricularly administered MG is primarily mediated by μ and delta-opioid receptor subtypes, and that the selectivity of MG for spinal opioid receptor subtypes differs from the selectivity 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. It has been found in the tree Mitragynine, and data on its effects have been reported. Mechanism of Action: ...Mitragynine (MIT) is a μ-opioid receptor agonist with analgesic and antitussive effects... Mitragynine is the major alkaloid of kratom and has been reported as a partial opioid receptor agonist, producing effects similar to morphine. An interesting minor alkaloid in kratom—7-hydroxyMitragynine—has been reported to be more potent than morphine. Both kratom alkaloids are reported to activate μ- and δ-opioid receptors in the spinal cord, which explains why long-term addicts use them to alleviate 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.)