Psychoactive Plant Database - Neuroactive Phytochemical Collection

1. Chem Biol Interact. 2024 Oct 10;404:111264. doi: 10.1016/j.cbi.2024.111264. 
Online ahead of print.

Binding characteristics of the major kratom alkaloid, mitragynine, towards serum 
albumin: Spectroscopic, calorimetric, microscopic, and computational 
investigations.

Bakar KA(1), Lam SD(2), Feroz SR(3).

Author information:
(1)Department of Biological Sciences and Biotechnology, Faculty of Science and 
Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
(2)Department of Applied Physics, Faculty of Science and Technology, Universiti 
Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia; Structural Biology and 
Protein Engineering Group, Universiti Kebangsaan Malaysia, 43600, Bangi, 
Selangor, Malaysia; Center for Global Health Research (CGHR), Saveetha Medical 
College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha 
University, Chennai, India.
(3)Department of Biological Sciences and Biotechnology, Faculty of Science and 
Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia; 
Structural Biology and Protein Engineering Group, Universiti Kebangsaan 
Malaysia, 43600, Bangi, Selangor, Malaysia. Electronic address: 
shevin@ukm.edu.my.

Mitragynine (MTG) is a prominent indole alkaloid that is present abundantly in 
Mitragyna speciosa, commonly referred to as kratom. MTG has garnered significant 
attention due to its selective agonistic characteristics towards opioid 
receptors and related analgesic effects. In the circulatory system, the in vivo 
efficacy of MTG is dictated by its interaction with plasma proteins, primarily 
human serum albumin (HSA). In the present study, we utilized a broad methodology 
that included spectroscopic, calorimetric, microscopic, and in silico approaches 
to characterize the interaction between MTG and HSA. Alterations in the UV 
absorption spectrum of HSA by the presence of MTG demonstrated a ground-state 
complexation between the protein and the ligand. The Ka values obtained for the 
MTG-HSA interaction were in the range 103-104 M-1 based on analysis of 
fluorescence and ITC data, respectively, indicating an intermediate binding 
affinity. The binding reaction was thermodynamically favorable as revealed by 
ΔH, ΔS, and ΔG values of -16.42 kJ mol-1, 39.97 J mol-1 K-1, and 
-28.34 kJ mol-1, respectively. Furthermore, CD spectroscopy results suggested 
MTG binding induced minimal effects on the structural integrity of HSA, 
supported by computational methods. Changes in the dimensions of HSA particles 
due to aggregation, as observed using atomic force microscopy in the presence of 
MTG. Competitive drug displacement results seemingly suggested site III of HSA 
located at subdomain IB as the preferred binding site of MTG, but were in 
inconclusive. However, docking results showed the clear preference of MTG to 
bind to site III, facilitated by hydrophobic (alkyl and pi-alkyl) and van der 
Waals forces, together with carbon hydrogen bonds. Additionally, the MTG-HSA 
complexation was demonstrated to be stable based on molecular dynamics analysis. 
The outcomes of this study shed light on the therapeutic potential of MTG and 
can help in the design of more effective derivatives of the compound.

Copyright © 2024 Elsevier B.V. All rights reserved.

DOI: 10.1016/j.cbi.2024.111264
PMID: 39393752

Conflict of interest statement: Declaration of competing interest The authors 
declare that they have no known competing financial interests or personal 
relationships that could have appeared to influence the work reported in this 
paper.


2. Phytochem Anal. 2024 Aug 28. doi: 10.1002/pca.3442. Online ahead of print.

Rapid mitragynine quantification and fingerprinting of products from Mitragyna 
speciosa Korth. leaf (Kratom) using high-performance thin-layer chromatography.

Hayeema T(1), Wungsintaweekul J(1).

Author information:
(1)Department of Pharmacognosy and Pharmaceutical Botany, Faculty of 
Pharmaceutical Sciences, Prince of Songkla University, Hat Yai Campus, Songkhla, 
Thailand.

INTRODUCTION: Kratom (leaves from Mitragyna speciosa Korth.; Rubiaceae) is a 
herbal medicine known for its analgesic properties and psychoactive effects. 
Kratom in Thailand is currently legal; however, it is prohibited in some 
countries and considered a narcotic plant.
OBJECTIVE: Our aim was to establish a reliable, simple, and rapid method for 
quantifying mitragynine in Kratom leaves and related products through a 
combination of high-performance thin-layer chromatography (HPTLC) and 
densitometry.
METHODOLOGY: A densitometric HPTLC method was developed and validated in terms 
of specificity, linearity, limit of detection (LOD), limit of quantification 
(LOQ), accuracy, precision, and robustness. The fingerprints of kratom leaves, 
Mitragyna spp., and related products were constructed.
RESULTS: For HPTLC, samples were applied to silica gel 60 F254 plates, and the 
mobile phase comprised n-hexane, ethyl acetate, and triethylamine (1:1:0.15, 
v/v/v). Densitometric detection was carried out under ultraviolet light at a 
wavelength of 226 nm. The validated method exhibited a range of 
14.31-143.10 μg/mL, yielding a correlation coefficient of 0.9993. Spiked 
recovery rates were within a range of 98.3%-100.9%, and the LOD and LOQ were 
3.80 and 11.53 μg/mL, respectively. Kratom samples were analyzed with the 
developed method, and the correlation coefficient was 0.9641, compared to the 
high-performance liquid chromatography-diode-array detection (HPLC-DAD) method. 
The HPTLC fingerprints displayed a distinctive pattern, facilitating 
discrimination among different plant parts and Mitragyna spp.
CONCLUSION: The established method offers the advantages of simplicity, ease of 
use, and speed of analysis, serving as a practical alternative for mitragynine 
quantification in kratom leaf and its related products.

© 2024 John Wiley & Sons Ltd.

DOI: 10.1002/pca.3442
PMID: 39193915


3. Magn Reson Chem. 2024 Nov;62(11):803-813. doi: 10.1002/mrc.5477. Epub 2024 Aug
 27.

Quantitative analysis of selected alkaloids of Mitragyna speciosa using (1)H 
quantitative nuclear magnetic resonance spectroscopy.

Garba SA(1)(2), Shaari K(1), Abdul Manap MR(3), Lee SY(4)(5), Abdulazeez I(6), 
Mohd Faudzi SM(1)(3).

Author information:
(1)Natural Medicines and Products Research Laboratory, Institute of Bioscience, 
Universiti Putra Malaysia, Serdang, Malaysia.
(2)Chemistry Department, Faculty of Natural and Applied Sciences, Sule Lamido 
University, Kafin Hausa, Nigeria.
(3)Department of Chemistry, Faculty of Sciences, Universiti Putra Malaysia, 
Serdang, Malaysia.
(4)School of Food Studies & Gastronomy, Faculty of Social Sciences & Leisure 
Management, Taylor's University, Subang Jaya, Malaysia.
(5)Food Security & Nutrition Impact Lab, Taylor's University, Subang Jaya, 
Selangor, Malaysia.
(6)Chemistry Department, School of Secondary Education Sciences, Federal College 
of Education Zaria, Tudun Wada, Nigeria.

Mitragyna speciosa is a perennial plant native to Asia, well known for its 
psychoactive properties. Its major alkaloid mitragynine is known to have 
sedative and euphoric effects. Hence, the plant has been a subject of abuse, 
leading to addiction, necessitating efficient analytical methods to detect its 
psychoactive constituents. However, current chromatography-based methods for 
detecting the alkaloids are time consuming and costly. Quantitative nuclear 
magnetic resonance (qNMR) spectroscopy emerges as a promising alternative due to 
its nondestructive nature, structural insights, and short analysis time. Hence, 
a rapid and precise qNMR method was developed to quantify selected major 
psychoactive alkaloids in various parts of M. speciosa. Mitragynine, 
specioliatine, and speciogynine were quantified in relation to the integral 
value of the -OCH3 groups of the alkaloids and the internal standard 
1,4-dinitrobenzene. The precision and reproducibility of the method gave a 
relative standard deviation (RSD) of 2%, demonstrating the reliability of the 
method. In addition, the method showed excellent specificity, sensitivity, high 
linearity range (R2 = 0.999), and limits of detection (LOD) and quantification 
(LOQ) values. The analysis revealed that the red-veined M. speciosa leaves 
contained higher levels of mitragynine (32.34 mg/g), specioliatine (16.84 mg/g) 
and speciogynine (7.69 mg/g) compared to the green-veined leaves, stem bark, or 
fruits.

© 2024 John Wiley & Sons Ltd.

DOI: 10.1002/mrc.5477
PMID: 39189504 [Indexed for MEDLINE]


4. ACS Pharmacol Transl Sci. 2024 Jul 25;7(8):2452-2464. doi: 
10.1021/acsptsci.4c00277. eCollection 2024 Aug 9.

Multiple-Dose Pharmacokinetics and Safety of Mitragynine, the Major Alkaloid of 
Kratom, in Rats.

Chiang YH(1), Berthold EC(1), Kuntz MA(1), Kanumuri SRR(1)(2), Senetra AS(1), 
Mukhopadhyay S(3), Hampson AJ(4), McCurdy CR(2)(3), Sharma A(1)(2).

Author information:
(1)Department of Pharmaceutics, College of Pharmacy, University of Florida, 
Gainesville, Florida 32610, United States.
(2)Translational Drug Development Core, Clinical and Translational Science 
Institute, University of Florida, Gainesville, Florida 32610, United States.
(3)Department of Medicinal Chemistry, College of Pharmacy, University of 
Florida, Gainesville, Florida 32610, United States.
(4)Division of Therapeutics and Medical Consequences, National Institute on Drug 
Abuse, National Institutes of Health, Bethesda, Maryland 20892, United States.

This study reports the steady-state pharmacokinetic parameters for mitragynine 
and characterizes its elimination in male and female rats. Four male and female 
rats were dosed q12h with 40 mg/kg, and orally administered mitragynine for 5 
and 6 days, respectively. Using a validated ultraperformance liquid 
chromatography-tandem mass spectrometry (UPLC-MS/MS) method, the plasma 
concentrations of mitragynine, its metabolites (7-hydroxymitragynine, 
9-hydroxycorynantheidine, and mitragynine acid), and a non-CYP oxidation product 
(3-dehydromitragynine) were determined at various time points. Sex differences 
in pharmacokinetics were observed, with females demonstrating significantly 
higher systemic exposure of mitragynine than males. The mitragynine area under 
the curve normalized by the dose interval (AUC/τ) was 6741.6 ± 869.5 h*ng/mL in 
female rats and 1808.9 ± 191.3 h*ng/mL in males (p < 0.05). Both sexes produced 
similar metabolite profiles; the major metabolites were mitragynine acid and 
9-hydroxycorynantheidine. 7-Hydroxymitragynine was a minor metabolite. However, 
higher exposure (AUCs) and the maximum plasma concentrations (C max) of active 
metabolites, 7-hydroxymitragynine and 9-hydroxycorynantheidine, were observed in 
female rats and exhibited substantial sex differences. Renal clearance of 
mitragynine (CLr) was low (0.64 ± 0.3 mL/h in males and 0.98 ± 0.4 mL/h in 
females), and unchanged mitragynine accounted for <1% of the dose excreted in 
feces (both sexes). The clinical chemistry, complete blood count, and 
hematological test results reported no abnormal hematological findings after 
multiple dosing in either sex.

© 2024 American Chemical Society.

DOI: 10.1021/acsptsci.4c00277
PMCID: PMC11320740
PMID: 39144552

Conflict of interest statement: The authors declare no competing financial 
interest.


5. Eur J Pharmacol. 2024 Oct 5;980:176863. doi: 10.1016/j.ejphar.2024.176863.
Epub  2024 Jul 26.

The Mitragyna speciosa (kratom) alkaloid mitragynine: Analysis of adrenergic 
α(2) receptor activity in vitro and in vivo.

Obeng S(1), Crowley ML(2), Mottinelli M(2), León F(2), Zuarth Gonzalez JD(3), 
Chen Y(4), Gamez-Jimenez LR(3), Restrepo LF(3), Ho NP(3), Patel A(3), Martins 
Rocha J(3), Alvarez MA(3), Thadisetti AM(3), Park CR(3), Pallares VLC(3), Milner 
MJ(3), Canal CE(4), Hampson AJ(5), McCurdy CR(6), McMahon LR(3), Wilkerson 
JL(7), Hiranita T(8).

Author information:
(1)Department of Medicinal Chemistry, College of Pharmacy, University of 
Florida, Gainesville, FL, 32610, USA; Department of Pharmacodynamics, College of 
Pharmacy, University of Florida, Gainesville, FL, 32610, USA.
(2)Department of Medicinal Chemistry, College of Pharmacy, University of 
Florida, Gainesville, FL, 32610, USA.
(3)Department of Pharmacodynamics, College of Pharmacy, University of Florida, 
Gainesville, FL, 32610, USA.
(4)Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, 
Atlanta, GA, 30341, USA.
(5)Division of Therapeutics and Medical Consequences, National Institute on Drug 
Abuse, National Institutes of Health, Bethesda, MD, 20892, USA.
(6)Department of Medicinal Chemistry, College of Pharmacy, University of 
Florida, Gainesville, FL, 32610, USA; Department of Pharmaceutics, University of 
Florida, Gainesville, FL 32610, USA; Translational Drug Development Core, 
Clinical and Translational Sciences Institute, College of Pharmacy, University 
of Florida, Gainesville, FL, 32610, USA.
(7)Department of Pharmacodynamics, College of Pharmacy, University of Florida, 
Gainesville, FL, 32610, USA. Electronic address: Jenny.Wilkerson@ttuhsc.edu.
(8)Department of Pharmacodynamics, College of Pharmacy, University of Florida, 
Gainesville, FL, 32610, USA. Electronic address: hiranita@uthscsa.edu.

Mitragynine, an alkaloid present in the leaves of Mitragyna speciosa (kratom), 
has a complex pharmacology that includes low efficacy agonism at μ-opioid 
receptors (MORs). This study examined the activity of mitragynine at adrenergic 
α2 receptors (Aα2Rs) in vitro and in vivo. Mitragynine displaced a radiolabeled 
Aα2R antagonist ([3H]RX821002) from human Aα2ARs in vitro with lower affinity 
(Ki = 1260 nM) than the agonists (-)-epinephrine (Ki = 263 nM) or lofexidine 
(Ki = 7.42 nM). Mitragynine did not significantly stimulate [35S]GTPγS binding 
at Aα2ARs in vitro, but in rats trained to discriminate 32 mg/kg mitragynine 
from vehicle (intraperitoneally administered; i.p.), mitragynine exerted an Aα2R 
agonist-like effect. Both α2R antagonists (atipamezole and yohimbine) and MOR 
antagonists (naloxone and naltrexone) produced rightward shifts in mitragynine 
discrimination dose-effect function and Aα2R agonists lofexidine and clonidine 
produced leftward shifts. In the mitragynine trained rats, Aα2R agonists also 
produced leftward shifts in discrimination dose-effect functions for morphine 
and fentanyl. In a separate rat cohort trained to discriminate 3.2 mg/kg i.p. 
morphine from vehicle, naltrexone produced a rightward shift, but neither an 
Aα2R agonist or antagonist affected morphine discrimination. In a hypothermia 
assay, both lofexidine and clonidine produced marked effects antagonized by 
yohimbine. Mitragynine did not produce hypothermia. Together, these data 
demonstrate that mitragynine acts in vivo like an Aα2R agonist, although its 
failure to induce hypothermia or stimulate [35S]GTPγS binding in vitro, suggests 
that mitragynine maybe a low efficacy Aα2R agonist.

Copyright © 2024 Elsevier B.V. All rights reserved.

DOI: 10.1016/j.ejphar.2024.176863
PMID: 39068978 [Indexed for MEDLINE]

Conflict of interest statement: Declaration of competing interest The authors 
declare that they have no known competing financial interests or personal 
relationships that could have appeared to influence the work reported in this 
paper.