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Todd DA, Kellogg JJ, Wallace ED, Khin M, Flores-Bocanegra L, Tanna RS, McIntosh S, Raja HA, Graf TN, Hemby SE, Paine MF, Oberlies NH, Cech NB. Chemical composition and biological effects of kratom (Mitragyna speciosa): In vitro studies with implications for efficacy and drug interactions. Sci Rep 2020; 10:19158. [PMID: 33154449 PMCID: PMC7645423 DOI: 10.1038/s41598-020-76119-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/22/2020] [Indexed: 01/24/2023] Open
Abstract
The safety and efficacy of kratom (Mitragyna speciosa) for treatment of pain is highly controversial. Kratom produces more than 40 structurally related alkaloids, but most studies have focused on just two of these, mitragynine and 7-hydroxymitragynine. Here, we profiled 53 commercial kratom products using untargeted LC-MS metabolomics, revealing two distinct chemotypes that contain different levels of the alkaloid speciofoline. Both chemotypes were confirmed with DNA barcoding to be M. speciosa. To evaluate the biological relevance of variable speciofoline levels in kratom, we compared the opioid receptor binding activity of speciofoline, mitragynine, and 7-hydroxymitragynine. Mitragynine and 7-hydroxymitragynine function as partial agonists of the human µ-opioid receptor, while speciofoline does not exhibit measurable binding affinity at the µ-, δ- or ƙ-opioid receptors. Importantly, mitragynine and 7-hydroxymitragynine demonstrate functional selectivity for G-protein signaling, with no measurable recruitment of β-arrestin. Overall, the study demonstrates the unique binding and functional profiles of the kratom alkaloids, suggesting potential utility for managing pain, but further studies are needed to follow up on these in vitro findings. All three kratom alkaloids tested inhibited select cytochrome P450 enzymes, suggesting a potential risk for adverse interactions when kratom is co-consumed with drugs metabolized by these enzymes.
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Affiliation(s)
- D A Todd
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - J J Kellogg
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
- Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| | - E D Wallace
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
- Department of Chemistry, The University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA
| | - M Khin
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - L Flores-Bocanegra
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - R S Tanna
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA
| | - S McIntosh
- Department of Basic Pharmaceutical Sciences, High Point University, High Point, NC, 27268, USA
| | - H A Raja
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - T N Graf
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - S E Hemby
- Department of Basic Pharmaceutical Sciences, High Point University, High Point, NC, 27268, USA
| | - M F Paine
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA
| | - N H Oberlies
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - N B Cech
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA.
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