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Stereo, Kekulé, skeletal formula of 7-hydroxymitragynine with an explicit hydrogen added
7-Hydroxymitragynine is a terpenoid indole alkaloid from the plant Mitragyna speciosa, commonly known as Kratom.
Preferred IUPAC name
Methyl (2E)-2-[(2S,3S,7aS,12bS)-3-ethyl-7a-hydroxy-8-methoxy-1,2,3,4,6,7,7a,12b-octahydroindolo[2,3-a]quinolizin-2-yl]-3-methoxyprop-2-enoate
Other names
7α-Hydroxy-7H-mitragynine;[1] 9-Methoxycorynantheidine hydroxyindolenine[1]
3D model (JSmol)
  • InChI=1S/C23H30N2O5/c1-5-14-12-25-10-9-23(27)20-17(7-6-8-19(20)29-3)24-21(23)18(25)11-15(14)16(13-28-2)22(26)30-4/h6-8,13-15,18,27H,5,9-12H2,1-4H3/b16-13+/t14-,15+,18+,23+/m1/s1 checkY
  • CC[C@@H]1CN2CC[C@@]3(O)C(=Nc4cccc(OC)c34)[C@@H]2C[C@@H]1\C(=C/OC)C(=O)OC
  • CC[C@@H]1CN2CC[C@@]3(O)C(=NC4=CC=CC(OC)=C34)[C@@H]2C[C@@H]1\C(=C/OC)C(=O)OC
Molar mass 414.502 g·mol−1
log P 1.266
Acidity (pKa) 12.203
Basicity (pKb) 1.794
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

7-Hydroxymitragynine is a terpenoid indole alkaloid from the plant Mitragyna speciosa, commonly known as Kratom.[2] It is often referred to as ‘7-OH’. It was first described in 1994[3] and is a natural product derived from the mitragynine present in the Kratom leaf. It is considered an oxidized derivative and active metabolite of mitragynine.[4] 7-OH binds to opioid receptors like mitragynine, but research suggests that 7-OH binds with greater potency[5] and contributes heavily to the analgesic activity of mitragynine as a metabolite.[6]



After a kratom study, it was revealed that 7-OH converts into Mitragynine pseudoindoxyl.[7]

Mitragynine Pseudoindoxyl
Mitragyna speciosa alkaloids at opioid receptors
Compound Affinities (Ki) Ratio Ref
7-Hydroxymitragynine 13.5 155 123 1:11:9 [8]
Mitragynine 7.24 60.3 1,100 1:8:152 [8]
Mitragynine pseudoindoxyl 0.087 3.02 79.4 1:35:913 [8]


7-Hydroxymitragynine, like mitragynine, appears to be a mixed opioid receptor agonist/antagonist, acting as a partial agonist at µ-opioid receptors and as a competitive antagonist at δ-opioid receptors, with low affinity for the κ-opioid receptor.[9] Evidence suggests that 7-OH is more potent than both mitragynine and morphine. 7-OH does not activate the β-arrestin pathway like traditional opioids, meaning symptoms such as respiratory depression, constipation and sedation are much less pronounced.[9]

7-OH is generated from mitragynine in vivo by hepatic metabolism and may account for a significant portion of the effects traditionally associated with mitragynine. Although 7-OH occurs naturally in kratom leaves, it does so in such low amounts that any ingested 7-OH is inconsequential compared to the 7-OH generated in the body.[9]

See also[edit]


  1. ^ a b Chemical Abstracts Service: Columbus, OH, 2004; RN 174418-82-7 (accessed via SciFinder Scholar, version 2007.3; November 30, 2011)
  2. ^ Matsumoto K, Horie S, Ishikawa H, Takayama H, Aimi N, Ponglux D, Watanabe K (March 2004). "Antinociceptive effect of 7-hydroxymitragynine in mice: Discovery of an orally active opioid analgesic from the Thai medicinal herb Mitragyna speciosa". Life Sciences. 74 (17): 2143–55. doi:10.1016/j.lfs.2003.09.054. PMID 14969718.
  3. ^ Ponglux, Dhavadee; Wongseripipatana, Sumphan; Takayama, Hiromitsu; Kikuchi, Masae; Kurihara, Mika; Kitajima, Mariko; Aimi, Norio; Sakai, Shin-ichiro (December 1994). "A New Indole Alkaloid, 7 α-Hydroxy-7 H -mitragynine, from Mitragyna speciosa in Thailand". Planta Medica. 60 (6): 580–581. doi:10.1055/s-2006-959578. PMID 17236085.
  4. ^ "7-Hydroxymitragynine - Green Leaf Kratom - Kratom Blogs Archives". Green Leaf Kratom. 2020-08-19. Retrieved 2020-08-22.
  5. ^ Kruegel, Andrew C.; Grundmann, Oliver (15 May 2018). "The medicinal chemistry and neuropharmacology of kratom: A preliminary discussion of a promising medicinal plant and analysis of its potential for abuse". Neuropharmacology. 134 (Pt A): 108–120. doi:10.1016/j.neuropharm.2017.08.026. PMID 28830758. S2CID 24009429.
  6. ^ Spetea, Mariana; Schmidhammer, Helmut (29 May 2019). "Unveiling 7-Hydroxymitragynine as the Key Active Metabolite of Mitragynine and the Promise for Creating Novel Pain Relievers". ACS Central Science. 5 (6): 936–938. doi:10.1021/acscentsci.9b00462. PMC 6598155. PMID 31263752.
  7. ^ Váradi A, Marrone GF, Palmer TC, Narayan A, Szabó MR, Le Rouzic V, Grinnell SG, Subrath JJ, Warner E, Kalra S, Hunkele A, Pagirsky J, Eans SO, Medina JM, Xu J, Pan YX, Borics A, Pasternak GW, McLaughlin JP, Majumdar S (2016). "Mitragynine/Corynantheidine Pseudoindoxyls As Opioid Analgesics with Mu Agonism and Delta Antagonism, Which Do Not Recruit β-Arrestin-2". J. Med. Chem. 59 (18): 8381–97. doi:10.1021/acs.jmedchem.6b00748. PMC 5344672. PMID 27556704.
  8. ^ a b c Takayama, Hiromitsu; Ishikawa, Hayato; Kurihara, Mika; Kitajima, Mariko; Aimi, Norio; Ponglux, Dhavadee; Koyama, Fumi; Matsumoto, Kenjiro; Moriyama, Tomoyuki; Yamamoto, Leonard T.; Watanabe, Kazuo; Murayama, Toshihiko; Horie, Syunji (1 April 2002). "Studies on the Synthesis and Opioid Agonistic Activities of Mitragynine-Related Indole Alkaloids: Discovery of Opioid Agonists Structurally Different from Other Opioid Ligands". Journal of Medicinal Chemistry. 45 (9): 1949–1956. doi:10.1021/jm010576e. PMID 11960505.
  9. ^ a b c Eastlack, Steven C.; Cornett, Elyse M.; Kaye, Alan D. (28 January 2020). "Kratom—Pharmacology, Clinical Implications, and Outlook: A Comprehensive Review". Pain and Therapy. 9 (1): 55–69. doi:10.1007/s40122-020-00151-x. PMC 7203303. PMID 31994019.

Further reading[edit]