7-Hydroxymitragynine

7-Hydroxymitragynine (7-OH) is a terpenoid indole alkaloid from the plant Mitragyna speciosa, commonly known as kratom.^[2] It was first described in 1994^[3] and is a human metabolite metabolized from mitragynine present in the Mitragyna speciosa. 7-OH binds to opioid receptors like mitragynine, but research suggests that 7-OH binds with greater efficacy.^[4]

7-Hydroxymitragynine

Clinical data
Other names	7α-Hydroxy-7H-mitragynine;[1] 9-Methoxycorynantheidine hydroxyindolenine[1]
Routes of administration	By mouth
Drug class	Opioid
ATC code	None
Legal status
Legal status	BR: Class F1 (Prohibited narcotics) US: Unscheduled
Pharmacokinetic data
Metabolites	Mitragynine pseudoindoxyl
Identifiers
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
CAS Number	174418-82-7 N
PubChem CID	44301524
ChemSpider	23152144 Y
UNII	2T3TWA75R0
ChEMBL	ChEMBL61630 Y
CompTox Dashboard (EPA)	DTXSID20903988
Chemical and physical data
Formula	C23H30N2O5
Molar mass	414.502 g·mol−1
3D model (JSmol)	Interactive image Interactive image
SMILES 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
InChI 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 Y Key:RYENLSMHLCNXJT-CYXFISRXSA-N Y

7-Hydroxymitragynine (7-OH), a metabolite of the psychoactive botanical kratom, exhibits significantly higher binding affinity to mu-opioid receptors (MOR) than morphine, with estimates ranging from 14 to 22 times greater potency. Although kratom's primary alkaloid, mitragynine, is associated with lower abuse potential and moderate safety, 7-OH demonstrates opioid-like effects and can substitute for morphine in a dose-dependent manner, raising concerns about its potential for physical dependence and addiction.^[5]

Recent developments in the market have introduced semi-synthetic 7-OH products, which differ from traditional kratom preparations in both concentration and route of administration. These novel products often contain up to 98% 7-OH and are marketed in formulations such as sublingual tablets/strips or also powders. Some of these formulations bypass first-pass metabolism, significantly increasing bioavailability and potentially amplifying their opioid-like effects.^[6]

Pharmacology

7-Hydroxymitragynine, like mitragynine, appears to be a mixed opioid receptor agonist/antagonist, with recent research indicating that it acts as a partial agonist at μ-opioid receptors and as a competitive antagonist at δ- and κ-opioid receptors.^[7][8] 7-OH does not appear to activate the β-arrestin pathway, distinguising it from traditional opiate & opioid chemicals.^[7] It shares this trait with mitragynine.

References

1. 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): 2143–2155. doi:10.1016/j.lfs.2003.09.054. PMID 14969718.
3. Ponglux D, Wongseripipatana S, Takayama H, Kikuchi M, Kurihara M, Kitajima M, et al. (December 1994). "A New Indole Alkaloid, 7 alpha-Hydroxy-7H-mitragynine, from Mitragyna speciosa in Thailand". Planta Medica. 60 (6): 580–581. doi:10.1055/s-2006-959578. PMID 17236085. S2CID 260252538.
4. Kruegel AC, Grundmann O (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.
5. Smith KE, Boyer EW, Grundmann O, McCurdy CR, Sharma A (2024). "The rise of novel, semi-synthetic 7-hydroxymitragnine products". Addiction. doi:10.1111/add.16728. PMID 39627873.
6. Smith KE, Boyer EW, Grundmann O, McCurdy CR, Sharma A (2024). "The rise of novel, semi-synthetic 7-hydroxymitragnine products". Addiction. doi:10.1111/add.16728. PMID 39627873.
7. Eastlack SC, Cornett EM, Kaye AD (June 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.
8. Chang-Chien GC, Odonkor CA, Amorapanth P (2017). "Is Kratom the New 'Legal High' on the Block?: The Case of an Emerging Opioid Receptor Agonist with Substance Abuse Potential". Pain Physician. 20 (1): E195 – E198. doi:10.36076/ppj.2017.1.E195. PMID 28072812.