Chemical Structures (Appendix)

Structure diagrams for morphine, the kratom leaf alkaloids, and the concentrated and semi-synthetic mitragynine derivatives that drive the 7-OH product market.

This is a visual appendix for the Minor Alkaloids and Morphine vs. Mitragyna Alkaloids reference pages. Each diagram is a 2D skeletal-formula representation of the molecule discussed on those pages. The pharmacology and clinical context lives on the main pages; this one is just the structures.

If chemical structures aren’t what you came here for, the main pharmacology pages cover everything in words and tables. The structures below are for readers who want to see what the alkaloids look like at the molecular level, and how 7-OH and the semi-synthetic derivatives (MGM-15, pseudo) relate to plain mitragynine structurally.

Native kratom leaf alkaloids

Chemical structure of mitragynine — Mitragynine
Reference alkaloid · partial µ-agonist

Chemical structure of paynantheine — Paynantheine
Usually 2nd most abundant · 5-HT₁ₐ activity

Chemical structure of speciogynine — Speciogynine
C-20 diastereomer · weak µ-antagonist + 5-HT₁ₐ

Chemical structure of speciociliatine — Speciociliatine
C-3 diastereomer · partial µ-agonist, higher affinity

Chemical structure of corynantheidine — Corynantheidine
µ-opioid antagonist · α-1D-selective

Chemical structure of 9-hydroxycorynantheidine — 9-Hydroxycorynantheidine
9-OH restores µ-agonism

Chemical structure of mitraphylline — Mitraphylline
Oxindole alkaloid · poorly characterized

Concentrated and semi-synthetic mitragynine derivatives

These are the structurally-modified compounds that drive the 7-OH product market and the stacked synthetics. Each is one or two atom-level changes away from plain mitragynine, and those changes can shift µ-opioid receptor affinity by orders of magnitude.

Chemical structure of 7-hydroxymitragynine — 7-Hydroxymitragynine (7-OH)
–OH at C-7 · large µ-affinity jump vs. mitragynine

Chemical structure of 7-acetoxymitragynine — 7-Acetoxymitragynine
Acetate ester · hydrolyzes back to 7-OH

Chemical structure of dihydro-7-hydroxymitragynine (MGM-15) — Dihydro-7-hydroxymitragynine (MGM-15)
7-OH + saturated indolenine · tightest receptor fit

Chemical structure of pseudoindoxyl mitragynine — Pseudoindoxyl mitragynine
Oxidative rearrangement · carbonyl H-bond acceptor

Reference

Chemical structure of morphine — Morphine
Phenanthrene-class opioid · NOT a mitragynine derivative

Morphine shares the µ-opioid receptor with mitragynine and its derivatives, but it isn’t structurally related to them, it’s from a completely different alkaloid family. It’s included on this site because clinical practice often references morphine for relative potency comparisons; see Morphine vs. Mitragyna Alkaloids for the affinity comparison and what the structural differences do.

Reference, not advice. Structures are 2D skeletal-formula representations rendered from cheminformatics data. They don’t tell you anything about what to take or how to taper, those decisions belong with a clinician familiar with your situation.

Where to read next

Minor Alkaloids: receptor activity of the seven native kratom alkaloids across the µ-opioid, serotonergic, and adrenergic systems
Morphine vs. Mitragyna Alkaloids , what each structural modification does to µ-opioid receptor affinity
Compounds: the clinical / lay overviews of each named compound on this site