Biosynthesis of kratom opioids

Area of Science:

• Biochemistry
• Pharmacology
• Plant Science

Background:

• Mitragynine, an alkaloid from Mitragyna speciosa (kratom), is a potential analgesic alternative to clinical opioids due to its favorable side effect profile.
• Despite traditional use in Southeast Asia for pain and stimulation, the biosynthetic pathway of mitragynine remains uncharacterized.
• Understanding this pathway is crucial for exploring kratom's therapeutic potential and developing novel analgesics.

Purpose of the Study:

• To identify and characterize genes involved in the mitragynine biosynthesis pathway.
• To achieve microbial biosynthesis of mitragynine and its stereoisomer, speciogynine.
• To explore the potential for generating kratom opioid derivatives through enzyme promiscuity.

Main Methods:

• Searched kratom and Rubiaceae family transcriptomes for biosynthetic genes.
• Performed in vitro and in vivo functional studies of identified enzymes.
• Utilized enzymes from various sources, including Psilocybe cubensis and Hamelia patens, to reconstitute the pathway in yeast and E. coli.
• Supplied tryptamine and secologanin as precursors for microbial biosynthesis.

Main Results:

• Identified several reductases and a novel enol methyltransferase within the SABATH family.
• Discovered a methyltransferase from Hamelia patens catalyzing the final step of the pathway.
• Successfully achieved a four-step microbial biosynthesis of mitragynine and speciogynine using heterologous enzymes and microbial hosts.
• Demonstrated enzyme promiscuity, suggesting potential for analog synthesis.

Conclusions:

• The mitragynine biosynthesis pathway has been elucidated, completing our understanding of its formation.
• Microbial biosynthesis of kratom opioids has been achieved for the first time, opening avenues for sustainable production.
• The identified enzymes and pathway provide a foundation for developing novel kratom-derived analgesics and exploring their therapeutic applications.