UV irradiation does a solid job of oxidation of mitragynine..
I wrote up a kitchen chemistry tek awhile back for wholesale conversion of mitragynine to 7-oh-mitragynine, but I'm not going to rewrite it all here.
Very summed up, you can utilize 35% H2O2 for a few hours, then hit with heavy UV-A/B/C radiation for a day or two and convert about 80% of the mitragynine to 7-oh-mitragynine. If you want me to post the whole tek which would take me hours to write out again from years ago, you gotta give me a lot of time, lol.
Without growth, what's the point?
Avid gardener and Ethnobotany enthusiast