Help me with some simple rxns involving heating kratom

[gingerbaker]

So, my question is fairly simple (for you all) and involves the rxns that occur during boiling kratom leaves. There is much speculation about what effect this has on several prominent alkaloids, but I am curious if some of the brilliant minds here can give me some definitive answers.

When kratom leaves are boiled at a rolling boil, what happens to Mitragynine (which is the most prominent alkaloid by mass @ 66%)?


and
7-Hydroxymitragynine


Also, for those familiar with the makeup of some of the other alkaloids what happens to Kratom when exposed to 100C for, say 30min?

I think the alkaloids mentioned above are the most important from a MOR agonism point of view, but are there any other rxns that would be significant in changing the pharmacologic action of kratom?

Thanks.

 

[gingerbaker]

Also, is there any good reason to include lemon/orange/lime juice when making the tea? Apparently "it helps release the alkaloids" and "helps extract the alkaloids more" but I'm wondering if there is any truth behind this. Does it have anything to do with converting it to a citrate which might be more BA?

 

[sekio]

Boiling kratom for any length of time will probably destroy some of the alkaloids through hydrolysis, because they have a fairly labile methyl ester group. This is easily observed by comparing fresh kratom leaf to "kratom extract" prepared by boiling kratom tea down. 9 times out of 10, it is woefully inactive. Kratom tea also probably doesn't store well (I've never tried).

I wouldn't be surprised if prolonged, high-temperature boiling would also isomerize the double bond. Possibly the enol ether could also be broken if there is enough acidity.

7-hydroxymitragynine could also undergo dehydration to a much less active compound (not shown). There is also the possibility of amine N-oxide formation (also not shown).

Keeping conditions as close to neutral as possible as well as minimizing boiling time will get you best results.