Hey guys. Just did some research on extraction and made this little write-up. Posted in another thread previously but though I'd add it to the big one.
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The strong opioid effects of kratom are caused by a complex combination of alkaloids present in the plant. The most important is 7-hydroxymitragynine (7-OH-m) which has been shown to be stronger than morphine by at least a factor of 10. Pseudoindoxyl mitragynine is three fold stronger than 7-OH-m, but is not present in large enough amounts to be considered, and mitragynine, though by far the most abundant alkaloid, is merely similar in strength to morphine and any effects are likely overshadowed by the more powerful 7-OH-m. (Takayama et al, 2002)
A study was undertaken by Kikura-Hanajiri et al to present a method of determining the alkaloid content of commercially available kratom products. Part of this method included the optimal extraction of the alkaloids from the plant matter. The extraction somewhat focused on 7-OH-m as it was considered the best indicator of potential for abuse. The final extraction procedure is as follows.
Step 1: grind the kratom into as fine a powder as possible
Step 2: add kratom to 80% methanol solution
Step 3: mix solution for several hours (ultrasonification)
Step 4: store at room temperature overnight
Step 5: filter solution (centrifuge)
Some parts of this procedure are commonsense, for example the finer the powder the better and there is no real disadvantage to mixing for longer periods of time. The most important part is the choice of 80% methanol for the solvent. Regarding the solvent chemical, ethanol, methanol and acetonitrile were all tested with methanol clearly being the best choice. Due to methanol's toxicity, it is worthwhile to mention that ethanol was a third less effective than methanol.
As for the methanol concentration, it was found that the amount of 7-OH-m extracted at 80% was double that extracted at 100% and also double that extracted at 50%. Interestingly the mitragynine extracted was the same for all concentrations in that range. (Kikura-Hanajiri et al, 2009)
In summary if you are attempting to do an extraction on kratom do so with a 70-80 percent methanol solution.
REFERENCES
Simultaneous analysis of mitragynine, 7-hydroxymitragynine, and other alkaloids in the psychotropic plant “kratom” (Mitragyna speciosa) by LC-ESI-MS
Kikura-Hanajiri et al
Forensic Toxicology (2009)
accessed Feb/2011:
http://www.springerlink.com/content/y81p24x5u1x00962/
Studies on the Synthesis and Opioid Agonistic Activities of Mitragynine-Related Indole Alkaloids: Discovery of Opioid Agonists Structurally Different from Other Opioid Ligands
Takayama et al
Journal of Medicinal Chemistry (2002)
accessed Feb/2011:
http://pubs.acs.org/doi/abs/10.1021/jm010576e