Isolation of Ibogaine from Tabernanthe iboga
from J Amer. Chem. soc #80: 123, 1958.
In this case it was for the root/root bark of tabernanthe iboga used as the plant material, which may contain up to 2.5 % or 6 % alkaloids respectively. The plant material was extracted with methanol four times, filtered and the methanol reduced to a small volume. An equal amount of water and acetic acid solution is added and shaken with petroleum naphtha, which is then separated and backwashed with acetic acid solution.
All the aqueous phases are combined. The aqueous phases are reduced in volume, then basified with ammonia hydroxide. This is then extracted four times with ethylene dichloride (possibly chloroform too). The solvent is washed with water, dried and concentrated. An equal amount of ethanol is added and the whole reduced to the original volume, then about twice the amount of ethanol is added. After chilling in the fridge for two days or so, ibogaine crystallises out, and can be collected by filtration. The remaining liquid was again reduced in volume and re-chilled for a second crop of ibogaine.
Evaporation to dryness of the liquid yielded other alkaloids and residual ibogaine, which can be separated by chromatography, though can be laborious. To purify the ibogaine 100 mg of the crude ibogaine, as obtained above, was dissolved in 1 l of acetone, then 53.1 ml of 1:1 HCl was added, with ibogaine HCl precipitating (108 mg in this case) out straight away, this compound being relatively insoluble in acetone, compared to the base. Isolated by filtration.
ibogaine mp 151-153* C sol - ethanol, ether, chloroform, acetone
ibogaine HCl mp 299-300* C.
In tabernanthe iboga, ibogaine seems to be the most active and prominent alkaloid. In other species that are recorded as containing ibogaine, other alkaloids sometimes make up the majority of the alkaloids, with ibogaine being a minor component. Many related alkaloids however have a similar but not such strong action as ibogaine. The isolation of ibogaine from more complex mixtures of alkaloids may be a bit more tricky, especially if ibogaine is not a major component of the alkaloids.