Khat
Catha edulis is a flowering evergreen shrub cultivated in East Africa and the Arabian Peninsula. The leaves and fresh shoots are commonly known as khat, qat or chat. Khat can be used by chewing the leaves or by brewing them as a ‘tea’; daily consumption can be up to several hundred grams. It is typically imported into Europe and the US with the stems tied into bundles (Fig. 1). Khat has stimulant effects similar to those of amfetamine. Alcoholic extracts (tinctures) of khat have been noted, especially in ‘Herbal High’ sales outlets and at music festivals.
The active components of khat, cathinone ((S)-2-amino-1-phenyl-1-propanone) and cathine ((+)-norpseudoephedrine) (Fig. 2), are usually present at around 0.3–2.0%. Both substances are close chemical relatives of synthetic drugs such as amfetamine and methcathinone. Khat must be used fresh as the more active cathinone begins to deteriorate rapidly after harvesting. Since cathinone and cathine are closely related to synthetic drugs such as amfetamine, their mechanism of pharmacological activity is similar (see Amfetamine and Methamfetamine and MDMA above). Receptors for 5HT were shown to have an affinity to cathinone, suggesting that the chemical is responsible for feelings of euphoria associated with chewing khat.
Both cathine and cathinone are scheduled under the UN 1971 Convention, but khat itself is only specifically listed in a few jurisdictions. In the US, khat is controlled, but in the UK it is currently not because its use is relatively restricted, being more or less confined to a particular ethnic grouping for whom it has an important social function, rather in the way that tea and coffee do in other populations. Use has not graduated beyond that community to become an abuse problem.
Figure 1 (A) Bundles of khat as typically traded and (B) showing leaves, which are chewed.
Figure 2 (A) Cathinone; (B) cathine.
