The effect of Khat (Catha edulis) as an appetite suppressant is independent of ghrelin and PYY secretion.
BACKGROUND
The leaves of the khat plant (Catha edulis) are chewed for their pleasurable effects. Chewing releases cathinone which may decrease appetite through an unknown mechanism. Levels of the peptide ghrelin increase with hunger and decrease immediately post-prandially, while peptide YY is released following a meal. We hypothesised that the anorexigenic effects of khat may be mediated through changes in these hormones.


METHODS
Six habitual khat chewers attended on two separate occasions. For a period of 3h they chewed either khat leaves or lettuce. Blood pressure (BP) and pulse rate (PR) were monitored throughout, as were subjective assessments of hunger and fullness. Plasma samples were analysed for cathinone, ghrelin and PYY levels.


RESULTS
Chewing khat significantly decreased subjective feelings of hunger and increased fullness (p<0.05) but had no effect on ghrelin and PYY levels. Khat led to an increase in cathinone levels as well as an increase in BP and PR. Cathinone levels correlated positively with fullness and pulse rate and negatively with hunger.


CONCLUSIONS
Chewing khat decreases subjective feelings of hunger and increases systemic sympathetic tone, but has no effect on ghrelin and PYY levels. We conclude that the anorexigenic effect of khat may be secondary to central mechanisms mediated via cathinone.
Murray
Charles D R
CD
Royal Free Hospital, London, United Kingdom. charles.murray@royalfree.nhs.uk
Le Roux
Carel W
CW
Emmanuel
Anton V
AV
Halket
John M
JM
Przyborowska
Anna M
AM
Kamm
Michael A
MA
Murray-Lyon
Iain M
IM
D000328:Adult; D000470:Alkaloids / Q000097:blood; D001066:Appetite / Q000187:drug effects* / Q000502:physiology; D001067:Appetite Depressants / Q000494:pharmacology*; D019540:Area Under Curve; D001794:Blood Pressure / Q000187:drug effects; D029754:Catha / Q000737:chemistry*; D018592:Cross-Over Studies; D054439:Ghrelin / Q000378:metabolism*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008409:Mastication / Q000502:physiology; D008875:Middle Aged; D019894:Peptide YY / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D019518:Postprandial Period
D000470:Alkaloids; D001067:Appetite Depressants; D054439:Ghrelin; D010936:Plant Extracts; D019894:Peptide YY; C023665:cathinone