Introduction. Khat (Catha edulis) is an evergreen tree/shrub that is thought to affect sexual motivation or libido. Its positive effect on sexual desire is more frequently observed in females than in males and occurs when khat is chewed. Thus, khat's effects on sexual behavior may depend on the release mode of its active constituent.
Aim. This study aimed to investigate the effect of dried khat alkaloids on the sexual motivation and estradiol levels of female rats, with special emphasis on the importance of the sustained release effect.
Methods. Dried khat leaves were extracted and isolated. The alkaloids in khat extract were identified and calculated using thin layer chromatography and high-performance liquid chromatography. The isolated khat extract was microencapsulated using a phase separation coacervation method. The morphology, particle size, yield, drug loading, and entrapment efficiency were evaluated. The in vitro release and stability of alkaloids in khat extract and in khat extract microcapsules were determined. The effect of khat extract microcapsules and varying doses of khat extract on sexual motivation in female rats were investigated. Additionally, estradiol levels, vaginal secretions and vaginal pH were determined.
Main Outcome Measures. The differences in the effect of khat extract and khat extract microcapsules on sexual motivation, vaginal secretion and estradiol levels in female rats were compared.
Results. Cathine and norephedrine were identified in the isolated khat extract at composition of 81.3% and 17.2%, respectively. Among the formulations studied, khat extract microcapsules of formulation 2:3:5 (containing a ratio of khat extract to ovalbumin to gelatin of 2:3:5) were found to exhibit higher yield, loading, and entrapment efficiency. Khat extract microcapsules showed sustained in vitro release and were more stable than khat extract. In addition, khat extract microcapsules enhanced sexual motivation, increased vaginal secretions, and upregulated estradiol level in female rats.
Conclusion. The sustained release of alkaloids from dried khat has significantly enhanced the sexual motivation and increased the estradiol level of female rats. Thus the release of dried khat alkaloids from microcapsules might be an effective means of enhancing the libido in females. Aziz HA, Peh KK, and Tan YTF. Extraction and microencapsulation of khat: Effects on sexual motivation and estradiol level in female rats. J Sex Med 2009;6:682–695.