METHODS: GBR were extracted separately by employing different solvents with ultrasound-assisted. Pancreatic lipase activity was determined spectrophotometrically by measuring the hydrolysis of p-nitrophenyl butyrate (p-NPB) to p-nitrophenol at 405 nm. Adipogenesis and lipolysis were assayed in fully differentiated 3T3-L1 adipocytes by using Oil Red O staining and glycerol release measurement.

AIMS: The objectives of this study were to determine the effects of khat and its active alkaloid, cathinone, on food intake and body weight in mice maintained on a high-fat diet, and to investigate its mechanism of action in white adipose tissue and in the hypothalamus.

MATERIALS & METHOD: Adult male mice (C57BL/6J) were fed a high fat diet (HFD) for 8 weeks (n = 30), then divided into 5 groups and treated daily for a further 8 weeks with HFD + vehicle [control (HFD)], HFD + 15 mg/kg orlistat (HFDO), HFD + 200 mg/kg khat extract (HFDK200), HFD + 400 mg/kg khat extract (HFDK400) and HFD + 3.2 mg/kg cathinone (HFDCAT). Treatments were carried out once daily by gastric gavage. Blood and tissue samples were collected for biochemical, hormonal and gene expression analyses.

Methods: Mice (n = 48) were fed high-fat diet (HFD) for 25 weeks to induce obesity, after which half were maintained on HFD and half switched to low-fat diet (LFD)while they were given normal water (H2O) or 0.1% (w/v) SCE in water at week 0-4 which was increased to 1% (w/v) at week 5-9. Effects of treatment with SCE were compared between HFDH2O, HFDSCE, LFDH2O and LFDSCE groups. Respiratory exchange ratios (RER) were measured at weeks 0, 5 and 10. Food, water intake and body weight were measured weekly. Plasma lipid profile and organ weights were determined at week 10.

Results: SCE had significantly reduced RER at week 9 (P = 0.011). Food intake, body weight, and abdominal adipose tissue weight were not altered by SCE at weeks 5 and 10. However, significant increase in plasma and liver cholesterol (P < 0.050) was observed.