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.

AIM OF THE STUDY: This study aims to investigate the anti-obesity and lipid lowering effects of ethanolic extract of C. cauliflora leaves and its major compound (vitexin) in C57BL/6 obese mice induced by high-fat diet (HFD), as well as to further identify the molecular mechanism underlying this action.

METHODS AND MATERIAL: Male C57BL/6 mice were fed with HFD (60% fat) for 16 weeks to become obese. The treatment started during the last 8 weeks of HFD feeding and the obese mice were treated with C. cauliflora leaf extract at 200 and 400 mg/kg/day, orlistat (10 mg/kg) and vitexin (10 mg/kg).

RESULTS: The oral administration of C. cauliflora (400 and 200 mg/kg) and vitexin significantly reduced body weight, adipose tissue and liver weight and lipid accumulation in the liver compared to control HFD group. Both doses of C. cauliflora also significantly (P ≤ 0.05) decreased serum triglyceride, LDL, lipase, IL-6, peptide YY, resistin levels, hyperglycemia, hyperinsulinemia, and hyperleptinemia compared to the control HFD group. Moreover, C. cauliflora significantly up-regulated the expression of adiponectin, Glut4, Mtor, IRS-1 and InsR genes, and significantly decreased the expression of Lepr in white adipose tissue. Furthermore, C. cauliflora significantly up-regulated the expression of hypothalamus Glut4, Mtor and NF-kB genes. GC-MS analysis of C. cauliflora leaves detected the presence of phytol, vitamin E and β-sitosterol. Besides, the phytochemical evaluation of C. cauliflora leaves showed the presence of flavonoid, saponin and phenolic compounds.

METHODS: Seventy-six obese subjects were randomly placed into two groups. The first group received three daily 120 mg dosages of orlistat for nine months (n=39), and the second group received a once daily 10 or 15 mg dosage of sibutramine for nine months (n=37). Baseline measurements for weight, body mass index (BMI), waist circumference (WC), body fat percentage (BF), visceral fat (VF), adiponectin, fasting plasma glucose (FPG), fasting insulin, pancreatic B cell secretory capacity (HOMA%B), insulin sensitivity (HOMA%S), insulin resistance (HOMA-IR) and serum high sensitivity C-reactive protein (hs-CRP) were performed and repeated during the sixth and ninth months of treatment.

RESULTS: Twenty-four subjects completed the trial in both groups. For both groups, weight, BMI, WC, BF, VF, HOMA-IR and hs-CRP were significantly lower at the end of the nine month intervention. However, there were no significant differences between the two groups for these parameters with nine months treatment. There was a significant decrease in FPG in orlistat group; while fasting insulin and HOMA%B reduced in sibutramine group. For both groups, there were also significant increases in adiponectin levels and HOMA%S at the end of the nine month intervention.