LAUSR

ETHNOPHARMACOLOGICAL RELEVANCE Khat (Catha edulis (Vahl) Forssk.) is a herb from the Celastraceae family (also known as qat, gaad, or mirra) that is widely-consumed in East Africa and in the Arabian peninsula. The green leaves and small stems are consumed primarly at recreational and social gatherings, and medicinally for their antidiabetic and appetite-suppression effects. 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 + 15mg/kg orlistat (HFDO), HFD + 200mg/kg khat extract (HFDK200), HFD + 400mg/kg khat extract (HFDK400) and HFD + 3.2mg/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. RESULTS Khat extracts and orlistat treatment significantly reduced weight gain as compared to control mice on HFD, and cathinone administration completely prevented weight gain in mice fed on HFD. Khat treatment caused a marked reduction in body fat and in serum triglycerides. A dose-dependent effect of khat was observed in reducing serum leptin concentrations. Analysis of gene expression in adipose tissue revealed a significant upregulation of two lipolysis pathway genes:(adipose triglyceride lipase (PNPLA-2) and hormone-sensitive lipase (LIPE). In the hypothalamic there was a significant (P<0.05) upregulation of agouti-related peptide (AgRP) and cocaine-amphetamine regulated transcript (CART) genes in the HFDK400 and HFDCAT groups. CONCLUSION Cathinone treatment blocked body weight gain, while high dose khat extract significantly reduced the weight gain of mice on an obesogenic diet through stimulation of lipolysis in white adipose tissue.