Rosemary extract enriched in carnosic acid shows anti-obesity and anti-diabetic effects on in vitro and in vivo models

Rosemary (Rosmarinus officinalis L.) leaf extract standardized to 20% carnosic acid (RE) has shown good antioxidant properties in both ORAC in vitro and LDL oxidation ex vivo assays [1]. Regulating fat absorption by inhibiting the action of the pancreatic lipase activity is an effective way to reduce body weight and obesity [2]. PPARγ represents the major target for the glitazone type of drugs used for the treatment of type 2 diabetes [3]. Therefore, we evaluated the in vitro capacities of RE to inhibit pancreatic lipase activity compared to tetrahydrolipstatin, and to activate PPARγ in a cell based assay compared to rosiglitazone. In addition, we studied the effects of a low-fat diet (LFD), high-fat diet (HFD), and high-fat diet at 500 mpk RE (RED) on C57BL/6J mice during 16 weeks. In vitro results showed that RE was able to inhibit pancreatic lipase activity by 69.8% at 100µg/ml (P<0.001) and activate PPARγ by 23% at 50µg/ml (P<0.05) as compared to their respective positive controls. In the in vivo experiment, after a 16 week treatment and compared to both control groups, we observed that RED reduced by 67.7% the body weight gain (P<0.001) and by 79.4% the adipose tissue gain (P<0.001), without affecting the food intake. RED lowered total cholesterol increase by 68.4 (P<0.01). Glycemia was reduced by 72.0% (P<0.05). RED did not show any modification in the safety parameters measured as liver weight gain, AST and ALT levels. These results encourage conducting further studies on obesity and diabetes control using RE.

References: 1. Ibarra, A. et al. (2010)J Med Food In press.

2. Kim, HY and Kang, MH. (2005). Phytother Res 19:359–361.

3. Evans, RM. et al (2004). Nat Med 10:355–361.