Reducing effect of a combination of Phaseolus vulgaris and Cynara scolymus extracts on operant self-administration of a chocolate-flavoured beverage in rats

Treatment with a rational combination of standardized extracts of Phaseolus vulgaris and Cynara scolymus reduced food intake and glycemia in rats. The present study was designed to assess the effect of this extract combination and of each single extract in an experimental model of food craving, made up of rats displaying exaggerated seeking and taking behaviors for a chocolate-flavoured beverage. After training to lever-respond for the chocolate-flavoured beverage, rats were treated with vehicle, Phaseolus vulgaris extract alone (200 mg/kg), Cynara scolymus extract alone (400 mg/kg), or combination of Phaseolus vulgaris (200 mg/kg) and Cynara scolymus (400 mg/kg) extracts. The Phaseolus vulgaris extract and the extract combination exerted similar and substantial decrements in number of lever-responses and amount of self-administered chocolate-flavoured beverage; conversely, the Cynara scolymus extract was totally ineffective. These results suggest that (a) the capacity of the extract combination to reduce the self-administration of the chocolate-flavoured beverage entirely relied on the Phaseolus vulgaris extract, (b) Phaseolus vulgaris extract may interfere with the mechanisms regulating food-related addictive-like behaviors, and (c) combinations of Phaseolus vulgaris and Cynara scolymus extracts may possess a broad spectrum of activities, from treatment of metabolic syndrome to overweight, obesity, and possibly food-related addictive disorders.