Histomorphological and metabolic effects of caralluma fimbriata in female rats

Caralluma fimbriata (Apocynaceae) is mainly used as a nutritional supplement to reduce body weight (Dutt et al., J Med Food 2012; 15:108-19) due to the presence of pregnane glycosides, also contained in other plants, all used as "natural" slimming essences. Nevertheless, there is only few scientific evidence on the efficacy and safety of C. fimbriata (Odendaal et al., Int J Toxicol. 2013; 32: 385-94; Vitalone et al., Eur J Clin Pharmacol 2011; 7: 215–224). Our aim was to analyse the effects of the long-term use of a standardized extract of C. fimbriata (Slimaluma®). 18 normal weight female Sprague Dawley rats were randomly assigned to a control and a C. fimbriata treated groups by administration of C. fimbriata (Slimaluma®) standardized extract (100 mg/kg/die) for a long-term treatment (58 days). Animal body weight and food and water consumption were recorded thrice a week. Blood, liver, gut and brain (hypothalamus and cerebral cortex) samples were collected. Metabolomic analysis, clinical-biochemical tests, histomorphology (LM), ultrastructure (TEM) and immunohistochemistry (NPY expression, polyclonal rabbit IgG antibody, Sigma, USA) were analysed. These data showed no significant effect on body weight, blood and metabolic parameters both in control and treated rats. There were no ultrastructural changes neither in the liver nor in the gut. There was a significant increase in food and water consumption in treated rats, without any body weight increase. There was an increase of NPY in the cerebral cortex and hypothalamic arcuate nucleus. C. fimbriata administration seems related to a modified distribution of central nervous system NPY, as an orexigenic neuromediator.