Roles of Rheum palmatum in the regulation of food intake and neuropeptides expression

Abstract

Hypothalamus is the center of regulating appetite and energy homeostasis. Neuropeptide Y (NPY) and Agouti related peptide (AgRP) are orexigenic neuropeptides, which are responsible for appetite stimulation. Pro-opiomelanocortin (POMC) and cocaine and amphetamine regulated transcript (CART) are anorexigenic neuropeptides. These neuropeptides are involved in satiety. Events of uncontrolled appetite can lead to metabolic diseases, such as anorexia and obesity. Despite the issues related to these metabolic diseases, effective treatment for neither anorexia nor obesity has been developed. Currently available treatments for anorexia and obesity can cause severe side effects. For this reason, natural compounds that can potentially regulate appetite were screened in this study. Natural compounds have vast chemical diversities and are an excellent source for developing new pharmaceuticals. Thus, the objective of this study is to discover natural compounds that can either stimulate or suppress appetite. Twenty natural compounds were selected from New Natural Material Bank. Out of twenty natural compounds, Rheum palmatum standized sample 1 (RPSS1) induced neuropeptide Y (NPY) expression. RPSS1 increased NPY expression by four folds in mHypoA-NPY/GFP cell line. However, food intake and body weight of the mice was reduced when RPSS1 was intracerebroventrically (icv) injected into the 3rd ventricle. In addition, there was no change in any of the neuropeptides mRNA expression in the hypothalamus. The in vivo results suggest that RPSS1 controls food intake by not regulating neuropeptides but by other mechanism in hypothalamus. ⓒ 2015 DGIST