title: Red pitaya juice supplementation ameliorates energy balance homeostasis by modulating obesity-related genes in high-carbohydrate, high-fat diet-induced metabolic syndrome rats.
abstract: BACKGROUND
  Red pitaya (Hylocereus polyrhizus) or known as buah naga merah in Malay belongs to the cactus family, Cactaceae. Red pitaya has been shown to give protection against liver damage and may reduce the stiffness of the heart. Besides, the beneficial effects of red pitaya against obesity have been reported; however, the mechanism of this protection is not clear. Therefore, in the present study, we have investigated the red pitaya-targeted genes in obesity using high-carbohydrate, high-fat diet-induced metabolic syndrome rat model.
  
  
  METHODS
  A total of four groups were tested: corn-starch (CS), corn-starch + red pitaya juice (CRP), high-carbohydrate, high-fat (HCHF) and high-carbohydrate, high-fat + red pitaya juice (HRP). The intervention with 5 % red pitaya juice was continued for 8 weeks after 8 weeks initiation of the diet. Retroperitoneal, epididymal and omental fat pads were collected and weighed. Plasma concentration of IL-6 and TNF-α were measured using commercial kits. Gene expression analysis was conducted using RNA extracted from liver samples. A total of eighty-four genes related to obesity were analyzed using PCR array.
  
  
  RESULTS
  The rats fed HCHF-diet for 16 weeks increased body weight, developed excess abdominal fat deposition and down-regulated the expression level of IL-1α, IL-1r1, and Cntfr as compared to the control group. Supplementation of red pitaya juice for 8 weeks increased omental and epididymal fat but no change in retroperitoneal fat was observed. Red pitaya juice reversed the changes in energy balance homeostasis in liver tissues by regulation of the expression levels of Pomc and Insr. The increased protein expression levels of IL-6 and TNF-α in HCHF group and red pitaya treated rats confirmed the results of gene expression.
  
  
  CONCLUSIONS
  Collectively, this study revealed the usefulness of this diet-induced rat model and the beneficial effects of red pitaya on energy balance homeostasis by modulating the anorectic, orexigenic and energy expenditure related genes.
authors.affiliation: Department of Food Science, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia. shazini@upm.edu.my.
authors.forename: Nurul Shazini
authors.initials: NS
authors.lastname: Ramli
authors.affiliation: Department of Biomedical Science, Universiti Putra Malaysia, Serdang, 43400, Malaysia.
authors.forename: Patimah
authors.initials: P
authors.lastname: Ismail
authors.affiliation: Department of Nutrition and Dietetics, Universiti Putra Malaysia, Serdang, 43400, Malaysia.
authors.forename: Asmah
authors.initials: A
authors.lastname: Rahmat
mesh_terms: D050153:Abdominal Fat / Q000187:drug effects; D000818:Animals; D029421:Cactaceae / Q000737:chemistry*; D059305:Diet, High-Fat; D000067030:Fruit and Vegetable Juices; D005786:Gene Expression Regulation / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects*; D024821:Metabolic Syndrome / Q000235:genetics* / Q000378:metabolism; D009765:Obesity / Q000235:genetics* / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats
chemical_list: D010936:Plant Extracts
keywords: Metabolic syndrome; Obesity-related genes; Red pitaya juice