title: Effects of phenolic-rich extracts of Clinacanthus nutans on high fat and high cholesterol diet-induced insulin resistance.
abstract: BACKGROUND
  Clinacanthus nutans is used traditionally in many parts of Asia to improve well-being, but there are limited studies on its efficacy. We explored the potential use of C. nutans for prevention of high fat and high cholesterol diet-(HFHC-) induced insulin resistance in rats.
  
  
  METHODS
  The leaf of C. nutans was extracted using water (AL extract) and methanol (AML extract), and the extracts were fed to rats alongside the HFHC diet for 7 weeks, and compared with simvastatin. Oral glucose tolerance test, and serum insulin, retinol binding protein 4 (RBP4), adiponectin and leptin were measured. Homeostatic model assessment of insulin resistance (HOMA-IR) was computed, while transcriptional regulation of hepatic insulin signaling genes was also assessed.
  
  
  RESULTS
  Glycemic response was higher in the HFHC group compared with the AL and AML groups, which also had lower serum RBP4, fasting glucose, insulin and HOMA-IR. Serum adiponectin levels were higher, while leptin levels were lower in the AML and AL groups compared to the HFHC group. There was upregulation of the Insulin receptor substrate, phosphotidyl inositol-3-phosphate, adiponectin receptor and leptin recetor genes, in comparison with the HFHC group.
  
  
  CONCLUSIONS
  Overall, the results showed that the HFHC diet worsened metabolic indices and induced insulin resistance partly through transcriptional regulation of the insulin signaling genes. C.nutans, on the other hand, attenuated the metabolic effects and transcriptional changes induced by the HFHC diet. The results suggested that C.nutans may be a good source of functional ingredient for the prevention of insulin resistance.
authors.affiliation: Institute of Bioscience, Laboratory of Molecular Biomedicine, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.|Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: Nadarajan
authors.initials: N
authors.lastname: Sarega
authors.affiliation: Institute of Bioscience, Laboratory of Molecular Biomedicine, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia. mustyimam@gmail.com.
authors.forename: Mustapha Umar
authors.initials: MU
authors.lastname: Imam
authors.affiliation: Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: Norhaizan Md
authors.initials: NM
authors.lastname: Esa
authors.affiliation: Department of Food Science, Faculty of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia.
authors.forename: Norhasnida
authors.initials: N
authors.lastname: Zawawi
authors.affiliation: Institute of Bioscience, Laboratory of Molecular Biomedicine, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia. maznahis@upm.edu.my.|Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia. maznahis@upm.edu.my.
authors.forename: Maznah
authors.initials: M
authors.lastname: Ismail
mesh_terms: D027901:Acanthaceae / Q000737:chemistry*; D052242:Adiponectin / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000009:adverse effects; D059305:Diet, High-Fat; D004041:Dietary Fats / Q000009:adverse effects*; D007328:Insulin / Q000097:blood*; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics / Q000378:metabolism; D007333:Insulin Resistance / Q000235:genetics; D020738:Leptin / Q000097:blood; D010636:Phenols / Q000494:pharmacology*; D018129:Phosphatidylinositol Phosphates / Q000235:genetics / Q000378:metabolism; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D017207:Rats, Sprague-Dawley; D054417:Receptors, Adipokine / Q000235:genetics / Q000378:metabolism; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D002791:Cholesterol, Dietary; D004041:Dietary Fats; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D020738:Leptin; D010636:Phenols; D018129:Phosphatidylinositol Phosphates; D010936:Plant Extracts; C532035:Rbp4 protein, rat; D054417:Receptors, Adipokine; D054839:Retinol-Binding Proteins, Plasma