Catalpic acid decreases abdominal fat deposition, improves glucose homeostasis and upregulates PPAR alpha expression in adipose tissue.
OBJECTIVE
Catalpic acid (CAT) is a conjugated linolenic acid (CLN) isomer containing trans-9, trans-11, cis-13 double bonds in an 18-carbon chain and it is found primarily in the seed oil of ornamental and medicinal trees and shrubs of the family Bignoniaceae. The objective of this study was to investigate whether CAT decreases obesity and ameliorates insulin sensitivity and glucose tolerance in mice fed high-fat diets.


METHODS
To test the efficacy of CAT in decreasing obesity and diabetes we used both a model of diet-induced obesity (DIO) and a genetic model of obesity (i.e., mice lacking the leptin receptor). Blood was collected on days 0, 7, 14, 21 and 28 for determining fasting glucose and insulin concentrations in plasma. In addition, a glucose tolerance test was administered on day 28.


RESULTS
We found that dietary CAT (1g/100g) decreased fasting plasma glucose and insulin concentrations, ameliorated the glucose normalizing ability following glucose challenge and decreased abdominal white adipose tissue accumulation. In white adipose tissue (WAT), CAT upregulated peroxisome proliferator-activated receptor (PPAR) alpha and its responsive genes [i.e., stearoyl-coenzyme A desaturase (SCD1) and enoyl-coenzyme A hydratase (ECH)], increased concentrations of high-density lipoprotein (HDL) cholesterol and decreased plasma triglyceride (TG) levels.


CONCLUSIONS
CAT decreased abdominal fat deposition, increased HDL cholesterol, decreased TG concentrations, decreased glucose and insulin homeostasis and modulated WAT gene expression in a manner reminiscent of the actions of the PPAR alpha-activating fibrate class of lipid-lowering drugs.
Hontecillas
Raquel
R
Laboratory of Nutritional Immunology and Molecular Nutrition, Virginia Bioinformatics Institute, Virginia Tech, VA, USA.
Diguardo
Maggie
M
Duran
Elisa
E
Orpi
Marcel
M
Bassaganya-Riera
Josep
J
D050153:Abdominal Fat / Q000187:drug effects*; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D029402:Bignoniaceae / Q000737:chemistry; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage; D005786:Gene Expression Regulation / Q000187:drug effects*; D006706:Homeostasis / Q000187:drug effects; D007328:Insulin / Q000097:blood; D044243:Linoleic Acids, Conjugated / Q000008:administration & dosage*; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000188:drug therapy / Q000517:prevention & control; D047493:PPAR alpha / Q000235:genetics*; D012639:Seeds / Q000737:chemistry; D015854:Up-Regulation
D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin; D044243:Linoleic Acids, Conjugated; D047493:PPAR alpha; C534730:catalpic acid