Hypoglycaemic activity of Bixa orellana extract in the dog

Methods Find Exp Clin Pharmacol. 2008 May;30(4):301-5. doi: 10.1358/mf.2008.30.4.1186073.


In West Indian folklore, a variety of plants are used for medicinal purposes. One such plant, Bixa orellana (annatto), is commonly used in the treatment of diabetes mellitus. Preliminary studies have shown that a crude annatto seed extract exhibited either glucose lowering or hyperglycaemia-inducing activity depending on how it was further manipulated. This present investigation sought to determine the effects of the glucose-lowering extract on C-peptide and streptozotocin-induced diabetic dogs. This annatto extract was found to decrease blood glucose levels in fasting normoglycaemic and streptozotocin-induced diabetic dogs. In addition, in normal dogs, it suppressed the postprandial rise in blood glucose after an oral glucose load. Interestingly, the extract also caused an increase in insulin-to-glucose ratio in normal dogs. Increased insulin levels were not due to increased insulin synthesis as after 1-h residence time and half-hour postprandial, decreased C-peptide levels was observed. It was concluded that Bixa orellana (annatto) lowered blood glucose by stimulating peripheral utilization of glucose, and it is possible that this glucose-lowering extract might be of pharmacological importance.

MeSH terms

  • Animals
  • Bixaceae / chemistry*
  • Blood Glucose / drug effects
  • C-Peptide / drug effects
  • C-Peptide / metabolism
  • Carotenoids / isolation & purification
  • Carotenoids / pharmacology*
  • Diabetes Mellitus, Experimental / drug therapy*
  • Dogs
  • Female
  • Hypoglycemic Agents / isolation & purification
  • Hypoglycemic Agents / pharmacology*
  • Insulin / blood
  • Male
  • Medicine, Traditional
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology*
  • Postprandial Period
  • Streptozocin
  • Time Factors
  • West Indies


  • Blood Glucose
  • C-Peptide
  • Hypoglycemic Agents
  • Insulin
  • Plant Extracts
  • Carotenoids
  • Streptozocin
  • annatto