Isolation and characterization of hypoglycaemic principles of Bixa orellana

Preliminary studies have shown that a crude annatto seed extract, exhibited both hypo- and hyper- glycaemia. This present investigation sought to isolate the hypoglycaemic principle(s) and to determine its activity in both normal and streptozotocin diabetic dogs. The hypoglycaemic extract was isolated by a series of solvent/solvent extractions and by column chromatography. Glucose tolerance tests, radioimmunoassay of insulin, glucagon and C-peptide as well as receptor studies on mononuclear leucocytes and erythrocytes were performed. Consistent hypoglycaemia, increased insulin levels, decreased glucagon levels as well as delayed glucose absorption were shown. Increased insulin levels was not due to increased insulin synthesis. Increased binding of insulin to both white and red cells was shown while increased receptor affinity was demonstrated in the red cells. There is some indication that this extract has some similarities to sulphonylureas in terms of mode of action. (AU)

Extraction of an hyperglycaemic principle from the annatto (Bixa orellana)

The red powdery extract from the seeds of the annatto, Bixa orellana, is a well known food colouring. In an oil suspension it is used as a folk remedy (bush tea) in the West Indies, for diabetes mellitus. Detailed investigations on this extract, yielded a methyl ester, trans-bixin, molecular weight 394 and molecular formula C24 H30 O4. This purified substance was demonstrated, in anaaesthetised mongrel dogs, to cause hyperglycaemia. Concomitant electron microscopy of tissues biopsies, revealed damage to mitochrondria and endoplasmic reticulum mainly in liver and pancreas. When dogs were fed on a diet fortified with riboflavin, there was neither demonstratable tissue damage nor associated hyperglycaemia. These findings point to: (i) the potential dangers of informal medications such as 'bush teas'; (ii) the possible role of plant extracts/food additives in the development of diabetes mellitus especially in the undernourished state. (AU)