Extraction of an hyperglycaemic principle from the annatto (Bixa orellana), a medicinal plant in the West Indies.

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 C24H30O4. This purified substance was demonstrated, in anaesthetised mongrel dogs, to cause hyperglycaemia. Concomitant electron microscopy of tissue biopsies, revealed damage to mitochondria and endoplasmic reticulum mainly in liver and pancreas. When dogs were fed on a diet fortified with riboflavin, there was neither demonstrable 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.