Six percent of the world’s population is believed to have diabetes. It causes blood sugar abnormalities and lipid abnormalities characterized by increased triglycerides, high *LDL-cholesterol, low **HDL-cholesterol, and oxidative stress, resulting in inflammation. Lipid abnormalities play a role in arteriosclerosis.

***Annatto (Bixa orellana) is a plant containing carotenoids bixin (BIX) and norbixin (NBIX). Annatto has been primarily used for food coloring and is known to be antioxidant. BIX is lipid soluble, while NBIX is water soluble. BIX is more concentrated in the plant. Oily extracts of annatto lower blood sugars in dogs, while alcohol extracts raise their blood sugars.

The purpose of the present study is to determine the effects of BIX and NBIX on blood sugar levels, lipid levels and oxidative stress in rats with diabetes induced by streptozotocin (STZ). Eight groups of rats were tested as follows: Non-diabetic controls, diabetic controls, diabetics treated with 10 mg/kg BIX, diabetics treated with 100 mg/kg BIX, diabetics treated with 10 mg/kg NBIX, diabetics treated with 100 mg/kg NBIX, diabetics treated with metformin, and diabetics treated with insulin. Blood from all animals was tested for glucose, LDL-cholesterol, HDL-cholesterol, triglycerides, antioxidant enzymes, products of protein oxidation, glutathione peroxidase, and glutathione reductase.

The results of the study are that STZ causes diabetes which increased bloods sugars four times. BIX treatment at high and low doses show a reduction in blood glucose levels similar to the reduction caused by metformin pharmaceutical for diabetes, but not as much as produced by insulin treatment. Rats treated with NBIX do not have improved blood sugars. Metformin reduced total cholesterol, while NBIX 100 mg/kg increased total cholesterol levels. Treatment with BIX 100 mg/kg or metformin reduces LDL-cholesterol, while NBIX 100 mg/kg increases LDL-cholesterol levels. Treatment with insulin or NBIX 10 mg/kg decreases HDL-cholesterol levels, while BIX 100 mg/kg increases HDL-cholesterol levels.

BIX 100 mg/kg treatment reduces the markers of protein oxidation. NBIX at the same dose increases the markers of protein oxidation.

CONCLUSION: STZ-induced diabetes in rats treated with BIX from annatto can be treated with BIX. The rats show less hyperglycemia. BIX has a positive effect on blood lipids, while NBIX has a negative effect. BIX shows antioxidant activity and reduced oxidative stress, while NBIX increases oxidative stress. BIX is a promising treatment for diabetes in humans.

NOTE: *A reduction in LDL-cholesterol levels is desired. **An increase in HDL-cholesterol is desired.

***Annatto is a small tree, sometimes known as achiote. Annato powder was used to color margarine in the mid-1900’s to make it look like butter.

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PMID: 24644139.

Summary #641.