Effects of a novel formulation of essential oils on glucose-insulin metabolism in diabetic and hypertensive rats: a pilot study.
BACKGROUND
Insulin resistance and its most severe form type 2 diabetes mellitus are rapidly increasing throughout the world. It is generally recognized that natural products with a long history of safety can increase insulin sensitivity.


OBJECTIVE
The present investigation examined the ability of various combinations of essential oils such as fenugreek, cinnamon, cumin, oregano, etc. to enhance insulin sensitivity. As a first approximation, we examined the effects of these natural products on Zucker fatty rats (ZFRs), a model of obesity and insulin resistance, and spontaneously hypertensive rats (SHRs), a model of genetic hypertension.


METHODS
Water or essential oils were given orally via droplets, and insulin sensitivity was estimated by systolic blood pressure (SBP) changes and circulating glucose and/or insulin concentrations.


RESULTS
We have found that the ability to alter SBP in rat models is the most sensitive early index of insulin sensitivity. The combined essential oils lowered circulating glucose levels and SBP in both ZFRs and SHRs, suggesting that these natural products are enhancing insulin sensitivity. The second series of studies examined two additional combinations of essential oils along with the original formula. The major differences were in the types and proportions of individual oils contributing to a given formula.


CONCLUSIONS
Although all the three formulae decreased SBP in ZFRs, one of the formulae was more effective than the others in lowering circulating glucose in the glucose tolerance testing. Accordingly, some essential oils may be added to the long list of natural products that can affect insulin sensitivity.
Talpur
N
N
Department of Physiology and Biophysics, Georgetown University Medical Center, Washington, DC 20057, USA.
Echard
B
B
Ingram
C
C
Bagchi
D
D
Preuss
H
H
D000284:Administration, Oral; D000818:Animals; D019440:Anti-Obesity Agents / Q000008:administration & dosage*; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test / Q000379:methods; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D009765:Obesity / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D009822:Oils, Volatile / Q000008:administration & dosage*; D051381:Rats; D011918:Rats, Inbred SHR; D011924:Rats, Zucker
D019440:Anti-Obesity Agents; D000959:Antihypertensive Agents; D001786:Blood Glucose; D007328:Insulin; D009822:Oils, Volatile; D005947:Glucose