Essential oils... How essential are they?

On Wednesday, November 19, I attended a chemistry/biochemistry seminar lead by Mohammed Kahn, Grad Student at UNCG, under the supervision of Dr. Gregory Raner. Mr. Kahn presented his thesis work involving the inhibition of Cytochrome P450 2E1 and Cytochrome P450 2A6 using essential oils, basil and tarragon. I know, I know... I was thinking the exact same thing you probably are, and even though the title is super intimidating the seminar was packed with very engaging, well presented information and was very educational as a whole.

Cytochrome P450 with Heme Cofactor (black center)

Background:

Pictured above is Cytochrome P450, a hemoprotein with involvement in a variety of enzymatic activities. Cytochrome P450 proteins have been found in all domains of life, but the concentration of this study is focused on humans, rabbits and rats. Cytochrome P450's mechanism of action begins as a substrate binds to the active site of the enzyme. Generally the substrate binds on the opposite side of the peptide chain, but still within relative proximity to the heme group. Binding of the substrate produces a conformation of the active site, which in turn can cause a change in the state of the heme iron and effect the overall activity of the enzyme and produce oxidative stress.

Study:

During his research Mr. Kahn hypothesized that essential oils, tarragon and basil, would exemplify inhibitory effects on Cytochrome P450 2E1 and Cytochrome P450 2A6, two proteins commonly found in the liver of humans, rabbits and rats that aid in the metabolism of drugs and steroids. Mr. Kahn developed an in vitro assay to determine protein activity levels and performed a series of experiments to test the inhibitory presence of both oils in all three subjects. He determined that the key determinant in the inhibition process was the compound phenylpropene, also known as Estragole. 

Estragole

Estragole (1-allyl-4-methoxybenzene) is a natural organic compound and component of many plants including tarragon and basil. The study results indicated that both essential oils, basil and tarragon, produced inhibitory effects of Cytochrome P450 2E1 and 2A6 protein activity. Tarragon induced greater inhibitory effects because of the high concentration of Estragole versus basil which contains lower concentrations of Estragole. To reduce the risk of error and further test his results, Mr. Kahn performed reversibility and supersome studies, both of which yielded the same results. In conclusion, increased concentrations of essential oils, tarragon and basil, produce increased inhibition of Cytochrome P450 proteins, therefore decreasing their enzymatic activity.

Hmmm... Essential oils may be one of the latest trends, but are they really that wonderful after all? Just some food for thought!

References/Photos:
http://en.wikipedia.org/wiki/Cytochrome_P450
http://www.rcsb.org/pdb/101/motm.do?momID=82
http://toxnet.nlm.nih.gov/cpdb/chempages/ESTRAGOLE.html
http://en.wikipedia.org/wiki/Estragole