Friday, January 29, 2010

Piperine enhances the bioavailability of EGCG in mice

Epigallocatechin gallate (better known as EGCG) is a polyphenolic antioxidant plant metabolite found in green tea. It the most important catechin of green tea and has multiple health benefits. As useful as EGCG is it's bioavalability is weak. Bioavailability measures the absorption of nutrients in the human body. In mice the bioavailability of epigallocatechin gallate is 26,5% and in rats 1,6. For now it is unknown how well the catechins of green tea are absorbed in the human GI-tract, but in the light of these figures it looks like an interesting subject for a study.

Piperine and EGCG

Lambert & co have studied this exact problem. They conclude in their study that piperine (the alkaloid responsible for the taste of black pepper) enhances the bioavailability of EGCG in mice.

Piperine has the ability to prevent the glucuronidation (a process in body that makes substances more water-soluble). Glucuronidated substances are more easily excreted in urine. When glucuronidation is prevented the bioavailability of some substances is enhanced.

The microsomes in small intestine and liver effectively transform epigallocatechin gallate to a more water-soluble form. When the mice were given piperine along with EGCG the glucuronidation in the small intestine was reduced by 40 to 60 percent depending on dosage. The more piperine, the greater the preventitive effect.

EGCG - Chart 1

The chart represents that even with great piperin dosage there was no significant reduction in the hepatic glucuronidation. Small intestinal glucuronidation on the other hand was significantly reduced.

When mice were given epigallocatechin gallate and piperine the level of EGCG in blood plasma increased significately.
EGCG - Chart 2

The chart displays the plasma epigallocatechin gallate level  with and without piperine.

Piperine reduces the excretion of epigallocatechin gallate. When mice were given piperin the amount of EGCG in stool was reduced which is a good sign of enhanced bioavailability.

EGCG - Chart 3

As shown in the chart the effect of piperine is clear. Compared to the control group less than half of epigallocatechin gallate hadexcreted in stool in the piperin group after five hours.

At the moment it is not clear what effect piperin has in humans. In the test piperine dosage was 40 percent of the EGCG dosage. One cup of green tea has in average 180mg of ECGC (depends on the quality of the tea and the infusion time). Black pepper contains about 5-10% piperine. So you should ingest about 1,5 grams of black pepper per cup of green tea to get a similar relation as used in the test.

1 comment:

  1. That's pretty much just what I was looking for. I typed ecgc piperine into google, and right before I could click scholar this came up. Thumbs up.