Antioxidant capacity and polyphenolic components of teas: implications for altering in vivo antioxidant status.

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0202399 & dopt=Abstract

Proc Soc Exp Biol Med 1999 Apr;220(4):255-61 Related Articles, Books, LinkOut

Antioxidant capacity and polyphenolic components of teas: implications for

altering in vivo antioxidant status.

Prior RL, Cao G.

US Department of Agriculture, Agriculture Research Service, Mayer Human

Nutrition Research Center on Aging at Tufts

University, Boston, Massachusetts 02111, USA.prior@...

The Oxygen Radical Absorbance Capacity (ORAC) assay was used to determine the

total antioxidant capacity of tea. Green

and black teas (n = 18) had a mean antioxidant capacity of 761.1 +/- 85.3

micromol Trolox Equivalents (TE) per g dry

matter. However, their antioxidant capacity varied from 235 micromol to over

1526 micromol Trolox equivalents (TE)/g dry

matter, and total phenolics ranged from 32 to 147 mg/g in different commercial

teas.

One tea phenolics extract had an antioxidant capacity of 4796 micromol TE/g dry

matter and 625 mg total phenolics/g.

[Anyone know what tea achieved this massive rating??? Anyone have access to the

full text PDF??..gw]

On a dry matter basis, an antioxidant capacity of 761 micromol TE/g is

considerably higher than any of the other fruits

and vegetables measured in our laboratory. However, since dry tea is not

consumed directly, brewing conditions may

influence the final antioxidant capacity in the tea as consumed.

We tested both green and black teas by placing one tea bag (1.95 g) in 150 ml (5

oz.) of boiling water. In the first

brewed cup, approximately 84% of the total antioxidant activity was solubilized

within the first 5 min of brewing. An

additional 13% of the antioxidant activity was extracted into the second glass

of 150 ml with an additional 5 min of

brewing. At the dilutions obtained after the first brewing, the tea as consumed

would contain approximately 8. 31

micromol TE per ml. This total antioxidant capacity compares to other drinks

from fruits and vegetables that had

antioxidant capacity values ranging from 1.6 to 15 micromol TE/ml.

At these antioxidant levels, consumption of 150 ml of tea could make a

significant contribution to the total daily

antioxidant capacity intake. (-)-Epicatechin and (+)-catechin, two components

from tea, had an antioxidant capacity of

2.36 and 2.49 micromol/micromol or 8. 13 and 8.58 micromol/mg, respectively. In

16 tea samples we observed a mean of

10.0 +/- 0.6 micromol TE/mg total phenolics. Tea can be an important source of

what has been referred to as

" non-nutrient " antioxidant phytochemicals. However, with the variation that

exists in antioxidant capacity with various

tea preparations, measures of antioxidant capacity intake are critical to the

study of intake and health outcomes and/or

biomarkers of health outcomes.

PMID: 10202399 [PubMed - indexed for MEDLINE]

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Bottom line. You should get about 1,200 ORACs from brewing up a 2 g bag of tea

and maybe a lot more.

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Good health & long life,

Greg ,

http://optimalhealth.cia.com.au