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

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Hi All,

Seems a 150 ml cup of tea, made with a 2 g black or green tea bag, will give you

about 1,250 ORAC anti-oxidant units.

From other references I have found, herbal teas are generally ORAC low.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve & db=PubMed & list_uids=1\

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.

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. [1,250 per 150 ml..gw]

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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Good health & long life,

Greg ,

http://optimalhealth.cia.com.au