Green Tea (Camellia sinensis) 19124972
Blood and Urine Levels of Tea Catechins after Ingestion of Different Amounts of Green Tea by Human Volunteers CSV JSON

The inhibitory activity of tea against tumorigenesis has been demonstrated in many animal models and has been suggested by some epidemiological studies. Such activity has generally been attributed to tea catechins. To understand the bioavailability of tea catechins in humans, we gave 18 individuals different amounts of green tea and measured the time-dependent plasma concentrations and urinary excretion of tea catechins. After taking 1.5, 3.0, and 4.5 g of decaffeinated green tea solids (dissolved in 500 ml of water), the maximum plasma concentration (Cmax) of (-)-epigallocatechin-3-gallate (EGCG) was 326 ng/ml, the Cmax of (-)-epigallocatechin (EGC) was 550 ng/ml, and the Cmax of (-)-epicatechin (EC) was 190 ng/ml. These Cmax values were observed at 1.4-2.4 h after ingestion of the tea preparation. When the dosage was increased from 1.5 to 3.0 g, the Cmax values increased 2.7-3.4-fold, but increasing the dose to 4.5 g did not increase the Cmax values significantly, which suggested a saturation phenomenon. The half-life of EGCG (5.0-5.5 h) seemed to be higher than the half-life of EGC or EC (2.5-3.4 h). EGC and EC, but not EGCG, were excreted in the urine. Over 90% of the total urinary EGC and EC was excreted within 8 h. When the tea dosage was increased, the amount of EGC and EC excretion seemed to increase, but a clear dose-response relationship was not observed. The present study provides basic pharmacokinetic parameters of green tea catechins in humans; these parameters may be used to estimate the levels of these compounds after drinking tea.

PMID: 9568793

9568793

1 . Blood and urine levels of tea catechins after 4.5 g green tea extract administration (id=NPDI-kZAc2A)

In Vivo Pharmacokinetics Study

Results

Sample Compound measured Value Measurement Study sequence Additional information N replicates

Experimental Conditions

Single dosing

Population

Healthy volunteers

6

The subjects refrained from drinking tea for 2 days before the experiment.

Pharmacokinetic (PK) Sampling Information

blood samples: 0, 0.5, 2, 4, 8, and 24 h; urine samples: before the dose and during periods of 0-2, 2-6, 6-8, 8-24, and 24-48 h after the dose

Drug or Natural Product Administration

Natural Product Administration

Oral

Beverage preparation was formulated by combining decaffeinated green tea extract solid 4.5 g with 45 g of sucrose, 7.5 g of coffee whitener (Borden 1-22007), and vanilla flavor (Tastmaker Lot SOS 5019). These beverage preparations were reconstituted in 500 mL of hot water.

4.5 g decaffeinated green tea extract

Fasted

Decaffeinated green tea extract was administered after an overnight fast

Single dose

Natural Product Characteristics

not available

2 . Blood and urine levels of tea catechins after 3.0 g green tea extract administration (id=NPDI-F2VDuA)

In Vivo Pharmacokinetics Study

Results

Sample Compound measured Value Measurement Study sequence Additional information N replicates

Experimental Conditions

Single dosing

Population

Healthy volunteers

6

Pharmacokinetic (PK) Sampling Information

blood samples: 0, 0.5, 2, 4, 8, and 24 h; urine samples: before the dose and during periods of 0-2, 2-6, 6-8, 8-24, and 24-48 h after the dose

Drug or Natural Product Administration

Natural Product Administration

Oral

Beverage preparation was formulated by combining decaffeinated green tea extract solid 3.0 g with 45 g of sucrose, 7.5 g of coffee whitener (Borden 1-22007), and vanilla flavor (Tastmaker Lot SOS 5019). These beverage preparations were reconstituted in 500 mL of hot water.

3.0 g decaffeinated green tea extract

Fasted

Decaffeinated green tea extract was administered after an overnight fast

Single dose

Natural Product Characteristics

not available

3 . Blood and urine levels of tea catechins after 1.5 g green tea extract administration (id=NPDI-ZpUpLQ)

In Vivo Pharmacokinetics Study

Results

Sample Compound measured Value Measurement Study sequence Additional information N replicates

Experimental Conditions

Single dosing

Population

Healthy volunteers

6

The subjects refrained from drinking tea for 2 days before the experiment.

Pharmacokinetic (PK) Sampling Information

blood samples: 0, 0.5, 2, 4, 8, and 24 h; urine samples: before the dose and during periods of 0-2, 2-6, 6-8, 8-24, and 24-48 h after the dose

Drug or Natural Product Administration

Natural Product Administration

Oral

Beverage preparation was formulated by combining decaffeinated green tea extract solid 1.5 g with 45 g of sucrose, 7.5 g of coffee whitener (Borden 1-22007), and vanilla flavor (Tastmaker Lot SOS 5019). These beverage preparations were reconstituted in 500 mL of hot water.

1.5 g decaffeinated green tea extract

Fasted

Decaffeinated green tea extract was administered after an overnight fast

Single dose

Natural Product Characteristics

not available