Green Tea (Camellia sinensis) 19124972
Identification of Intestinal UDP-Glucuronosyltransferase Inhibitors in Green Tea (Camellia sinensis) Using a Biochemometric Approach: Application to Raloxifene as a Test Drug via In Vitro to In Vivo Extrapolation CSV JSON

Green tea is a commonly consumed beverage worldwide; thus, identifying green tea-drug interactions would be of high impact. The potential for UDP-glucuronosyltransferase (UGT)-based interactions are relatively understudied, particularly those in the intestine. As with all botanical dietary supplements, green tea is a complex and variable mixture of diverse phytoconstituents. Comprehensive, high-throughput, robust methods are needed to identify candidate precipitants of interactions with drugs. Using a biochemometrics approach that combines chemometrics with established bioassays, intestinal UGT inhibitors in green tea were identified and evaluated for their in vivo interaction potential. Four widely available green teas that were chemically similar to the National Institute of Standards and Technology (NIST) leaf reference material were selected for evaluation as inhibitors of intestinal UGT activity using human intestinal microsomes. Extracts and five fractions (prepared from the original extracts) of each tea were tested (20, 60, 180 µg/mL) using the nonspecific fluorescent substrate 4-methylumbelliferone. Fractions rich in UGT inhibitory constituents were identified via mass spectrometry-based untargeted metabolomics; these fractions were fractionated further and subjected to biochemometric analysis to identify individual UGT inhibitors. The Ki of two of these constituents and the original extract of a representative tea were determined using raloxifene a clinically relevant substrate. The Ki values were applied to a mechanistic static model to evaluate the potential for a green tea-raloxifene interaction in vivo. Effects of the extracts and fractions from all four teas were qualitatively similar, inhibiting intestinal UGT activity in a concentration-dependent manner (by 0 to >95% relative to vehicle control). The UGT inhibitory constituents tended to reside in the more hydrophilic subfractions of the fraction prepared from the representative extract. (−)-Epigallocatechin gallate (EGCG) and (−)-epicatechin gallate (ECG), two abundant catechins contained in green tea, were identified as major UGT inhibitors in these subfractions. Ki values were 2.0 and 0.8-1.0 μM, respectively, which were ~100x lower than concentrations measured in a 240-mL cup of hot tea prepared from the NIST leaf reference material. A biochemometric approach, which combines bioactivity data with chemometric analysis, was successfully applied to green tea for identifying intestinal UGT inhibitors that could precipitate an interaction with raloxifene and other UGT substrates (e.g., raltegravir, ezetimibe, and mycophenolic acid). This comprehensive approach could be applied to other natural products with drug interaction potential.

1 . Inhibition of UGT by (-)-Epigallocatechin Gallate (IC50 Determination) (id=NPDI-7el55g)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

4-methylumbelliferone

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Individual human intestinal microsomes -7999704

Results

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

UDPGA

Not available

Not available

100 µM

3.9-600 µM

2 . Inhibition of UGT by (-)-Epigallocatechin Gallate (Screening) (id=NPDI-EczRtA)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

4-methylumbelliferone

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

Results

Percent inhibition was estimated from Fig. S1.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Purified green tea catechins were tested as inhibitors of UGT enzymes as described in Gufford et al., 2014 (Drug Metab Dispos. 2014 Oct;42(10):1675-83); information regarding incubation volume, time, and protien linearity were obtain therein.
Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

150 µL

20 min

UDPGA

Available

Not available

100 µM

100 µM

Control Experiment Information

3 . Inhibition of UGT by (-)-Epicatechin Gallate (IC50 determination) (id=NPDI-AXdpJA)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

4-methylumbelliferone

epicatechin gallate

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

The precipitant used was (-)-epicatechin gallate.

Results

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

UDPGA

Not available

Not available

100 µM

3.9-800 µM

4 . Inhibition of UGT by (-)-Epicatechin Gallate (Screening) (id=NPDI-CWM_sQ)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

4-methylumbelliferone

epicatechin gallate

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

The precipitant used was (-)-epicatechin gallate.

Results

Percent inhibition was estimated from Fig. S1.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Purified green tea catechins were tested as inhibitors of UGT enzymes as described in Gufford et al., 2014 (Drug Metab Dispos. 2014 Oct;42(10):1675-83); information regarding incubation volume, time, and protein linearity were obtain therein.
Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

150 µL

20 min

UDPGA

Available

Not available

100 µM

100 µM

Control Experiment Information

5 . Unnamed Experiment (id=NPDI-y3-V_w)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

4-methylumbelliferone

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

Methanol extracts and (sub)fractions (five fractions obtained using a 4 g silica gel column and a hexane-chloroform-methanol mobile phase at 18 mL/min; normal phase chromatography) from four widely-avaliable commercial teas were used.

Results

Extracts, fractions, and subfractions from the four green teas inhibited intestinal UGT activity in a concentration-dependent manner (by 30-100% relative to vehicle control, estimated from Fig. 3). The UGT inhibitory constituents tended to reside in the more hydrophilic subfractions of the fraction prepared from the representative extract. (−)-Epigallocatechin gallate (EGCG) and (−)-epicatechin gallate (ECG), two abundant catechins contained in green tea, were identified as major UGT inhibitors in these subfractions.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Green tea extracts, fractions, and subfractions were tested as inhibitors of UGT enzymes as described in Gufford et al., 2014 (Drug Metab Dispos. 2014 Oct;42(10):1675-83); information regarding incubation volume, time, and protein linearity were obtain therein.
Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

150 µL

20 min

UDPGA

Available

Not available

100 µM

20, 60, and 180 µg/mL

6 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epicatechin (Screening) (id=NPDI-VlvwrQ)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

(-)-epicatechin

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epicatechin did not signficiantly inhibit the formation of raloxifene 6-glucuronide. Percent inhibition value was estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

7 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epicatechin (Screening) (id=NPDI-wl1otQ)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

(-)-epicatechin

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epicatechin did not signficiantly inhibit the formation of raloxifene 4'-glucuronide. Percent inhibition value was estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

8 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epigallocatechin (Screening) (id=NPDI-m23CAQ)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

(-)-epigallocatechin

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epigallocatechin did not signficiantly inhibit the formation of raloxifene 6-glucuronide. Percent inhibition value was estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

9 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epigallocatechin (Screening) (id=NPDI-Xe-X8A)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

(-)-epigallocatechin

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epigallocatechin did not signficiantly inhibit the formation of raloxifene 4'-glucuronide. Percent inhibition value was estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

10 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epigallocatechin Gallate (Ki determination) (id=NPDI-8CdNjg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

raloxifene 1513103

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

Using methods 1 and 2 provided by the authors, enterocyte concentrations for (-)-epigallocatechin gallate were estimated to be 17.2 and 0.60 µM, respectively, after administration of one bag of T21 green tea. With the Ki value of approximately 2 µM, the corresponding AUCi/AUC ratios were predicted to be 6.5 and 1.3, respectively.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.05 mg/mL

Commercially available

1410074

4 min

UDPGA

Not available

Not available

0.25-10 µM

1-16 µM

11 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epigallocatechin Gallate (Screening) (id=NPDI-rX0CIg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epigallocatechin gallate inhibited the formation of raloxifene 6-glucuronide by about 50%. Percent inhibition values were estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

12 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epigallocatechin Gallate (Ki determination) (id=NPDI-XIaDNg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

raloxifene 1513103

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

Using methods 1 and 2 provided by the authors, enterocyte concentrations for (-)-epigallocatechin gallate were estimated to be 17.2 and 0.60 µM, respectively, after administration of one bag of T21 green tea. With the Ki value of approximately 2 µM, the corresponding AUCi/AUC ratios were predicted to be 6.5 and 1.3, respectively.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.05 mg/mL

Commercially available

1410074

4 min

UDPGA

Not available

Not available

0.25-10 µM

1-16 µM

13 . Inhibition of UGT1A1, 1A10, and 1A8 by (-)-Epigallocatechin Gallate (Screening) (id=NPDI-uGwaFA)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015.

Results

At 10 µM (-)-epigallocatechin gallate inhibited the formation of raloxifene 4'-glucuronide by about 50%. Percent inhibition values were estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

14 . Inhibition of UGT1A1, 1A8, and 1A10 by (+)-catechin (Screening) (id=NPDI-ubCatg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

catechin 43012577

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-gallocatechin did not signficiantly inhibit the formation of raloxifene 6-glucuronide. Percent inhibition value was estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

15 . Inhibition of UGT1A1, 1A8, and 1A10 by (+)-catechin (Screening) (id=NPDI-TIvDHw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

catechin 43012577

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-gallocatechin did not signficiantly inhibit the formation of raloxifene 4'-glucuronide. Percent inhibition value was estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

16 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epicatechin Gallate (Screening) (id=NPDI-Hzxkxw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

epicatechin gallate

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epicatechin gallate inhibited the formation of raloxifene 6-glucuronide by about 70%. Percent inhibition values were estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

17 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epicatechin Gallate (Ki determination) (id=NPDI-WIQ_6A)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

raloxifene 1513103

epicatechin gallate

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

The precipitant used was (-)-epicatechin gallate. Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

Using methods 1 and 2 provided by the authors, enterocyte concentrations for (-)-epicatechin gallate were estimated to be 8.5 and 0.29 µM, respectively, after administration of one bag of T21 green tea. With the Ki value of approximately 1 µM, the corresponding AUCi/AUC ratios were predicted to be 6.5 and 1.3, respectively.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.05 mg/mL

Commercially available

1410074

4 min

UDPGA

Not available

Not available

0.25-10 µM

0.5-8 µM

18 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epicatechin Gallate (Ki determination) (id=NPDI-1nd-Ow)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

raloxifene 1513103

epicatechin gallate

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

The precipitant used was (-)-epicatechin gallate. Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

Using methods 1 and 2 provided by the authors, enterocyte concentrations for (-)-epicatechin gallate were estimated to be 8.5 and 0.29 µM, respectively, after administration of one bag of T21 green tea. With the Ki value of approximately 1 µM, the corresponding AUCi/AUC ratios were predicted to be 6.5 and 1.3, respectively.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.05 mg/mL

Commercially available

1410074

4 min

UDPGA

Not available

Not available

0.25-10 µM

0.5-8 µM

19 . Inhibition of UGT1A1, 1A8, and 1A10 by (-)-Epicatechin Gallate (Screening) (id=NPDI-WhE0iA)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — 50% inhibition vs. control

raloxifene 1513103

epicatechin gallate

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

The precipitant used was (-)-epicatechin gallate. Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

At 10 µM (-)-epicatechin gallate inhibited the formation of raloxifene 4'-glucuronide by about 65%. Percent inhibition values were estimated from Fig. S2.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

1410074

Not available

Not available

100 µM

Control Experiment Information

20 . Inhibition of UGT1A1 and 1A8 by Green Tea Leaf Extract (T21) (Ki determination) (id=NPDI-jljbXg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided.

raloxifene 1513103

raloxifene 6-glucuronide

  • UGT1A1 40782950
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Methanol extract of a widely avaliable commercial green tea leaf (T21, 200 mg) chemically similar to the National Institute of Standards and Technology (NIST) green tea leaf reference was used. Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.05 mg/mL

Commercially available

1410074

4 min

UDPGA

Not available

Not available

0.25-10 µM

2.5-40 µg/mL

21 . Inhibition of UGT1A1, 1A8, and 1A10 by Green Tea Leaf Extract (T21) (Ki determination) (id=NPDI-aqYl1g)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not provided

raloxifene 1513103

raloxifene 4'-glucuronide

  • UGT1A1 40782950
  • UGT1A10
  • UGT1A8

Cell fraction Pooled human intestinal microsomes -7999663

Methanol extract of a widely avaliable commercial green tea leaf (T21, 200 mg) chemically similar to the National Institute of Standards and Technology (NIST) green tea leaf reference was used. Information regarding enzymes involved in the formation of raloxifene metabolites was obtained from Gufford et al., 2015 (Drug Metab Dispos. 2015 Sep;43(9):1353-9).

Results

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.05 mg/mL

Commercially available

1410074

4 min

UDPGA

Not available

Not available

0.25-10 µM

2.5-40 µg/mL

22 . Inhibition of UGT by (-)-Epicatechin (Screening) (id=NPDI-cTDX2A)

In Vitro Enzyme Inhibition Experiment

Negligible Inhibition was detected.  Cutoff used — 50% inhibition vs. control

4-methylumbelliferone

(-)-epicatechin

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

Results

(-)-Epicatechin did not significantly inhibit UGT enzymes--observed UGT activity was 110% of control.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Purified green tea catechins were tested as inhibitors of UGT enzymes as described in Gufford et al., 2014 (Drug Metab Dispos. 2014 Oct;42(10):1675-83); information regarding incubation volume, time, and protien linearity were obtain therein.
Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

150 µL

20 min

UDPGA

Available

Not available

100 µM

100 µM

Control Experiment Information

23 . Inhibition of UGT by (-)-Gallocatechin (Screening) (id=NPDI-p3x0vg)

In Vitro Enzyme Inhibition Experiment

Negligible Inhibition was detected.  Cutoff used — 50% inhibition vs. control

4-methylumbelliferone

(-)-gallocatechin

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

Results

(-)-Gallocatechin did not significantly inhibit UGT enzymes--observed UGT activity was 105% of control.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Purified green tea catechins were tested as inhibitors of UGT enzymes as described in Gufford et al., 2014 (Drug Metab Dispos. 2014 Oct;42(10):1675-83); information regarding incubation volume, time, and protien linearity were obtain therein.
Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

150 µL

20 min

UDPGA

Available

Not available

100 µM

100 µM

Control Experiment Information

24 . Inhibition of UGT by (-)-Epigallocatechin (Screening) (id=NPDI-7pd4sA)

In Vitro Enzyme Inhibition Experiment

Negligible Inhibition was detected.  Cutoff used — 50% inhibition vs. control

4-methylumbelliferone

epigallocatechin

4-methylumbelliferone glucuronide

  • UGT

Cell fraction Pooled human intestinal microsomes -7999663

The precipitant used was (-)-epigallocatechin.

Results

(-)-Epigallocatechin did not significantly inhibit UGT enzymes--observed UGT activity was 110% of control.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Purified green tea catechins were tested as inhibitors of UGT enzymes as described in Gufford et al., 2014 (Drug Metab Dispos. 2014 Oct;42(10):1675-83); information regarding incubation volume, time, and protien linearity were obtain therein.
Bovine serum albumin (0.05%) was added into the incubation system.

0.2 mg/mL

Commercially available

1410074

150 µL

20 min

UDPGA

Available

Not available

100 µM

100 µM

Control Experiment Information