Goldenseal (Hydrastis canadensis)
Human Cytochrome P450 Inhibition and Metabolic-Intermediate Complex Formation By Goldenseal Extract and Its Methylenedioxyphenyl Components
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The concurrent use of herbal medicinals with prescription and over-the-counter drugs carries a risk for unanticipated adverse drug-botanical pharmacokinetic interactions, particularly as a result of cytochrome P450 (P450) inhibition. Extracts of goldenseal (Hydrastis canadensis) containing approximately equal concentrations ( approximately 17 mM) of two methylenedioxyphenyl alkaloids, berberine and hydrastine, inhibited with increasing potency (CYP2C9) diclofenac 4'-hydroxylation, (CYP2D6) bufuralol 1'-hydroxylation, and (CYP3A4) testosterone 6beta-hydroxylation activities in human hepatic microsomes. The inhibition of testosterone 6beta-hydroxylation activity was noncompetitive with an apparent Ki of 0.11% extract. Of the methylenedioxyphenyl alkaloids, berberine (IC50 = 45 microM) was the more inhibitory toward bufuralol 1'-hydroxylation and hydrastine (IC50 approximately 350 microM for both isomers), toward diclofenac 4'-hydroxylation. For testosterone 6beta-hydroxylation, berberine was the least inhibitory component (IC50 approximately 400 microM). Hydrastine inhibited testosterone 6beta-hydroxylation with IC50 values for the (+)- and (-)-isomers of 25 and 30 microM, respectively. For (-)-hydrastine, an apparent Ki value of 18 microM without preincubation and an NADPH-dependent mechanism-based inhibition with a kinactivation of 0.23 min(-1) and a KI of approximately 110 microM were determined. Cytochrome P450 metabolic-intermediate (MI) complex formation could be demonstrated for both hydrastine isomers. With expressed P450 isoforms, hydrastine formed a P450 MI complex with CYP2C9, CYP2D6, and CYP3A4. Coexpression of cytochrome b5 with the P450 isoforms enhanced the rate but not the extent of P450 MI complex formation.
1 . 2D6 Inhibition by (-) Hydrastine (id=NPDI-UaWFPQ)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2D6 4173631
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 4b at 1000 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
1 mg/mL
Commercially available
30 min
NADPH
25 μM
No NADPH with precipitant
10, 100, and 1,000 μM
2 . 2D6 Inhibition by Berberine (id=NPDI-LNDazQ)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — Not Specified
- CYP2D6 4173631
Cell fraction Pooled human liver microsomes -7999662
Results
Estimate at 500 μM Fig 4b
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
1 mg/mL
Commercially available
30 min
NADPH
25 μM
No NADPH with precipitant
10, 100, and 500 μM
3 . 2D6 Inhibition by GS Extract (id=NPDI-qzY27Q)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2D6 4173631
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 2 Estimate
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
1 mg/mL
Commercially available
30 min
NADPH
25 μM
No NADPH with precipitant
4 . 2D6 Inhibition by (+) Hydrastine (id=NPDI-w-6ghw)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2D6 4173631
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 4b (+) hydrastine at 1000 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
1 mg/mL
Commercially available
30 min
NADPH
25 μM
No NADPH with precipitant
10, 100, and 1,000 μM
5 . 2C9 Inhibition by (-) Hydrastine (id=NPDI-wdarow)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2C9 4309227
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 4c at 1000 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.5 mg/mL
Commercially available
30 min
NADPH
100 μM
No NADPH with precipitant
10, 100, and 1000 μM
6 . 2C9 Inhibition by Berberine (id=NPDI-iSHQYQ)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2C9 4309227
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 4c estimation at 500 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.5 mg/mL
Commercially available
30 min
NADPH
100 μM
No NADPH with precipitant
10, 100, and 500 μM
7 . 2C9 Inhibition by GS Extract (id=NPDI--K80vw)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2C9 4309227
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 2 difference estimate at 1% of extract
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.5 mg/mL
Commercially available
30 min
NADPH
100 μM
No NADPH with precipitant
8 . 2C9 Inhibition by (+) Hydrastine (id=NPDI-3M10oA)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP2C9 4309227
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 4c at 1000 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.5 mg/mL
Commercially available
30 min
NADPH
100 μM
No NADPH with precipitant
10, 100, and 1000 μM
9 . 3A4 Inhibition by (-) Hydrastine (id=NPDI-CDvKlQ)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP3A4 4306811
Cell fraction Pooled human liver microsomes -7999662
Results
fig 4a at 1000 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.2 mg/mL
Commercially available
15 min
NADPH
200 μM
No NADPH with precipitant
10, 100, and 1000 μM
10 . 3A4 Inhibition by Berberine (id=NPDI-_D6yiA)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP3A4 4306811
Cell fraction Pooled human liver microsomes -7999662
Results
Estimate at 500 μM (Fig 4a)
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.2 mg/mL
Commercially available
15 min
NADPH
200 μM
No NADPH with precipitant
10, 100, and 500 μM
11 . 3A4 Inhibition by GS Extract (id=NPDI-OCQ06Q)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP3A4 4306811
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 2 at 1%
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.2 mg/mL
Commercially available
15 min
NADPH
200 μM
No NADPH with precipitant
12 . 3A4 Inhibition by (+) Hydrastine (id=NPDI-39rhWg)
In Vitro Enzyme Inhibition Experiment
Inhibition was detected. Cutoff used — not specified
- CYP3A4 4306811
Cell fraction Pooled human liver microsomes -7999662
Results
Fig 4a at 1000 μM
| Sample | Compound measured | Value | Measurement | Study sequence | Additional information | N replicates |
|---|
Experimental Conditions
0.2 mg/mL
Commercially available
15 min
NADPH
200 μM
No NADPH with precipitant
10, 100, and 1000 μM