Glutathione S-transferase (GST) enzymes (EC number 2.5.1.18) catalyze the conjugation of reduced glutathione (GSH) (using a sulfhydryl group) to electrophilic centers on a wide variety of substrates.
N-acetylcysteine has been shown to act as a substrate for GST in place of glutathione in rat liver in vitro.[2]
Note that some in vitro studies using human cells show that curcumin inhibits GST[1] while others found dietary curcumin increased hepatic GST by 16% in rats[3]. Curcumin's effects need to be verified in humans in vivo to determine what action it actually has in humans; in vitro tests do not always show the same results as in vivo tests. It's possible that curcumin first inhibits GST and then induces GST. This type of action is sometimes seen in compounds that induce enzymes.
GSTA1-1 Inhibitors | Strength | Dosage | Verified in Man |
---|---|---|---|
Curcumin [1] (induction is also possible)[3] | IC50<=5 microM | ? | ? |
Daidzein [1] (in Kudzu) | ? | ? | ? |
Ellagic acid [1] | IC50<=5 microM | ? | ? |
GSTA2-2 Inhibitors | Strength | Dosage | Verified in Man |
Curcumin [1] (induction is also possible)[3] | IC50<=5 microM | ? | ? |
Ellagic acid [1] | IC50<=5 microM | ? | ? |
Resveratrol [1] | ? | ? | ? |
GSTM1-1 Inhibitors | Strength | Dosage | Verified in Man |
Curcumin [1] (induction is also possible)[3] | IC50<=5 microM | ? | ? |
(+)-catechin hydrate [1] | ? | ? | ? |
Daidzein [1] (in Kudzu) | ? | ? | ? |
Ellagic acid [1] | IC50<=5 microM | ? | ? |
Ferulic acid [1] | ? | ? | ? |
Genistein [1] (in Kudzu) | ? | ? | ? |
Kaempferol [1] | ? | ? | ? |
Quercetin [1] | ? | ? | ? |
Resveratrol [1] | ? | ? | ? |
GSTM2-2 Inhibitors | Strength | Dosage | Verified in Man |
Curcumin [1] (induction is also possible)[3] | IC50<=5 microM | ? | ? |
(+)-catechin hydrate [1] | ? | ? | ? |
Ellagic acid [1] | IC50<=5 microM | ? | ? |
Genistein [1] (in Kudzu) | ? | ? | ? |
Kaempferol [1] | ? | ? | ? |
Quercetin [1] | ? | ? | ? |
Resveratrol [1] | ? | ? | ? |
GSTP1-1 Inhibitors | Strength | Dosage | Verified in Man |
Cinnamaldehyde (in cinnamon oil) | Moderate inhibition[4] | ? | ? |
Crotonaldehyde | Moderate inhibition[4] | ? | ? |
Curcumin [1] (induction is also possible)[3] | 96% inhibition | 25 microM[4] | ? |
Daidzein [1] (in Kudzu) | ? | ? | ? |
Ellagic acid [1] | IC50<=5 microM | ? | ? |
Ethacrynic acid | 67% inhibition | 25 microM[4] | ? |
Resveratrol [1] | ? | ? | ? |
Trans-2-hexenal | 61% inhibition | 25 microM[4] | ? |