Glutathione S-Transferase (GST)

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] ?
Bibliography
1. The inhibition of human glutathione S-transferases activity by plant polyphenolic compounds ellagic acid and curcumin.
Hayeshi R, Mutingwende I, Mavengere W, Masiyanise V, Mukanganyama S. PubMed PMID: 17046132
2. Identification of N-acetylcysteine as a new substrate for rat liver microsomal glutathione transferase. A study of thiol ligands.
Weinander R, Anderson C, Morgenstern R. PubMed PMID 8276873
3. Effects of dietary curcumin on glutathione S-transferase and malondialdehyde-DNA adducts in rat liver and colon mucosa: relationship with drug levels.
Sharma RA, Ireson CR, Verschoyle RD, Hill KA, Williams ML, Leuratti C, Manson MM, Marnett LJ, Steward WP, Gescher A. PubMed PMID 11350917
4. Inhibition of glutathione S-transferase activity in human melanoma cells by alpha,beta-unsaturated carbonyl derivatives. Effects of acrolein, cinnamaldehyde, citral, crotonaldehyde, curcumin, ethacrynic acid, and trans-2-hexenal.
Iersel ML, Ploemen JP, Struik I, van Amersfoort C, Keyzer AE, Schefferlie JG, van Bladeren PJ. PubMed PMID 8950226
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License