Your browser doesn't support javascript.
loading
The effect of curcumin on glutathione-linked enzymes in K562 human leukemia cells.
Singhal, S S; Awasthi, S; Pandya, U; Piper, J T; Saini, M K; Cheng, J Z; Awasthi, Y C.
Afiliação
  • Singhal SS; Department of Internal Medicine, The University of Texas Medical Branch, Galveston 77555, USA.
Toxicol Lett ; 109(1-2): 87-95, 1999 Sep 20.
Article em En | MEDLINE | ID: mdl-10514034
Curcumin, an antioxidant present in the spice turmeric (Curcuma longa), has been shown to inhibit chemical carcinogenesis in animal models and has been shown to be an anti-inflammatory agent. While mechanisms of its biological activities are not understood, previous studies have shown that it modulates glutathione (GSH)-linked detoxification mechanisms in rats. In the present studies, we have examined the effects of curcumin on GSH-linked enzymes in K562 human leukemia cells. One micromolar curcumin in medium (16 h) did not cause any noticeable change in glutathione peroxidase (GPx), glutathione reductase, and glucose-6-phosphate dehydrogenase activities. Gamma-glutamyl-cysteinyl synthetase activity was induced 1.6-fold accompanied by a 1.2-fold increase in GSH levels. GSH S-transferase (GST) activities towards 1-chloro-2,4-dinitrobenzene, and 4-hydroxynonenal (4HNE) were increased in curcumin-treated cells 1.3- and 1.6-fold, respectively (P = 0.05). The GST isozyme composition of K562 cells was determined as follows: 66% of GST Pl-1, 31% of Mu class GST(s), and 3% of an anionic Alpha-class isozyme hGST 5.8, which was immunologically similar to mouse GSTA4-4 and displayed substrate preference for 4HNE. The isozyme hGST 5.8 appeared to be preferentially induced by curcumin, as indicated by a relatively greater increase in activity toward 4HNE. Immunoprecipitation showed that GPx activity expressed by GST 5.8 contributed significantly (approximately 50%) to the total cytosolic GPx activity of K562 cells to lipid hydroperoxides. Taken together, these results suggest that GSTs play a major role in detoxification of lipid peroxidation products in K562 cells, and that these enzymes are modulated by curcumin.
Assuntos
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Leucemia / Curcumina / Glutationa / Antineoplásicos Fitogênicos / Antioxidantes Limite: Humans Idioma: En Ano de publicação: 1999 Tipo de documento: Article
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Leucemia / Curcumina / Glutationa / Antineoplásicos Fitogênicos / Antioxidantes Limite: Humans Idioma: En Ano de publicação: 1999 Tipo de documento: Article