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Curcumin inhibits glyoxalase 1: a possible link to its anti-inflammatory and anti-tumor activity.

Santel T, Pflug G, Hemdan NY, Schäfer A, Hollenbach M, Buchold M, Hintersdorf A, Lindner I, Otto A, Bigl M, Oerlecke I, Hutschenreuther A, Hutschenreuter A, Sack U, Huse K, Groth M, Birkemeyer C, Schellenberger W, Gebhardt R, Platzer M, Weiss T, Vijayalakshmi MA, Krüger M, Birkenmeier G - PLoS ONE (2008)

Bottom Line: Results of enzyme kinetics revealed that curcumin, compared to the polyphenols quercetin, myricetin, kaempferol, luteolin and rutin, elicited a stronger competitive inhibitory effect on Glo1 (K(i) = 5.1+/-1.4 microM).Moreover, whereas curcumin was found to hamper the growth of breast cancer (JIMT-1, MDA-MB-231), prostate cancer PC-3 and brain astrocytoma 1321N1 cells, no effect on growth or vitality of human primary hepatocytes was elucidated.The results described herein provide new insights into curcumin's biological activities as they indicate that inhibition of Glo1 by curcumin may result in non-tolerable levels of MGO and GSH, which, in turn, modulate various metabolic cellular pathways including depletion of cellular ATP and GSH content.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemistry, University of Leipzig, Leipzig, Germany.

ABSTRACT

Background: Glyoxalases (Glo1 and Glo2) are involved in the glycolytic pathway by detoxifying the reactive methylglyoxal (MGO) into D-lactate in a two-step reaction using glutathione (GSH) as cofactor. Inhibitors of glyoxalases are considered as anti-inflammatory and anti-carcinogenic agents. The recent finding that various polyphenols modulate Glo1 activity has prompted us to assess curcumin's potency as an Glo1 inhibitor.

Methodology/principal findings: Cultures of whole blood cells and tumor cell lines (PC-3, JIM-1, MDA-MD 231 and 1321N1) were set up to investigate the effect of selected polyphenols, including curcumin, on the LPS-induced cytokine production (cytometric bead-based array), cell proliferation (WST-1 assay), cytosolic Glo1 and Glo2 enzymatic activity, apoptosis/necrosis (annexin V-FITC/propidium iodide staining; flow cytometric analysis) as well as GSH and ATP content. Results of enzyme kinetics revealed that curcumin, compared to the polyphenols quercetin, myricetin, kaempferol, luteolin and rutin, elicited a stronger competitive inhibitory effect on Glo1 (K(i) = 5.1+/-1.4 microM). Applying a whole blood assay, IC(50) values of pro-inflammatory cytokine release (TNF-alpha, IL-6, IL-8, IL-1beta) were found to be positively correlated with the K(i)-values of the aforementioned polyphenols. Moreover, whereas curcumin was found to hamper the growth of breast cancer (JIMT-1, MDA-MB-231), prostate cancer PC-3 and brain astrocytoma 1321N1 cells, no effect on growth or vitality of human primary hepatocytes was elucidated. Curcumin decreased D-lactate release by tumor cells, another clue for inhibition of intracellular Glo1.

Conclusions/significance: The results described herein provide new insights into curcumin's biological activities as they indicate that inhibition of Glo1 by curcumin may result in non-tolerable levels of MGO and GSH, which, in turn, modulate various metabolic cellular pathways including depletion of cellular ATP and GSH content. This may account for curcumin's potency as an anti-inflammatory and anti-tumor agent. The findings support the use of curcumin as a potential therapeutic agent.

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Effect of polyphenols on IL-1β release from LPS-stimulated blood cells.Heparinized whole blood was stimulated by LPS in the absence or presence of polyphenols at increasing concentrations and incubated for 6 h at 37°C with 5% CO2. (A) Released IL-1β as measured in cell supernatants. Samples without additives but LPS were set at 100%. (B) The calculated LD50 values of the respective polyphenols. Data represent mean±S.D. of independent experiments (n = 6).
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pone-0003508-g002: Effect of polyphenols on IL-1β release from LPS-stimulated blood cells.Heparinized whole blood was stimulated by LPS in the absence or presence of polyphenols at increasing concentrations and incubated for 6 h at 37°C with 5% CO2. (A) Released IL-1β as measured in cell supernatants. Samples without additives but LPS were set at 100%. (B) The calculated LD50 values of the respective polyphenols. Data represent mean±S.D. of independent experiments (n = 6).

Mentions: Polyphenols are known for their anti-inflammatory effects on immune cells. To compare the effect of curcumin with other polyphenols displaying flavonoid structure, we applied whole blood assays whereby monocytes were stimulated with LPS at 37°C/5% CO2 and incubated for 6 h (Fig. 2). LPS-stimulated blood cells release pro-inflammatory cytokines such as TNF-α, IL-6, IL-1β and IL-8. Upon addition of curcumin and other selected flavonoids at increasing concentrations to the cultured cells, we observed a strong suppression of the pro-inflammatory cytokine release as exemplified by IL-1β (Fig. 2). The results of the current study rank curcumin at the top of the investigated polyphenols with respect to inhibition of pro-inflammatory cytokine production. IC50 values of 7.9 µM, 20 µM, 34.6 µM and 68 µM have been estimated for curcumin, quercetin, kaempferol, and luteolin, respectively. None of these compounds was found to induce IL-1β release in the absence of LPS. Moreover, at concentrations above 200 µM, these compounds induced red blood cell lysis. A strong positive correlation was found between the anti-inflammatory activity (IC50) and the in vitro Ki-values of curcumin, quercetin, kaempferol and luteolin (Spearman's R = 0.90) indicating that Glo1 inhibition may be a possible mechanism to explain the anti-inflammatory effects of these polyphenols.


Curcumin inhibits glyoxalase 1: a possible link to its anti-inflammatory and anti-tumor activity.

Santel T, Pflug G, Hemdan NY, Schäfer A, Hollenbach M, Buchold M, Hintersdorf A, Lindner I, Otto A, Bigl M, Oerlecke I, Hutschenreuther A, Hutschenreuter A, Sack U, Huse K, Groth M, Birkemeyer C, Schellenberger W, Gebhardt R, Platzer M, Weiss T, Vijayalakshmi MA, Krüger M, Birkenmeier G - PLoS ONE (2008)

Effect of polyphenols on IL-1β release from LPS-stimulated blood cells.Heparinized whole blood was stimulated by LPS in the absence or presence of polyphenols at increasing concentrations and incubated for 6 h at 37°C with 5% CO2. (A) Released IL-1β as measured in cell supernatants. Samples without additives but LPS were set at 100%. (B) The calculated LD50 values of the respective polyphenols. Data represent mean±S.D. of independent experiments (n = 6).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2567432&req=5

pone-0003508-g002: Effect of polyphenols on IL-1β release from LPS-stimulated blood cells.Heparinized whole blood was stimulated by LPS in the absence or presence of polyphenols at increasing concentrations and incubated for 6 h at 37°C with 5% CO2. (A) Released IL-1β as measured in cell supernatants. Samples without additives but LPS were set at 100%. (B) The calculated LD50 values of the respective polyphenols. Data represent mean±S.D. of independent experiments (n = 6).
Mentions: Polyphenols are known for their anti-inflammatory effects on immune cells. To compare the effect of curcumin with other polyphenols displaying flavonoid structure, we applied whole blood assays whereby monocytes were stimulated with LPS at 37°C/5% CO2 and incubated for 6 h (Fig. 2). LPS-stimulated blood cells release pro-inflammatory cytokines such as TNF-α, IL-6, IL-1β and IL-8. Upon addition of curcumin and other selected flavonoids at increasing concentrations to the cultured cells, we observed a strong suppression of the pro-inflammatory cytokine release as exemplified by IL-1β (Fig. 2). The results of the current study rank curcumin at the top of the investigated polyphenols with respect to inhibition of pro-inflammatory cytokine production. IC50 values of 7.9 µM, 20 µM, 34.6 µM and 68 µM have been estimated for curcumin, quercetin, kaempferol, and luteolin, respectively. None of these compounds was found to induce IL-1β release in the absence of LPS. Moreover, at concentrations above 200 µM, these compounds induced red blood cell lysis. A strong positive correlation was found between the anti-inflammatory activity (IC50) and the in vitro Ki-values of curcumin, quercetin, kaempferol and luteolin (Spearman's R = 0.90) indicating that Glo1 inhibition may be a possible mechanism to explain the anti-inflammatory effects of these polyphenols.

Bottom Line: Results of enzyme kinetics revealed that curcumin, compared to the polyphenols quercetin, myricetin, kaempferol, luteolin and rutin, elicited a stronger competitive inhibitory effect on Glo1 (K(i) = 5.1+/-1.4 microM).Moreover, whereas curcumin was found to hamper the growth of breast cancer (JIMT-1, MDA-MB-231), prostate cancer PC-3 and brain astrocytoma 1321N1 cells, no effect on growth or vitality of human primary hepatocytes was elucidated.The results described herein provide new insights into curcumin's biological activities as they indicate that inhibition of Glo1 by curcumin may result in non-tolerable levels of MGO and GSH, which, in turn, modulate various metabolic cellular pathways including depletion of cellular ATP and GSH content.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemistry, University of Leipzig, Leipzig, Germany.

ABSTRACT

Background: Glyoxalases (Glo1 and Glo2) are involved in the glycolytic pathway by detoxifying the reactive methylglyoxal (MGO) into D-lactate in a two-step reaction using glutathione (GSH) as cofactor. Inhibitors of glyoxalases are considered as anti-inflammatory and anti-carcinogenic agents. The recent finding that various polyphenols modulate Glo1 activity has prompted us to assess curcumin's potency as an Glo1 inhibitor.

Methodology/principal findings: Cultures of whole blood cells and tumor cell lines (PC-3, JIM-1, MDA-MD 231 and 1321N1) were set up to investigate the effect of selected polyphenols, including curcumin, on the LPS-induced cytokine production (cytometric bead-based array), cell proliferation (WST-1 assay), cytosolic Glo1 and Glo2 enzymatic activity, apoptosis/necrosis (annexin V-FITC/propidium iodide staining; flow cytometric analysis) as well as GSH and ATP content. Results of enzyme kinetics revealed that curcumin, compared to the polyphenols quercetin, myricetin, kaempferol, luteolin and rutin, elicited a stronger competitive inhibitory effect on Glo1 (K(i) = 5.1+/-1.4 microM). Applying a whole blood assay, IC(50) values of pro-inflammatory cytokine release (TNF-alpha, IL-6, IL-8, IL-1beta) were found to be positively correlated with the K(i)-values of the aforementioned polyphenols. Moreover, whereas curcumin was found to hamper the growth of breast cancer (JIMT-1, MDA-MB-231), prostate cancer PC-3 and brain astrocytoma 1321N1 cells, no effect on growth or vitality of human primary hepatocytes was elucidated. Curcumin decreased D-lactate release by tumor cells, another clue for inhibition of intracellular Glo1.

Conclusions/significance: The results described herein provide new insights into curcumin's biological activities as they indicate that inhibition of Glo1 by curcumin may result in non-tolerable levels of MGO and GSH, which, in turn, modulate various metabolic cellular pathways including depletion of cellular ATP and GSH content. This may account for curcumin's potency as an anti-inflammatory and anti-tumor agent. The findings support the use of curcumin as a potential therapeutic agent.

Show MeSH
Related in: MedlinePlus