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Cheng-an Shih - One of the best experts on this subject based on the ideXlab platform.

  • inhibitory effect of curcumin on xanthine dehydrogenase oxidase induced by Phorbol 12 myristate 13 acetate in njh3t3 cells
    Carcinogenesis, 1994
    Co-Authors: Jen-kun Lin, Cheng-an Shih
    Abstract:

    Treatment of NIH3T3 cells with the tumor promoter Phorbol-12-myristate-13-acetate (PMA) results within 30 min in a 1.8-fold elevation of xanthine oxidase (XO) activity, an enzyme capable of generating reactive oxygen species such as superoxide and hydrogen peroxide. Simultaneous administration of 2 and 10 microM curcumin with 100 ng/ml PMA inhibits PMA-induced increases in XO activity measured 30 min later by 22.7% and 36.5%, respectively. The PMA-induced conversion of xanthine dehydrogenase (XD) to XO is reduced by curcumin to the basal level noted in untreated cells. Activity of XO is remarkably inhibited by curcumin in vitro, but not by its structurally related compounds caffeic acid, chlorogenic acid and ferulic acid. Based on these findings, induction of XO activity is deemed to be one of the major causative elements in PMA-mediated tumor promotion, and the major inhibitory mechanism of curcumin on PMA-induced increases in XD/XO enzyme activities is through direct inactivation at the protein level.

  • Inhibitory effect of curcumin on xanthine dehydrogenase/oxidase induced by Phorbol-12-myristate-13-acetate in NJH3T3 cells
    Carcinogenesis, 1994
    Co-Authors: Jen-kun Lin, Cheng-an Shih
    Abstract:

    Treatment of NIH3T3 cells with the tumor promoter Phorbol-12-myristate-13-acetate (PMA) results within 30 min in a 1.8-fold elevation of xanthine oxidase (XO) activity, an enzyme capable of generating reactive oxygen species such as superoxide and hydrogen peroxide. Simultaneous administration of 2 and 10 microM curcumin with 100 ng/ml PMA inhibits PMA-induced increases in XO activity measured 30 min later by 22.7% and 36.5%, respectively. The PMA-induced conversion of xanthine dehydrogenase (XD) to XO is reduced by curcumin to the basal level noted in untreated cells. Activity of XO is remarkably inhibited by curcumin in vitro, but not by its structurally related compounds caffeic acid, chlorogenic acid and ferulic acid. Based on these findings, induction of XO activity is deemed to be one of the major causative elements in PMA-mediated tumor promotion, and the major inhibitory mechanism of curcumin on PMA-induced increases in XD/XO enzyme activities is through direct inactivation at the protein level.

Jen-kun Lin - One of the best experts on this subject based on the ideXlab platform.

  • inhibitory effect of curcumin on xanthine dehydrogenase oxidase induced by Phorbol 12 myristate 13 acetate in njh3t3 cells
    Carcinogenesis, 1994
    Co-Authors: Jen-kun Lin, Cheng-an Shih
    Abstract:

    Treatment of NIH3T3 cells with the tumor promoter Phorbol-12-myristate-13-acetate (PMA) results within 30 min in a 1.8-fold elevation of xanthine oxidase (XO) activity, an enzyme capable of generating reactive oxygen species such as superoxide and hydrogen peroxide. Simultaneous administration of 2 and 10 microM curcumin with 100 ng/ml PMA inhibits PMA-induced increases in XO activity measured 30 min later by 22.7% and 36.5%, respectively. The PMA-induced conversion of xanthine dehydrogenase (XD) to XO is reduced by curcumin to the basal level noted in untreated cells. Activity of XO is remarkably inhibited by curcumin in vitro, but not by its structurally related compounds caffeic acid, chlorogenic acid and ferulic acid. Based on these findings, induction of XO activity is deemed to be one of the major causative elements in PMA-mediated tumor promotion, and the major inhibitory mechanism of curcumin on PMA-induced increases in XD/XO enzyme activities is through direct inactivation at the protein level.

  • Inhibitory effect of curcumin on xanthine dehydrogenase/oxidase induced by Phorbol-12-myristate-13-acetate in NJH3T3 cells
    Carcinogenesis, 1994
    Co-Authors: Jen-kun Lin, Cheng-an Shih
    Abstract:

    Treatment of NIH3T3 cells with the tumor promoter Phorbol-12-myristate-13-acetate (PMA) results within 30 min in a 1.8-fold elevation of xanthine oxidase (XO) activity, an enzyme capable of generating reactive oxygen species such as superoxide and hydrogen peroxide. Simultaneous administration of 2 and 10 microM curcumin with 100 ng/ml PMA inhibits PMA-induced increases in XO activity measured 30 min later by 22.7% and 36.5%, respectively. The PMA-induced conversion of xanthine dehydrogenase (XD) to XO is reduced by curcumin to the basal level noted in untreated cells. Activity of XO is remarkably inhibited by curcumin in vitro, but not by its structurally related compounds caffeic acid, chlorogenic acid and ferulic acid. Based on these findings, induction of XO activity is deemed to be one of the major causative elements in PMA-mediated tumor promotion, and the major inhibitory mechanism of curcumin on PMA-induced increases in XD/XO enzyme activities is through direct inactivation at the protein level.

T. S. Gaginella - One of the best experts on this subject based on the ideXlab platform.

  • Colonic inflammation in the rabbit induced by Phorbol-12-myristate-13-acetate
    Inflammation, 1990
    Co-Authors: D. J. Fretland, D. L. Widomski, S. Levin, T. S. Gaginella
    Abstract:

    Neutrophil (PMNL) infiltration of inflamed colonic tissue is a prominent feature of human inflammatory bowel disease (IBD). Colitis was established in New Zealand white rabbits by the intrarectal instillation of 1.5 mg/kg (in 10 ml 20% ethanol) Phorbol-12-myristate-13-acetate (PMA) and assessed by visual grading of colonic inflammation, levels of the neutrophil marker enzyme myeloperoxidase (MPO), and histological examination. After 24 h there was a significant ( P

Yu Jung Choi - One of the best experts on this subject based on the ideXlab platform.

  • galangin and kaempferol suppress Phorbol 12 myristate 13 acetate induced matrix metalloproteinase 9 expression in human fibrosarcoma ht 1080 cells
    Molecules and Cells, 2015
    Co-Authors: Yu Jung Choi
    Abstract:

    Matrix metalloproteinase (MMP)-9 degrades type IV collagen in the basement membrane and plays crucial roles in several pathological implications, including tumorigenesis and inflammation. In this study, we analyzed the effect of flavonols on MMP-9 expression in Phorbol-12-myristate-13-acetate (PMA)-induced human fibrosarcoma HT-1080 cells. Galangin and kaempferol efficiently decreased MMP-9 secretion, whereas fisetin only weakly decreased its secretion. Galangin and kaempferol did not affect cell viability at concentrations up to 30 μM. Luciferase reporter assays showed that galangin and kaempferol decrease transcription of MMP-9 mRNA. Moreover, galangin and kaempferol strongly reduce IκBα phosphorylation and significantly decrease JNK phosphorylation. These results indicate that galangin and kaempferol suppress PMA-induced MMP-9 expression by blocking activation of NF-κB and AP-1. Therefore, these flavonols could be used as chemopreventive agents to lower the risk of diseases involving MMP-9.

D. J. Fretland - One of the best experts on this subject based on the ideXlab platform.

  • Colonic inflammation in the rabbit induced by Phorbol-12-myristate-13-acetate
    Inflammation, 1990
    Co-Authors: D. J. Fretland, D. L. Widomski, S. Levin, T. S. Gaginella
    Abstract:

    Neutrophil (PMNL) infiltration of inflamed colonic tissue is a prominent feature of human inflammatory bowel disease (IBD). Colitis was established in New Zealand white rabbits by the intrarectal instillation of 1.5 mg/kg (in 10 ml 20% ethanol) Phorbol-12-myristate-13-acetate (PMA) and assessed by visual grading of colonic inflammation, levels of the neutrophil marker enzyme myeloperoxidase (MPO), and histological examination. After 24 h there was a significant ( P