>> Главная

Differential effects and transport kinetics of ascorbate derivatives in leukemic cell lines.

Anticancer Res 1998 Jul-Aug;18(4A):2487-93    (ISSN: 0250-7005)

Koh WS; Lee SJ; Lee H; Park C; Park MH; Kim WS; Yoon SS; Park K; Hong SI; Chung MH; Park CH
Department of Medicine, Samsung Medical Center, Kangnam-ku Seoul, Korea.

In order to investigate the differential effects of ascorbate derivatives on leukemic cell growth, we examined their stabilities and transmembrane transport efficiencies. The growth of HL - 60 and U937 cells was dose-dependently inhibited by ascorbic acid and sodium ascorbate , but not by dehydroascorbic acid and magnesium ascorbyl 2 -phosphate up to 200 microM. The growth-suppression by ascorbic acid was dependent on its redox state, showing a complete or partial reversion by ascorbate oxidase or FeCl3 addition, respectively. Three different patterns of intracellular ascorbic acid accumulation were observed by HPLC according to the species of ascorbate derivative applied for the incubation. Compared with the reduced form of ascorbic acid, the oxidized forms (dehydroascorbic acid, ascorbic acid plus ascorbate oxidase or FeCl3) were rapidly transported into cells and readily degraded, while magnesium ascorbyl 2 -phosphate, a stable derivative of ascorbic acid, slowly elevated the intracellular level of ascorbic acid, reaching a plateau at 24 hours. We also measured the differential kinetics of ascorbic acid levels In culture supernatants following the addition of ascorbate derivatives . Ascorbic acid at 40, 10, or 1 microM was observed 3 hours following treatment with 100 microM of ascorbic acid, ascorbic acid plus FeCl3, or magnesium ascorbyl 2 -phosphate, respectively. No ascorbic acid was found in the culture supernatant treated with dehydroascorbic acid. This order of ascorbic acid concentrations in culture supernatant reflects their growth-inhibitory effects. Thus the growth inhibitory effect of ascorbic acid appears to be dependent on its concentration in culture medium rather than its intracellular concentration. In conclusion, the results in this study indicate that the differential effects of ascorbate derivatives appear to be due to the actual concentration differences of the reduced form of ascorbic acid in culture medium following their addition, which is determined by their stability and efficiency of cellular uptake.



Type a keyword and click on the 'Go' button to begin full-text search throughout the site.

 Printer-friendly page

Send page to a friend Send page to a friend

Bookmark this page Bookmark this page

>> Natural Health Care

>> Studies Worldwide

>> "Business With Disease"

>> International Campaign

>> Open Letter Campaign

>> Take Action

>> Features

 © 2019 Dr. Rath Health Foundation Send page to a friend contact Printer-friendly page Help Previous document Top of the page Function not available in this page Back to Homepage