45I-2 |
Antiproliferative activity of apples |
J. SUN and R. H. Liu. Dept. of Food Science, Cornell Univ., 165 Stocking Hall, Ithaca, NY 14853-7201 Anticancer compound screening of natural products using tumor cell lines has been commonly used to identify anticancer drugs. It has been recently reported that the inhibition of cancer cell proliferation by fruit extracts was indirectly caused by phenolic-induced H2O2 production in the cell culture media suggesting that many previously reported effects of flavonoids and phenolic compounds on cultured cells might be from an artifact of H2O2-induced oxidative stress. The objective of the present study was to determine if apple extracts induced H2O2 formation in common cell culture media, and to investigate if the antiproliferative activity of apple extracts was due to phenolic-induced H2O2 formation. Total phenolic content of apple extracts was measured using a modified colorimetric Folin-Ciocalteu method. The content of H2O2 in cell culture medium was determined by horseradish peroxidase-mediated H2O2 oxidation of phenol red assay. Antiproliferative activities of apple extracts were measured by the MTS-based cell proliferation assay. Apple extracts did not induce H2O2 formation in WME, DMEM, and DMEM/Ham F12 media with the cell culture conditions tested. Apple extract showed a strong antiproliferative activity on human HepG2 liver cancer cell growth when compared with the control culture (p<0.05). Cell proliferation was inhibited in a dose-dependant manner with a median effective dose EC50 of 56.6±0.29 mg/mL. Addition of catalase (1 Sigma U/mL) did not block the antiproliferative activity when compared to the apple extracts (p>0.05). H2O2 added to the culture medium at 100 µM did not inhibit cell proliferation in HepG2 liver cancer cells in vitro. Antiproliferative activity of apple extracts was not due to the phenolic-induced H2O2 production in cell culture media. Cell proliferation assays have been successfully used to screen anticancer compounds in conjunction with cytotoxicity assays and will continue to serve as an important model for initial anticancer drug screening from natural products.
Session 45I, Nutrition: General
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