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Nutrition: Antioxidant activity of fresh apples
MARIAN V. EBERHARDT1, CHANG YONG LEE1 & RUI HAI LIU1
Department of Food Science, 108 Stocking
Hall, Cornell University, Ithaca, New York 14853-7201, USA
Abstract: Vitamin C is used as a dietary supplement because of its
antioxidant activity, although a high dose (500 mg) may act as a pro-oxidant
in the body. Here we show that 100 g of fresh apples has an antioxidant
activity equivalent to 1,500 mg of vitamin C, and that
inhibit the growth of colon- and liver- cancer cells in vitro
in a dose-dependent manner.
Objective: The antioxidant
activity of 100g of fresh apple has been found to be equal to that of a
1,500-mg dose of vitamin C. This study assesses the growth inhibiting
effects of whole apple extracts on in vitro
colon- and liver cancer cells, based on dose dependent comparisons.
Methods and Results: The
flavonoids contents of fresh Red Delicious
determined using an 80% acetone extraction process. With and without skin
the values obtained, respectively, were found to be 290.2+4.2 and
219.8+1.8 mg phenolics, and 142.7+3.7 and 97.6+3.9 mg
flavonoids per 100g apple. A total oxyradical-scavenging capacity (TOSC)
assay was used to measure apple-antioxidant capacity. This data reveals
that a 1g portion of apples with skin contains a total antioxidant capacity
of 83.3+8.9 TOSC. The TOSC value unveils the antioxidant capacity of
100g of apple to be equal to that of 1,500mg of vitamin C. Apples with
skin contain a mere 5.7-mg of vitamin C, therefore leaving almost all of the
antioxidant activity in apples to be due to
colon-cancer cell Caco-2 was then
treated with variable amounts of
apple extracts equivalent to 0, 5, 10, 20,
30, 40, and 50 mg ml^-1. Cell proliferation was inhibited by this treatment
in a dose dependent manner when
extract concentrations exceeded 20 mg ml^-1,
and when given optimal response time.
The proliferation of another cancer
cell, HepG2 human liver tumor cell, was also inhibited
when exposed to apple
extractconcentrations at 50 mg ml^-1. The
extract from apples containing skin had the ability to
significantly reduce tumor cell proliferation in
comparison toextracts from apples without skin.
Additional information on this study from
OncoLink Cancer News:
In the June 22nd issue of Nature, Dr. Rui Hai Liu and
colleagues report that they used material extracted from fresh Red Delicious
apples to treat a colon-cancer cell line, Caco-2. "Cell proliferation was
inhibited in a dose-dependent manner after exposure to apple-extract
concentrations above 20 mg/mL," they write. "At 50 mg/mL, inhibition was
43%...and 29%...for apples with [and] without skin, respectively."
The team also tested
apple extract on HepG2 human liver tumor cells. They
found that tumor proliferation was inhibited 57% by
extract containing apple
skin and 40% by extract not containing skin.
affects antioxidant properties of apples in Caco-2 cells.
Tarozzi A, Marchesi A, Cantelli-Forti G, Hrelia P.
Department of Pharmacology, University of Bologna, 40126 Bologna, Italy.
Data on the composition of phenolic antioxidant compounds present in food
plants and assessment of their activity are essential for epidemiological
explanation of the health benefits of fruit and vegetables. Various factors
such as cultivation methods, industrial processing, and
storage may affect
the final concentrations of phytochemicals in food plants and their
bioactivity. This study investigated the influence of commercial
cold-storage periods on the antioxidant properties of apples grown either by
organic or integrated systems. In both cases,
total phenolics and total
antioxidant activity decreased only in the first 3 mo and only in apples
with skin (P < 0.05), suggesting that cold storage rapidly impoverishes
these properties in skin but not in pulp. Assessment of antioxidant
bioactivity in vitro, measured in terms of intracellular antioxidant,
antiproliferative activity in
human colon carcinoma (Caco-2) cells (differentiated to normal intestinal epithelia for
intracellular antioxidant and cytoprotective effects), showed
time-related decreases over 6 mo of cold storage for all 3 parameters (P <
0.01), irrespective of the cultivation system. These findings with
integrated and organic apples further support the concept that organic
systems of cultivation do not generally provide real health benefits.
Moreover, the data from the present study clearly show that
factors such as
cold storage may affect the antioxidant properties of apples.
Epidemiological studies on the cancer-preventive benefits of fruits and
vegetables should take into account the cold-storage bias for apples, and
possibly for other products.
PMID: 15113953 [PubMed - indexed for MEDLINE]
J Agric Food Chem.
2004 Dec 1;52(24):7264-7271.
Cancer Cell Proliferation in Vitro by Fruit and Berry Extracts and
Correlations with Antioxidant Levels.
Olsson ME, Gustavsson KE, Andersson S, Nilsson A, Duan RD.
Department of Crop Science, Swedish University of Agricultural Sciences,
P.O. Box 44, SE-230 53 Alnarp, Sweden; Department of Medicine, Lund
University Hospital, SE-221 85 Lund, Sweden; and Gastroenterology
Laboratory, Biomedical Center, B11, Lund
University, SE-221 84 Lund, Sweden.
The effects of 10 different
extracts of fruits and berries on cell
proliferation of colon cancer cells HT29 and breast cancer cells MCF-7 were
investigated. The fruits and berries used were rosehips, blueberries, black
currant, black chokeberries, apple, sea buckthorn, plum, lingonberries,
cherries, and raspberries. The extracts decreased the proliferation of both
colon cancer cells HT29 and breast cancer cells MCF-7, and the
concentration dependent. The inhibition effect for the highest concentration
of the extracts varied 2-3-fold among the species, and it was in the ranges
of 46-74% (average = 62%) for the HT29 cells and 24-68% (average = 52%) for
the MCF-7 cells. There were great differences in the content of the analyzed
antioxidants in the extracts. The level of the vitamin C content varied
almost 100-fold, and the content of total carotenoids varied almost 150-fold
among the species. Also in the composition and content of flavonols,
hydroxycinnamic acids, anthocyanins, and phenolics were found great
differences among the 10 species. The inhibition of cancer cell
proliferation seen in these experiments correlated with levels of some
carotenoids and with vitamin C levels, present at levels that can be found
in human tissues. The same inhibition of cell proliferation could not be
found by ascorbate standard alone. This correlation might indicate a
synergistic effect of vitamin C and other substances. In MCF-7 cells, the
anthocyanins may contribute to the inhibition of proliferation.
PMID: 15563205 [PubMed - as supplied by publisher]
J Agric Food Chem.
2003 Mar 12;51(6):1718-23.
Antiproliferative activity of apples is not due to phenolic-induced hydrogen
Liu RH, Sun J.
Department of Food Science and Institute of Comparative and Environmental
Toxicology, Cornell University, Ithaca, New York 14853-7201, USA. RL23@cornell.edu
Anticancer compound screening of natural products using tumor cell lines has
been commonly used to identify anticancer drugs. Two highly significant
anticancer drugs, paclitaxel (Taxol) and camptothecin, were discovered using
tumor cell lines by the U.S. National Cancer Institute (NCI) screening
program of plants. It has been recently reported that the inhibition of
cancer cell proliferation by fruit extracts was indirectly caused by
phenolic-induced H(2)O(2) 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 H(2)O(2)-induced oxidative
stress. The objective of the present study was to determine if
extracts induced H(2)O(2) formation in common cell culture media and to
investigate if the antiproliferative activity of
apple extracts was due to phenolic-induced H(2)O(2) formation. It is reported here that
did not induce H(2)O(2) formation in WME, DMEM, or DMEM/Ham F12 media with
the cell culture conditions tested. These same
proliferation of HepG(2) and Caco-2 cells. Therefore,
activity of apple extracts was not due to the phenolic-induced H(2)O(2)
production in cell culture media. In addition, H(2)O(2) added to the culture
medium at 100 microM did not cause inhibition of cell proliferation in
either HepG(2) liver cancer cells or Caco-2 colon cancer cells in vitro.