
Ellagic acid is a naturally occurring phenolic constituent in
certain fruits and nuts. Research in the past decade confirms that
Ellagic acid
markedly inhibits the ability of other chemicals to cause mutations
in bacteria.
Ellagic acid
from red raspberries has proven as an effective antimutagen and
anticarcinogen as well as a inhibitor of cancer.
Ellagic acid has been found to occur naturally in 46
different foods, with the red raspberry
having been identified as having the highest
natural content.
Ellagic acid is a phenolic compound found in plants in the form of
hydrolyzable tannins called ellagitannins. Ellagitannins are esters of
glucose with hexahydroxydiphenic acid; when hydrolyzed, they yield Ellagic acid, the dilactone of
hexahydroxydiphenic acid. Ellagic acid is a
very stable compound and is readily absorbed through the gastrointestinal
system in mammals, including humans.
Research studies on Ellagic acid have been extensive, especially
in vitro studies and studies in laboratory animals. Although yet to prove
conclusively in humans that red raspberries will reduce risk of cancer or
even cause remission of active disease, this research does represent a
substantial body of evidence to support the protective effects of
ellagitannins in humans in combination with other chemopreventive
nutrients.
Berries are the most common
food sources of Ellagic acid. The relative
amount of Ellagic acid in average number of
micrograms per gram of dry weight fruit extract is highest in red
raspberries at 1500 mcg, followed by strawberries at 630 mcg, walnuts at
590 mcg, pecans at 330 mcg, and cranberries at 120 mcg.
Torre, et al.,
performed a quantitative evaluation of red raspberries that was published
in the Journal of Food Sciences in 1977:
Ellagic acid promotes carcinogen detoxification by stimulating the
activity of various isoforms of the enzyme glutathione-S- transferase in
hepatoma (liver cancer).
Ellagic acid slows the growth of abnormal colon cells in humans,
prevents the development of cells infected with the human papilloma virus
(HPV) linked to cervical cancer, and triggers apoptosis (natural death) of
prostate cancer cells. This apoptotic process may also have beneficial
effects on breast, lung, esophageal, and skin cancer (melanoma).
Ellagic acid from raspberries causes apoptosis (normal cell death)
of human cervical cancer cells (human papilloma virus), induces G1
inhibition of cancer cell division, and prevents destruction of the P53
gene by cancer cells. P53 is regarded as a safeguard against mutagenic
activity (cancer causing changes) in cervical cells (Nixon, Narayanan).
Unpublished research at the
Hollings Cancer Center shows that one cup of raspberries per week will
stop prostate cancer growth for a period of up to one week. Their studies
reveal that Ellagic acid from red raspberries
is readily absorbed through the gastrointestinal tract. Ellagic acid retains its potency after
heating, freezing and concentration processing. So whether consumed fresh,
in juices, fruit spreads, preserves or sorbets, red raspberry has been
recommended as a beneficial part of any healthy diet.
Inhibition of carcinogenesis
by Ellagic acid has been demonstrated in
animals with esophagus, tongue, lung, colon, liver, and skin tumors. Ellagic acid inhibits the initiation of
tumors through a number of mechanisms, including inhibition of metabolic
activation of carcinogenic compounds (such as polycyclic hydrocarbons,
nitroso-containing chemicals or food preservatives, and aflatoxins) into
forms that induce cell DNA damage.
Ellagic acid acts as a scavenger to "bind" cancer-causing
chemicals, making them inactive. It inhibits the ability of other
chemicals to cause mutations in bacteria. In addition, Ellagic acid from red raspberries prevents
binding of carcinogens to DNA, and reduces the incidence of cancer in
cultured human cells exposed to carcinogens. Ellagic
acid has been shown to inhibit chemically induced cancer in the
lung, liver, skin and esophagus of rodents, and TPA-induced tumor
promotion in mouse skin (Stoner).
Ellagic acid elicits a dose-dependent bactericidal effect in H.
pylori cultures, the bacteria thought primarily responsible for the
development of gastric ulcers (Chung).
Ellagic acid is an effective inhibitor of lung and esophageal
tumors in mice (Stoner).
Ellagic acid inhibits lipid peroxide and liver hydroxy proline and
rectifies liver pathology in laboratory animal hepatotoxcity induced by
carbon tetrachloride (Thresiamma).
Cancer can affect DNA by
covalent bonding of the carcinogen to the DNA molecule. Ellagic acid inhibits mutagenesis and
carcinogenesis by forming adducts with DNA, thus masking binding sites to
be occupied by the mutagen or carcinogen (Teel).
Ellagic acid treatment of preweanling mice before an injection of
B(a)P diol-epoxide caused a 44-75% inhibition in the number of
diol-epoxide-induced lung tumors (Chang).
Ellagic acid inhibits N-nitrosomethylbenzylamine (NMBA)
tumorigenesis in the esophagus of F-344 rats.
Ellagic acid inhibited the development of both preneoplastic and
neoplastic lesions by 25-50% (Daniel and Stoner).
Ellagic acid reduced the number of altered foci and the incidence
of hepatocellular neoplasms in rats with liver cancer induced by
N-2-fluorenylacetamide (Tanaka).
There is clinical evidence
that Ellagic acid may inhibit tumors of the
prostate and cervix. Preliminary studies in volunteers indicate Ellagic acid shows up in cervical tissue
after oral ingestion of red raspberries. One study will evaluate women
with atypical squamous cells of undetermined significance (ASCUS) in which
there is neither treatment nor clinical evaluation available. ASCUS
represents as much as 10% of all Papanicolaou smears in the US and
represents approximately 5 million females. In this population, women
infected with human papillomaviruses (HPV) types 16 and/or 18 are at the
greatest risk of developing cervical cancer at some stage in their lives.
This population represents approximately one million women in the United
States alone, and in India is one of the two major cancers affecting
women.
Ellagic acids do more than prevent cancer. Berries may also help
prevent heart attacks because they contain a natural form of aspirin
called salicylates. British researchers analyzed the blood of subjects who
were not taking any form of aspirin or drugs containing salicylates. They
found salicylic acid and two related compounds present in blood,
presumably from dietary sources, including raspberries and blackberries.
Researchers at the National
Center for Health Statistics (NCHS) in Hyattsville, Maryland established a
connection between reduced risk of heart attack and increased intake of
salicylates. They found that during a 10 year period beginning in 1960,
when heart attack rates began to decline, non-aspirin salicylate
consumption went up due to salicylate in processed foods which used a
synthetic version to add flavor and aroma.
Ellagic acid is pharmacologically active and has been found to control
hemorrhage in animals and in humans, presumably as a result of its ability
to activate Hageman factor. Animal tests suggest that red raspberry may
reduce levels of glucose (blood sugar) in animals, and therefore may help in
the management of diabetes.
Ellagic acid inhibits lipid peroxidation necrosis of skin flaps,
enhancing preservation of grafting procedures (Ashoori).
Ellagic acid has a marked inhibitory effect on acid secretion and
the occurrence of stress-induced gastric lesions (Murakami).
Ellagitannins are also
believed by herbalists to be effective in treating diarrhea, nausea,
vomiting and morning sickness in pregnancy. Herbalists do not, however,
recommend you use red raspberry for this purpose at home even though red
raspberry leaves are included in several herbal pregnancy formulas sold in
the United States for women with a history of miscarriage or difficult
pregnancy for the purpose of regulating uterine contractions, morning
sickness, hot flashes, diarrhea (use weak tea for infants), and for
reducing excessive menstrual flow. The herb is also used as a gargle for
sore throats.
Consuming one cup (150
grams) of red raspberries per day prevents the development of prostate
cancer cells in unpublished studies. Most extract formulas recommend from
500-2000 mg of ellagitannins per day. The amount of
Ellagic acid found in red raspberries is 1500 micrograms per gram
of dry weight. If one cup contains 150 grams by dry weight, then each cup
of red raspberries would average 225 mg of Ellagic
acids as well as up to 90 mg of anthocyanidins and less than 40 mg
of other polyphenols including flavanols. As with many herbal remedies,
suggested use and precise dose response relationships have not been
established for ellagitannins extracted from red raspberries.
Selected
References
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