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frambozen en ander fruit tegen leukemie.*
is nu bekend hoe de bioactieve stoffen, anthocyanen kankercellen kunnen doden.
Normaal gebruikte therapieŽn zoals chemo en bestraling doden niet alleen
kankercellen doch ook gezonde cellen. De celtesten werden uitgevoerd met een
natuurlijke vorm van het anthocyaan te weten cyanidine-3-rutinoside (C-3-R) en
leukemiecellen. De kankercellen reageerde op C-3-R door peroxiden te produceren
waardoor de kankercellen dood gingen. Gezonde cellen produceerden geen peroxiden
als ze met C-3-R in contact kwamen. Bij een lage dosis C-3-R was de helft van de
leukemiecellen in 18 uur dood. Bij een dubbele dosis waren in dezelfde tijd alle
kankercellen dood. De anthocyaan C-3-R zit in allerlei fruit waaronder zwarte
frambozen, kersen, druiven en andere bessen. Bij de testen werd een extract
C-3-R van zwarte frambozen gebruikt.
Found In Many Foods And Red Wine Is Potent And Selective Killer Of Leukemia
naturally occurring compound found in many fruits and vegetables as well as red
wine, selectively kills leukemia cells in culture while showing no discernible
toxicity against healthy cells, according to a study by researchers at the
University of Pittsburgh School of Medicine. These findings, which were
published online in the Journal of Biological Chemistry, offer hope for a
more selective, less toxic therapy for leukemia.
"Current treatments for leukemia, such as chemotherapy and radiation, often damage healthy cells and tissues and can produce unwanted side effects for many years afterward. So, there is an intensive search for more targeted therapies for leukemia worldwide," said corresponding author Xiao-Ming Yin, M.D., Ph.D., associate professor of pathology, University of Pittsburgh School of Medicine.
Leukemia is not a single disease but a number of related cancers that start in the blood-forming cells of the bone marrow. Meaning literally 'white blood' in Greek, leukemia occurs when there is an excess of abnormal white blood cells. There are both acute and chronic forms of leukemia, each with many subtypes that vary in their response to treatment. According to the National Cancer Institute, about 44,000 new leukemia cases will be diagnosed in the United States in 2007, and there will be about 22,000 leukemia-related deaths.
Based on previous reports that anthocyanidins, a group of naturally occurring compounds widely available in fruits and vegetables as well as red wine, have chemopreventive properties, Dr. Yin and his collaborators studied the effects and the mechanisms of the most common type of a naturally modified anthocyanidin, known as cyanidin-3-rutinoside, or C-3-R, which was extracted and purified from black raspberries, in several leukemia and lymphoma cell lines.
They found that C-3-R caused about 50 percent of a human leukemia cell line known as HL-60 to undergo programmed cell death, or apoptosis, within about 18 hours of treatment at low doses. When they more than doubled the concentration of C-3-R, virtually all of the leukemia cells became apoptotic and died. C-3-R also induced apoptosis in other human leukemia and lymphoma cell lines.
When the investigators studied the mechanism of cell death in the leukemia cells, they found that C-3-R induced the accumulation of peroxides, a highly reactive form of oxygen, which, in turn, activated a mitochondria-mediated apoptotic pathway. Mitochondria are specialized structures located within all cells in the body that contain enzymes needed by the cell to metabolize foodstuffs into energy sources. In contrast, when the researchers treated normal human blood cells with C-3-R, they did not find any increased accumulation of reactive oxygen species and there were no apparent toxic effects on these cells.
Previous studies have shown that C-3-R possesses strong antioxidant activities, a characteristic shared by other polyphenols, such as those found in green tea, which could be responsible for their chemoprevention effects. Dr. Yin's work suggests that although C-3-R demonstrates antioxidant effects in the normal cells, it paradoxically induces an oxidative 'stress' in the tumor cells. It is possible that this differential effect of C-3-R may account for its selective toxicity in the tumor cells.
According to Dr. Yin, these results indicate that C-3-R has the promising potential to be used in leukemia therapy with the advantages of being highly selective against cancer cells. "Because this compound is widely available in foods, it is very likely that it is not toxic even in purified form. Therefore, if we can reproduce these anti-cancer effects in animal studies, this will present a very promising approach for treating a variety of human leukemias and, perhaps, lymphomas as well."
CONTACT: Clare Collins
In addition to Dr. Yin, others involved in the study included Rentian Feng, Ph.D., Hong-Min Ni, M.D., Irina L. Tourkova, Ph.D., and Michael R. Shurin, M.D., all of the department of pathology, University of Pittsburgh School of Medicine; Shiow Y. Wang, Ph.D., of The Fruit Laboratory, Beltsville Agricultural Research Center, U.S. Department of Agriculture; and Hisashi Harada, Ph.D., of the department of internal medicine, Virginia Commonwealth University. (Mei 2007) (Opm. Dit zijn nog maar celtesten doch het versterkt wederom de kracht van gezonde voeding met veel bioactieve stoffen zoals anthocyanen.)