More on Disease Prevention by Flavonoids
Luteolin is a bioflavonoid found in many of the same foods that contain
apigenin, including celery. While luteolin produces effects
similar to apigenin, it has its own unique beneficial properties
as well.
Like apigenin, luteolin inhibits the effects of epidermal growth
factor and tyrosine kinases, and therefore may have potential
as an anti-cancer and anti-metastasis agent. When measured against
27 citrus flavonoids, luteolin had the most potent antiproliferative
activities against several tumor and normal human cell lines.(95)
When compared to other flavonoids, only luteolin and quercetin
inhibited platelet activating factor and suppressed a type of inflammatory
response induced by allergens. The scientists who conducted the
study concluded that luteolin could be used to develop a novel type
of anti-inflammatory, anti-allergic drugs.(93)
Luteolin has been shown to arrest cancer growth at the G1 phase of the cell cycle
(96). Compared
to other flavonoids, luteolin more effectively inhibited proliferation
of human leukemia (CEM-C1 and CEM-C7) cells.(97)
Luteolin may help prevent breast and prostate cancer. It has
been shown to kill MCF-7 breast cancer cell cultures. Several studies show that luteolin reduces excess estrogen
formation by suppressing the aromatase enzyme and blocks the binding
of estrogens to breast cell receptor sites.
When a group of plant extracts were evaluated to ascertain if they
could maintain normal cell regulation, luteolin demonstrated the highest
anti-proliferative activity.(106)
Flavonoids are known to protect against radiation-induced free radical
damage. In a comparison study, luteolin was found to be the most
effective extract in reducing radiation damage to cells. The scientists
who conducted the study stated that these plant flavonoids show antioxidative potency in
vitro, work as antioxidants in vivo, and their radioprotective effects
may be attributed to their scavenging potency towards free radicals.(107)
How important are flavonoids in protecting against cancer? A human
epidemiological study showed a 56% reduction in stomach cancer in
those consuming the highest levels of flavonoids compared to the
lowest. The results of this study show that the well-established protective
effect of fruit and vegetables could, in part, be due to the presence
of flavonoids.(108)
When ranked in order of potency,
luteolin was more effective than vitamin C and seven other flavonoids
in reducing DNA oxidative damage.
Protecting against mitochondrial aging.
