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Biological
effects of EGCG
Epigallocatechin
gallate (EGCG) is a potent antioxidant polyphenols of green tea, is
associated with antioxidant, antitumor and antimutagenic activities.
The antioxidant activity is at last 100 more times more effective than
vitamin C and 25 times more effective than vitamin E at protecting cells
and DNA from damage which are believed to be linked to cancer, heart
disease and other potentially fatal illnesses. The biological benefits
of EGCG are generally attributed to their antioxidant activity to scavenge
free radical oxygen.
EGCG is
the major component of the polyphenolic fraction of green tea. It make
up about 10-50% of the total green tea catechins includeing epigallocatechin
gallate (EGCG), epigallocatechin (EGC), epicatechin gallate(ECG), epicatechin(EC),
gallocatechin gallate (GCG), catechin are major catechin of green tea
catechin. The antioxidant activity increased in the following order:
EC
Many studies
indicate EGCG play a role as,protect aganist free-radical DNA damage;protect
aganist the effects of ionizing radiation and ultraviolet radiation;inhibit
lipid peroxidation, decrease serum cholesterol levels, LDL, VLDL and
triglycerides;interfere with the binding of cancer-causing agents to
cellular DNA, help to neutralize dietary carcinogens;work with enzymes
and other antioxidants in the intestine, liver and lungs to prevent
the activation of certain carcinogens before they damage DNA;as a free
radicals scavenger, combat the effects of pollution, sunlight and smoking,
help skin from wrinkling and aging.
Pepper
increases EGCG availability
An animal
study suggests that consuming the spice, black pepper, when drinking
green tea can significantly increase the amount of epigallocatechin-3-gallate
(EGCG) absorbed. In this study, rats and mice given green tea along
with piperine (a bioactive component in black pepper) absorbed 130%
more EGCG than control animals receiving EGCG alone.
In this
study, piperine was found to inhibit the glucuronidation of EGCG in
the intestines. Glucuronidation is a chemical pathway that serves as
one of the major ways our bodies convert drugs, steroids, and many other
substances into metabolites that can then be excreted into the urine
or bile. By inhibiting EGCG's glucuronidation, piperine allowed more
of this catechin to be absorbed and utilized. So, next time you have
a cup of green tea along with a meal, be sure to spice up your soup,
salad and/or entrée with a little freshly ground black pepper.
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