POLYPHENOL ANTIOXIDANTS IN GREEN TEA AND OATS: POTENTIAL ROLES IN ANGIOGENESIS AND
ATHEROSCLEROSIS
Mohsen Meydani, Liping Liu, Shaun Rodriguez
Vascular Biology Laboratory, Jean Mayer USDA-Human Nutrition Research
Center on Aging at Tufts University, Boston, MA.
Cancer and cardiovascular diseases (CVD) are the major causes of
morbidity and mortality among middle aged and older people in Western
societies. Epidemiological and experimental evidence indicate that
dietary habits play important roles in the risk of these diseases.
Polyphenols with antioxidant capacity have recently been recognized for
their potential health effects. Green tea contains catechins and oats
are unique for their avenanthramides content; both are polyphenolics
with powerful antioxidant capacity. Consumption of green tea, which is
associated with a reduced risk of certain forms of cancer, can inhibit
carcinogenesis and tumor growth and metastasis by suppressing
angiogenesis. We have recently elucidated the molecular mechanism by
which epigallocatechin gallate (EGCG), one of the green tea catechins,
inhibits angiogenesis. EGCG inhibited tyrosine phosphorylation of
vascular endothelial (VE)-cadherin in vascular endothelial cell growth
factor (VEGF)-induced tube formation. In addition, EGCG inhibited the
signaling pathway involving VEGFR, PI3-kinase, ?-catenin, and
VE-cadherin complex. We have recently discovered that oats, in addition
to their health benefits for CVD through their soluble fiber content,
have potential anti-inflammatory and antiatherogenic properties due to
their avenanthramides content. We have found that avenanthramides
reduced expression of adhesion molecules such as ICAM-1, VCAM-1, and
E-selectin, inhibited adhesion of monocytes to endothelial cells, and
reduced expression of proinflammatory cytokines such as IL-6, IL-8, and
MCP-1. Thus, inclusion of green tea and oats in the daily diet during a
lifespan may reduce the risk of cancer and CVD, the two major
age-related diseases. Supported by NCI grant# 1 R03CA94290-01 and USDA
contract# 58-1950-9-001.
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