Polyphenols anti-tumor activity

Polyphenols, such as curcumin, quercetin and resveratrol, are some examples of naturally occurring phytochemicals with proven antioxidant and anti-inflammatory activity, beneficial cardiovascular effects," antiatherosclerotic effects, chemopreventive, and anticarcinogenic effects. An abundance of mechanistic information has become available on how polyphenols derived from dietary sources, which have putative chemopreventive properties, interfere with tumor promotion and progression. The effect of these bioactive compounds on the organism is influenced by their bioavailability, namely, their ability to be effectively absorbed by the human body. However, the polyphenols have a poor bioavailability and are rapidly metabolized by human body, losing their potential beneficial effects. ... 

Ito H, Miyake M, Nishitani E, Mori K, Hatano T, Okuda T, Konoshima T, Takasaki M, Kozuka M, Mukainaka T, Tokuda H, Nishino H, Yoshida T (1999) Anti-tumor promoting activity of polyphenols from Cowania mexicana and Coleogyne ramosissirm. Cancer Lett 143 5-13... 

Zhao, J, Wang, J, Chen, Y and Agarwal, R (1999) Anti-tumor-promoting activity of a polyphenolic fraction isolated from grape seeds in the mouse skin two-stage initiation-promotion protocol and identification of procyanidin B5-3 -gaUate as the most effective antioxidant constituent. Carcinogenesis, 20, 1737-1745. 

Like many other antioxidants, rosemary and its polyphenols possess not only antioxidative activities, but also antitumorigenic activities. Huang et al. (5) investigated the inhibitory effects of rosemary extract, carnosol and ursolic acid on tumor formation in mouse skin. They found that topical application of rosemary inhibits B(a)P- and DMBA-induced initiation of tumor and TPA-induced tumor promotion in DMBA-initiated mice. Carnosol and ursolic acid were found to be strong inhibitors of TPA-induced inflammation, ornithine decarboxylase activity and tumor promotion in mouse skin (5). It was suggested that carnosol acted like other nonsteroidal phenolic anti-inflammatory agents, such as curcumin, which inhibited the metabolism of arachidonic acid. 

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