Assay to reveal health role of compounds.

A new in-vitro screening assay is under development that will detect the preventive or inhibitory health effects of food components. Investigators are in the last year of their effort to determine the role that various components play in initiating colorectal cancer. The screening assay is based on the ability to detect the genomic changes--multi-gene expression and changes in protein concentrations--involved in colorectal carcinogenesis.

The scientists are identifying the genes involved in the process of colorectal cancer in both human and rat models. They are using several carcinogenic and anticarcinogenic agents in their studies. Among the latter is the flavonoid resveratrol. Researchers also are mapping the proteins expressed in healthy and tumor tissue as well as in cancer cell lines.

The model compound used, resveratrol, is a component that research has determined may be a very potent inhibitor of human colon cancer cell growth in vitro. After prolonged exposure to many cancer cell lines, an increased necrosis of these cells occurs when this compound is in the system. Experiments are continuing, and additional results should be reported later this year.

Resveratrol is touted by nutritionists and biochemists because of its potential as an anticancer and cardioprotective compound. Resveratrol belongs to the phytoalexin class of phytochemicals and functions as a moderate antioxidant, quenching free radical damage linked to several cancers. The compound has also demonstrated anti-inflammatory properties that help it to block reactions associated with the cancer process.

In humans, studies have been underway worldwide to determine health benefits of resveratrol in cancer and heart disease. Preliminary research demonstrates that resveratrol may have anti-infective, antioxidant and anti-inflammatory properties. Studies involving cancer-prone mice suggest that resveratrol seems to reduce the occurrence of skin tumors. Additional studies suggest that resveratrol is unique because of its ability to battle cancer at all three steps of the cancer process: initiation, promotion and progression. Researchers believe that resveratrol is partially responsible for the cholesterol-lowering effects of red wine.

Epidemiologic and clinical studies indicate that high consumption of resveratrol-rich foods may result in reduced cardiovascular disease risk, lowered total cholesterol and lowered LDL cholesterol. Resveratrol's antioxidant properties may again be the mechanism at work in reducing the oxidation of LDL cholesterol.

Further information. Ruud Woutersen, TNO Voeding, Utrechtseweg 48, Postbus 360, 3700 AJ Zeist, The Netherlands; phone: [phone]; fax: [phone]; email: [e-mail].