Curcumin and other polyphenolic compounds in head and neck cancer chemoprevention

Abstract

Despite clear results of observational studies linking a diet rich in fruits and vegetables to a decreased cancer risk, large interventional trials evaluating the impact of dietary micronutrient supplementation, mostly vitamins, could not show any beneficial effects. Today it has become clear that a single micronutrient, given in supernutritional doses, cannot match cancer preventive effects of whole fruits and vegetables. In this regard polyphenols came into focus, not only because of their antioxidant potential but also because of their ability to interact with molecular targets within the cells. Because polyphenols occur in many foods and beverages in high concentration and evidence for their anticancer activity is best for tissues they can come into direct contact with, field cancerization predestines upper aerodigestive tract epithelium for cancer chemoprevention by polyphenols. In this paper, we summarize cancer chemopreventive attempts with emphasis on head and neck carcinogenesis and discuss some methodological issues. We present data regarding antimutagenic effects of curcumin and epigallocatechin-3-gallate in human oropharyngeal mucosa cultures exposed to cigarette smoke condensate.

Figure 1

DNA damage (% tail DNA) caused by cigarette smoke condensate (CSC), after previous incubation with Curcumin on 1 day or on 4 days (n = 20; o = outlier value, * = extreme value; α-level = 0.02).

Figure 2

DNA damage (% tail DNA) caused by cigarette smoke condensate (CSC), after previous incubation with curcumin, epigallocatechin-3-gallate (EGCG), or both, on 1 day or on 4 days (n = 20; o = outlier value; α-level = 0.006).