CHLOROPHYLLS AS ANTICARCINOGENS (REVIEW)

Chlorophylls, chlorins, and other porphyrins have been used clinically for many years, including photodynamic therapy of tumors. More recent ly, the cancer chemopreventive properties of chlorophylls have come to be recognized. Chlorophylls exhibit anti-mutagenic activity in short- term genotoxicity assays, and protect against various intermediate bio markers of cancer in vivo. The anticarcinogenic activity of sodium-cop per chlorophyllin (CHL), a clinically-used water soluble salt of chlor ophyll, has been studied in several species. Collectively, the results from these studies support a chemopreventive role for CHL against aro matic carcinogens (aflatoxins, polycyclic aromatic hydrocarbons, heter ocyclic amines) in various target organs of rats, mice, and rainbow tr out. In vivo mechanism studies indicate that inhibition is most effect ive when CHL is administered simultaneously with the carcinogen, there by allowing direct interaction (molecular complex formation) between C HL and the carcinogen. Studies of post-initiation treatment with CHL h ave provided conflicting results, with evidence for inhibition or prom otion of carcinogenesis. These findings are discussed in terms of the inhibitory and promotional mechanisms of CHL, the relevance of such me chanisms to natural chlorophylls present in the diet, and the current use of CHL as a health supplement.