Query: chlorophyll

Relevant passages:
Antimutagens and anticarcinogens: a survey of putative interceptor molecules. <=SEP=> In this review recent publications are cited for a number of antimutagens. The molecules surveyed are potential or proven "desmutagens" or "interceptors." These are biologically prevalent or synthetic molecules that are most often small metabolites proficient in binding to, or reacting with, mutagenic chemicals and free radicals. Many of this class of "blocking agents" are "soft" and "hard" nucleophiles with consequently varying abilities to react with particular classes of electrophiles, the major classes of direct-acting mutagens. Although they serve as a first line of defense against mutagens and carcinogens, many interceptor molecules are under-investigated with regard to their spectra of activity and their possible relevance to prophylaxis or treatment of human disease states.

Effects of chlorophyll and chlorophyllin on low-dose aflatoxin B(1) pharmacokinetics in human volunteers. <=SEP=> Chlorophyll (Chla) and chlorophyllin (CHL) were shown previously to reduce carcinogen bioavailability, biomarker damage, and tumorigenicity in trout and rats. These findings were partially extended to humans, where CHL reduced excretion of aflatoxin B(1) (AFB(1))-DNA repair products in Chinese unavoidably exposed to dietary AFB(1). However, neither AFB(1) pharmacokinetics nor Chla effects were examined. We conducted an unblinded crossover study to establish AFB(1) pharmacokinetic parameters among four human volunteers, and to explore possible effects of CHL or Chla cotreatment in three of those volunteers. For protocol 1, fasted subjects received an Institutional Review Board-approved dose of 14C-AFB(1) (30 ng, 5 nCi) by capsule with 100 mL water, followed by normal eating and drinking after 2 hours. Blood and cumulative urine samples were collected over 72 hours, and 14C- AFB(1) equivalents were determined by accelerator mass spectrometry. Protocols 2 and 3 were similar except capsules also contained 150 mg of purified Chla or CHL, respectively. Protocols were repeated thrice for each volunteer. The study revealed rapid human AFB(1) uptake (plasma k(a), 5.05 + or - 1.10 h(-1); T(max), 1.0 hour) and urinary elimination (95% complete by 24 hours) kinetics. Chla and CHL treatment each significantly impeded AFB(1) absorption and reduced Cmax and AUCs (plasma and urine) in one or more subjects. These initial results provide AFB(1) pharmacokinetic parameters previously unavailable for humans, and suggest that Chla or CHL co-consumption may limit the bioavailability of ingested aflatoxin in humans, as they do in animal models.

Molecular pathways for cancer chemoprevention by dietary phytochemicals. <=SEP=> Interest in dietary phytochemicals for potential cancer chemoprevention has increased substantially. Screening dietary compounds for chemopreventive activity however, requires a systematic and wide-ranging approach to encompass the complexity of carcinogenesis. We present some of the molecular pathways that underpin the broad biological processes involved in carcinogenesis. Oxidative stress, inflammation, and the evasion of apoptosis are important biological mechanisms by which carcinogenesis occurs. Subsequently, antioxidant, anti-inflammatory, and pro-apoptotic activity represent important activities for preventing, suppressing, or reversing the development of carcinogenesis. Ultimately, these mechanisms of action may provide a useful basis for screening novel phytochemicals for chemopreventive activity. In this review, we identify the important molecular processes that may be targeted in routine screenings of dietary phytochemicals to ultimately select the most effective potential candidates for cancer chemoprevention.

Natural compounds in the human diet and their ability to bind mutagens prevents DNA-mutagen intercalation. <=SEP=> Human diet may contain many mutagenic or carcinogenic aromatic compounds as well as some beneficial physiologically active dietary components, especially plant food phytochemicals, which act as mutagenesis or carcinogenesis inhibitors. This study compared the binding properties of natural compounds in the human diet (caffeine, theophylline, theobromine, and resveratrol) with a water-soluble derivative of chlorophyll to bind to acridine orange, a known mutagen. An analysis was conducted to determine which substances were effective binding agents and may thus be useful in prevention of chemical-induced mutagenesis and carcinogenesis. Data indicated that in order to bind 50% of the mutagen in a complex, less than twice the concentration of chlorophyllin was needed, the resveratrol concentration was 20-fold higher, while a 1000-fold or even 10,000-fold excess of xanthines were required to bind acridine orange.