Chemopreventive properties of chlorophyllin: inhibition of aflatoxin B1 (AFB1)-DNA binding in vivo and anti-mutagenic activity against AFB1 and two heterocyclic amines in the Salmonella mutagenicity assay

Carcinogenesis. 1991 May;12(5):939-42. doi: 10.1093/carcin/12.5.939.


Chlorophyllin (CHL), a sodium/copper derivative of chlorophyll, has been used to treat a number of human conditions with no toxic effects being reported. Recent studies have described the anti-mutagenic activity of CHL in several short-term genotoxicity assays; however, this compound has not been reported to inhibit carcinogen--DNA binding in vivo, and it has yet to be evaluated as an anti-carcinogen in any species. The chemopreventive properties of CHL were studied in trout using inhibition of aflatoxin B1 (AFB1)--DNA binding as an end-point. Chlorophyllin and AFB1 were coadministered in the diet, and carcinogen--DNA binding levels were determined in liver after 1, 3, 5 and 7 days. Linear increases in AFB1--DNA binding occurred with time of treatment at each CHL dose level (0, 500, 1000 and 2000 p.p.m.). Each increase in CHL dose produced a concomitant decrease in AFB1--DNA binding, resulting in a series of curves of decreasing slope. At the highest CHL dose level of 2000 p.p.m., AFB1--DNA binding was inhibited by 70%. These results suggest that CHL should be a potent inhibitor of AFB1-induced hepatocarcinogenesis in this model. In the Salmonella assay, CHL exhibited potent anti-mutagenic activity against AFB1 and two heterocyclic amines when incubated in the presence of trout liver activation systems. CHL also inhibited the mutagenic activity of AFB1-8,9-epoxide in the absence of a metabolic activation system. Dietary CHL substantially inhibited liver AFB1-DNA binding in vivo, even when AFB1 was given by i.p. injection to avoid direct AFB1--CHL interaction in the diet or gut. Collectively, these studies support a CHL inhibitory mechanism involving complex formation with the carcinogen in the gut coupled with electrophile scavenging or further complexing in the target organ.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aflatoxin B1
  • Aflatoxins / antagonists & inhibitors
  • Aflatoxins / metabolism*
  • Animals
  • Carbolines / toxicity*
  • Chlorophyllides / pharmacology*
  • DNA / metabolism*
  • Mutagenicity Tests
  • Mutagens / antagonists & inhibitors*
  • Quinolines / toxicity*
  • Salmonella typhimurium / genetics*
  • Trout


  • Aflatoxins
  • Carbolines
  • Chlorophyllides
  • Mutagens
  • Quinolines
  • 2-amino-3-methylimidazo(4,5-f)quinoline
  • 3-amino-1-methyl-5H-pyrido(4,3-b)indole
  • DNA
  • Aflatoxin B1
  • chlorophyllin