Inhibition of benzo[a]pyrene-DNA adduct formation by Aloe barbadensis Miller

Carcinogenesis. 1997 Apr;18(4):771-6. doi: 10.1093/carcin/18.4.771.


The antigenotoxic and chemopreventive effect of Aloe barbadensis Miller (polysaccharide fraction) on benzo[a]pyrene (B[a]P)-DNA adducts was investigated in vitro and in vivo. Aloe showed a time-course and dose-dependent inhibition of [3H]B[a]P-DNA adduct formation in primary rat hepatocytes (1x10(6) cells/ml) treated with [3H]B[a]P (4 nmol/ml). At concentrations of 0.4-250 microg/ml aloe, the binding of [3H]B[a]P metabolites to rat hepatocyte DNA was inhibited by 9.1-47.9%. Also, in rat hepatocytes cultured for 3-48 h with aloe (250 microg/ml) and [3H]B[a]P (4 nmol/ml), [3H]B[a]P-DNA adducts were significantly reduced by 36% compared with [3H]B[a]P alone. Aloe also inhibited cellular uptake of [3H]B[a]P in a dose-dependent manner at a concentration of 0.4-250 microg/ml by 6.3-34.1%. After a single oral administration of B[a]P to male ICR mice (10 mg/mouse), benzo[a]pyrene diol epoxide I (BPDE-I)-DNA adduct formation and persistence for 16 days following daily treatment with aloe (50 mg/mouse) were quantitated by enzyme-linked immunosorbent assay using monoclonal antibody 8E11. In this animal model, BPDE-I-DNA adduct formation was significantly inhibited in various organs (liver, kidney, forestomach and lung) (P < 0.001). When mice were pretreated with aloe for 16 days before B[a]P treatment, inhibition of BPDE-I-DNA adduct formation and persistence was enhanced. Glutathione S-transferase activity was slightly increased in the liver but cytochrome P450 content was not affected by aloe. These results suggest that the inhibitory effect of aloe on BPDE-I-DNA adduct formation might have a chemopreventive effect by inhibition of B[a]P absorption.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aloe / chemistry*
  • Animals
  • Benzo(a)pyrene / antagonists & inhibitors*
  • Benzo(a)pyrene / metabolism
  • Cells, Cultured
  • Chemoprevention
  • Chromatography, High Pressure Liquid
  • Cytochrome P-450 Enzyme System / metabolism
  • DNA Adducts / antagonists & inhibitors*
  • DNA Adducts / metabolism
  • Glutathione Transferase / metabolism
  • Liver / drug effects*
  • Liver / enzymology
  • Liver / metabolism
  • Male
  • Mice
  • Mice, Inbred ICR
  • Plant Extracts / pharmacology*
  • Plants, Medicinal*
  • Rats
  • Rats, Sprague-Dawley
  • Subcellular Fractions / metabolism
  • Tritium


  • DNA Adducts
  • Plant Extracts
  • benzo(a)pyrene-DNA adduct
  • Tritium
  • Benzo(a)pyrene
  • Cytochrome P-450 Enzyme System
  • Glutathione Transferase