Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons

Environ Toxicol Pharmacol. 2015 Nov;40(3):758-63. doi: 10.1016/j.etap.2015.09.005. Epub 2015 Sep 12.


DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (p<0.1) and a positive association between chlorella-induced changes in global hypermethylation and urinary 1-OHP (p<0.01). Therefore, our study suggests chlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.

Keywords: Chlorella; Clinical trial; Epigenetic; Global methylation; Polycyclic aromatic hydrocarbons.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Chlorella vulgaris / chemistry*
  • Cross-Over Studies
  • DNA / drug effects*
  • DNA Methylation / drug effects
  • Dietary Supplements
  • Double-Blind Method
  • Epigenesis, Genetic / drug effects*
  • Female
  • Humans
  • Polycyclic Aromatic Hydrocarbons / administration & dosage
  • Polycyclic Aromatic Hydrocarbons / toxicity*
  • Pyrenes / urine
  • Random Allocation
  • Tablets
  • Young Adult


  • Polycyclic Aromatic Hydrocarbons
  • Pyrenes
  • Tablets
  • DNA
  • 1-hydroxypyrene