Eight Important Dietary Phytochemical Compounds That Have Chemopreventive Effects

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There are three established and accepted stages to carcinogenesis:

  • initiation
  • promotion, and
  • progression

The purpose of chemoprevention is to disrupt or delay the multiple pathways and processes of these three stages.

One method of chemoprevention is the use of dietary phytochemical blocking agents.  Blocking agents are biomolecules that inhibit the initiation stage of carcinogenesis.  DNA is irreparably damaged during the initiation stage of carcinogenesis and blocking agents effectively prevent DNA mutations by inactivating or metabolizing carcinogens directly.  This is triggered by inducing antioxidant enzyme activity as free radical scavengers and initiating mechanisms of DNA repair. 1  

These blocking agents inhibit the conversion of procarcinogens to DNA damaged cells through the following mechanisms: 2  

  • Antioxidant activity
  • Blockade of carcinogen uptake
  • Induction of phase II drug-metabolising enzymes
  • Induction of DNA repair
  • Inhibition of phase I drug-metabolising enzymes
  • Scavenging of free radicals

Certain dietary phytochemical compounds have been studied for their ability to block the initiation phase of carcinogenesis.  The various research papers demonstrated that these dietary phytochemical compounds up regulates and increases NF-E2-related factor 2 (Nrf2) expression.   Nrf2 is a powerful protein that is latent within each cell in the body, unable to move or operate until it is released by an Nrf2 activator. Once released it migrates into the cell nucleus and bonds to the DNA at the location of the Antioxidant Response Element (ARE) or also called hARE (Human Antioxidant Response Element) which is the master regulator of the total antioxidant system that is available in all human cells. 3 

Eight dietary phytochemical compounds have been identified for their ability to reduce the potential for carcinogenesis initiation by acting as blocking agents that prevent DNA mutations.  The Table below lists these 8 dietary phytochemical compounds: 4

Eight dietary phytochemical compounds and their chemopreventive effects

Chemical CompoundFoods/Herbs/SpicesChemopreventive Effects
2-methoxystypandronePolygonum cuspidatum or Fallopia japonica (Japanese knotweed)Inhibits JAK and IKKβ kinase signaling to NF-κB
ApigeninParsley (dried); Chamomile (Matricaria chamomilla) Inhibits NF-κB DNA binding, IκB-α phosphorylation, and IKKβ activity
CurcuminTurmeric (curcuma longa)Up regulates Nrf2 signaling; Induces apoptosis; Inhibits NF-κB signaling; decreases cell invasion and motility
Epigallocatechin gallate (EGCG)Green tea (camillia sinensis); White teaInhibits proteasome activity for IκBα stabilization and NFkB inhibiton; Increases expression of E-cadherin; Inhibitis signal transduction through ERK
[6]-gingerolZingiber officinale; ginger rootIncreases expression of E-cadherin; Inhibits signal transduction through ERK; Inhibits MMP-9 expression
Isothiocyanate/SulforaphaneBrussels sprouts, cabbage, cauliflower, bok choy, kale, collards, broccoli raab, broccoli sprouts, kohlrabi, mustard, turnip, radish, arugula, and watercressIncreases Nrf2 expression
LuteolinTerminalia chebula (Triphala); celery, broccoli, green pepper, parsley, thyme, dandelion, perilla, chamomile tea, carrots, olive oil, peppermint, rosemary, navel oranges, and oreganoInhibits MMP-9 expression
ResveratrolSkin of red grapes; Polygonum cuspidatum or Fallopia japonica (Japanese knotweed)Increases expression of E-cadherin; Inhibits signal transduction through PI3K/Akt

Images of Foods, Herbs and Spices that contain the 8 Dietary Phytochemical Compounds

  • Japanese knotweed (2-methoxystypandrone)