Do Not Throw Away Those Papaya Seeds, They Contain a Chemopreventive Natural Substance Called Benzyl Isothiocyanate


Isothiocyanates are sulphur-containing phytochemicals with the general formula R-NCS. Natural isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. 

Isothiocyanates are usually found in cruciferous or “cabbage family” vegetables such as:

  • bok choy
  • broccoli
  • broccoli sprouts
  • brussels sprouts
  • cabbage
  • cauliflower
  • Chinese cabbage
  • collards
  • horseradish
  • kale
  • kohlrabi
  • radish
  • rutabaga
  • turnips
  • wasabi
  • watercress

Isothiocyanates can also be found in the following foods:

  • capers
  • papaya seeds
  • nasturtiums

Scientists have identified 8 isothiocyanates that are found in the above listed foods and that have a beneficial effect on human health:

  • Allyl isothiocyanate (AITC)
  • Benzyl isothiocyanate (BITC)
  • Fluorescein isothiocyanate (FITC)
  • Methyl isothiocyanate (MITC)
  • Phenyl isothiocyanate (PITC)
  • Phenethyl isothiocyanate (PEITC)
  • Raphanin
  • Sulforaphane (SFN)

Benzyl isothiocyanate (BITC) is an isothiocyanate found in plants of the mustard family.  Benzyl isothiocyanate is found in the following foods:

  • Alliaria petiolata (Garlic mustard)
  • papaya seeds
  • pilu oil (an extract from seeds of the Pilu tree, the Meswak tree, and the Mustard tree)

Studies have indicted that higher intakes of BITC correlate with reduced risk of cancers.  1   BITC mechanism of actions against cancer can include not only ineterference with cancer cells’ energy utilization and causing them to die off before they can contribute to tumor growth, but also by inducing apoptosis and stimulate “signaling” molecules that tell cancer cells to die.

BITC also efficiently inhibits several cancer-promoting cytochrome enzymes, helping to prevent carcinogenesis.

BITC is also capable of inhibiting carcinogenesis from a diet containing polycyclic hydrocarbons like benzo[a]pyrene.  2

The table below illustrates how BITC can reduce the risk of various cancers:

Chemoprotection from Benzyl isothiocyanate (BITC)

Cancer TypeReference(s)
Bladder cancer1
Breast cancer2 3
Colon cancer4
Lung cancer5
Ovarian cancer6
Pancreatic cancer7

Image result for papaya seeds

Figure 1:  Papaya seeds

Papaya seeds contain a high level of BITC.  3  4  5  

In addition to the chemoprotection capabilities of papaya seeds through its high content of BITC, they also exhibits a promising source of antioxidants.  Papaya seeds protect fibroblasts from H2O2-induced stress.  6  7 

Papaya seeds also promote significant wound healing in rats and the authors of the study suggest further evaluation for this activity in humans.  8 

Informational References:

WikiHow – How to Eat Papaya Seeds


Herbal Papaya