Cancer chemopreventive effects of the flavonoid-rich fraction isolated from papaya seeds

Nutr Cancer. 2014;66(5):857-71. doi: 10.1080/01635581.2014.904912. Epub 2014 May 12.


Intervention to decelerate, arrest, or reverse the process of carcinogenesis by the use of either natural or synthetic agents individually or in combination has emerged as a promising and pragmatic medical approach to reduce cancer risk. In the present study, we examined the cancer chemopreventive potential of a flavonoid-rich fraction isolated from the seeds of Carica papaya, a plant traditionally referred to as papaw. The flavonoid-enriched benzene fraction of the aqueous extract exerted its anticancer properties in vitro through cytoprotection, antioxidative and antiinflammatory mechanisms and genoprotection in response to isocyanate-induced carcinogenicity. Medium-term anticarcinogenicity and 2-stage skin papillomagenesis studies conducted in benzopyrene-induced lung carcinogenesis and 7,12-dimethyl benz(a)anthracene-mediated skin papillomagenesis mouse models further validated our in vitro observations. This is the first demonstration of chemopreventive activities of papaya seed products, however, further studies to understand the subtle targets of intracellular signaling pathways, pharmacological profile and toxicological safety of this bioactive fraction are essential to pave the way for successful clinical translation. Our study supports the inverse association between dietary flavonoid intake and cancer risk.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology
  • Anticarcinogenic Agents / pharmacology*
  • Antioxidants / pharmacology
  • Carica / chemistry*
  • Cell Line
  • Cell Proliferation / drug effects
  • Chemoprevention
  • DNA Damage / drug effects
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Flavonoids / pharmacology*
  • HEK293 Cells
  • Humans
  • Mice
  • Plant Extracts / pharmacology*
  • Seeds / chemistry*
  • Stress, Physiological / drug effects


  • Anti-Inflammatory Agents
  • Anticarcinogenic Agents
  • Antioxidants
  • Flavonoids
  • Plant Extracts