Phenylethyl isothiocyanate, a compound found in watercress and vegetables such as broccoli and cabbage, may block key processes in cancer development by interfering with and ‘turning off’ the function of a protein called Hypoxia Inducible Factor (HIF), according to findings published in the British Journal of Nutrition.
“The research takes an important step towards understanding the potential health benefits of this crop, since it shows that eating watercress may interfere with a pathway that has already been tightly linked to cancer development,” said lead researcher Professor Graham Packham from the University of Southampton.
The study was supported by the Watercress Alliance.
As tumors develop they need more blood, and begin to stimulate surrounding tissues to grow new blood vessels.
It is suggested that phenylethyl isothiocyanate (PEITC) blocks the development of blood vessels to cancer cells by reducing the activity of HIF – an important positive regulator of blood vessel development.
PEITC has also been shown to induce apoptosis (cell death) in certain cancer cells, and, in some cases, even in cells that are resistant to chemotherapeutic drugs.
Dietary PEITC has been shown to decrease the translation regulator 4E binding protein-1 (4E-BP1) – a protein linked to reducing cancer cell survival and decreased activity of the transcription factor hypoxia-inducible factor (HIF).
The new research investigated the effects of watercress - a rich source of PEITC - on cancer mechanisms on HIF and 4E-BP1.
The researchers observed that crude watercress extracts inhibited cancer cell growth and HIF activity.
Levels of blood plasma PEITC in samples also showed raised levels following the ingestion of watercress.
The authors reported an analysis of 4E-BP1 in blood cells from participants showed significantly reduced 4E-BP1 phosphorylation up to eight hours after eating the watercress, noting that the function of HIF was altered noticeably.
The authors noted their study offers a “new insight into the potential anti-cancer effects of watercress.”
“Although further investigations … are required to confirm these findings, this pilot study suggests that …dietary intake of watercress may be sufficient to modulate this potential anti-cancer pathway,” wrote the researchers.
Source: British Journal of Nutrition
Published online ahead of print, doi: 10.1017/S0007114510002217
“In vivo modulation of 4E binding protein 1 (4E-BP1) phosphorylation by watercress: a pilot study”
Authors: S.S. Syed Alwi, B.E. Cavell, U. Telang, M.E. Morris, B.M. Parry, G. Packham.