Pectin may protect against cancer: Study
Researchers from the Institute of Food Research report that galactan side-chain may bind and inhibit galectin 3 (Gal3), linked to cancer progression.
"This first step opens the way to a new and exciting area of research in bioactive carbohydrates," said Professor Vic Morris, the lead researcher of the study.
The researchers report their findings in the Federation of American Societies for Experimental Biology (FASEB) Journal.
Extracted pectin (E440) with worldwide production estimated at 35,000 tonnes a year, is currently widely used as gelling agents in jams, confectionary, and bakery fillings, and stabilisers in yoghurts and milk drinks.
Players in the pectin field are starting to eye the health ingredients market. But many remain reluctant to make any kind of health claims until more science is built up. And for pectin, the science has indicated a potential prebiotic effect, the important fibre content, and potential cardiovascular benefits by lowering LDL cholesterol.
Pectin structure is the key
The chemical structure of pectin is based on a chain of repeating galacturonic acid units. In this “smooth” backbone, regions where galacturonic acid is substituted by rhamnose that has lots of sidechains of various neutral sugars branching off – termed “hairy regions”. This type of pectin is called rhamnogalacturonan I (RGI).
Alkaline and acid treatments of pectin – as is performed industrially - lead to modified pectin. Such treatments change the structure of pectin and can lead to the release of modified “hairy regions”, said the researchers, and “preferential removal of arabinose residues”.
“The removal of arabinose appears to promote enhanced accessibility to the galactan chains and allows several individual galactan chains to bind to … Gal3,” said the researchers.
“The experimental data support the suggested molecular hypothesis for the anticancer action of modified pectin by demonstrating that bioactive fragments from pectin can bind specifically to Gal3,” they added.
Prof Morris confirmed that the research area is ongoing, with the next stage aiming to identify how pectin can be taken up by the body and released so it can exert its effect on cancer cells.
The research could also result in functional foods with added bioactive pectin, said Prof Morris.
The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
Source: FASEB JournalPublished online ahead of print, 2 October 2008, doi:10.1096/fj.08-106617“Recognition of galactan components of pectin by galectin-3”Authors: A.P. Gunning, R.J.M. Bongaerts, V.J. Morris
