Sunday, 13 March 2011

New Treating Agents from Kelp

Search for promising treating agents has come a long way from testing all possible substances, hoping, that something would help, to making treatment with given properties in near future. Currently we are between these two stages with choosing from several hundreds substances and then modifying best of them by chemical means.
Sea dwellers have always been promising from a point of view of a treatment hunter. A group of Russian and foreign biologists is focused on studying fucoidans – sulfated polysaccharides from kelp. During studies researchers have tested biological activity of polysaccharides from various types of kelp and found out that Laminaria saccharina, a close relative of edible kelp, was the most promising source of new treating agents. Recent paper in PLoS ONE describes the study very well.
In the beginning of the studies scientists thought that there was only one polysaccharide of their interest. However, after applying fractionation technique researchers showed that what was considered to be one compound turned out to be a mixture of various polysaccharides and extremely varied structure. Researchers successfully isolated main active component of the mixture – it turned out to be fucoidan. Now scientists want to compare biological activity of fucoidan with other polysaccharides, contained in the extracted mixture. Experiments showed that fucoidan had anti-inflammatory, anti-angiogenic and anticoagulant properties.
As for anticoagulant properties, they aren’t very important for researchers, since plenty of anticoagulant agents already exist. More interesting properties of thepolysaccharide from kelp are anti-inflammatory and anti-angiogenic activities – fucoidan was demonstrated to prevent blood vessel growth inside a tumor. Mentioned properties were studied in culture and on laboratory animals.
Laminaria saccharina
General mechanism of fucoidan’s anti-inflammatory activity is not a mystery, and researchers have found a protein receptor, responsible for binding with the polysaccharide. How fucoidan prevents blood vessels of tumor from growing – this is the question. Researchers are not going to perform any clinical trials of whole fucoidan molecule, because it is almost impossible to certify a sulfated polysaccharide due to extremely poor reproducibility of some tests. Fucoidan itself will not be a treating agent – its low molecular weight fragments, synthesized by biochemical means, will.
Currently researchers proceed with studying fucoidan by means of computer modeling. They virtually break the polysaccharide into low molecular weight fragments and check whether they are able to bind with mentioned receptors. This study is aimed at identifying parts of the polysaccharide, responsible for a particular therapeutic effect.
After mentioned studies promising from a therapeutic point of view fragments of fucoidan will be synthesized in laboratory conditions. Techniques, developed in the Institute of Organic Chemistry of Russian academy of sciences, allow synthesizing long fragments of polysaccharides. Such fragment will later be tested on laboratory animals, and the best ones become the basis for human treating agents.

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