Xylans from natural sources

For thousands of years, nature has provided humankind with a large variety of materials for the most diversified applications for its survival, such as food, energy, medicinal products, protection and defense tools, and others. The pharmaceutical industry has benefitted from such diversity of biomaterials and has exploited the use of natural products as sources of both drugs and excipients. One example of a promising biomaterial for pharmaceutical use is xylan, a hemicellulose largely found in nature, being considered the second most abundant polysaccharide after cellulose. 

D-Arabinan is the only pentoglyccm other than D-xylan found in nature, and it is widely distributed as one of the three components of the pectic substances. Separation of arabinan from accompanying galactan is difficult. The pectin from peanuts (Arachis hypogea) is low in galactan and is a convenient source of pure arabinan. On hydrolysis it yields L-arabinose as the sole product. Structuralstudiesindicate that the backbone of the molecule is a chain of -l-( i 5) -linked L-arabinofuranose residues, with single L-arabinofu-ranose residues a-L-(i -> 3)-linked to every second unit on the main chain. 

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