ABSTRACT
It has been widely believed for several years that many of the beneficial effects of aloe leaf extracts lie in their carbohydrates. The thick fleshy leaves contain both cell wall carbohydrates, such as celluloses and hemicelluloses, as well as storage carbohydrates, such as acetylated mannans, arabinans and arabinogalactans. Like all cells, they also contain many diverse glycoproteins. The acetylated mannan is the primary polysaccharide in the pulp (inner clear portion of the leaf) and has been most widely studied. It has been claimed to possess many therapeutic properties, including immune stimulation. The general structure of the mannan (β1→4 linked mannose residues and acetylation) has been well-defined, although many structural features such as degree of acetylation, glucose content, and molecular weight remain to be defined, especially in relation to functional properties, extraction conditions, and harvesting times. There may well be two types of mannans in the pulp, a pure mannan and a glucomannan. There is very little information available on the enzymes used to modify or synthesize the mannan or other aloe carbohydrates. Aloe mannan is indeed a unique polysaccharide. Future studies on the structure-function relationship will certainly yield more insight into its chemical and functional properties.
