An anti-complementary polysaccharide with immunological adjuvant activity from the leaf parenchyma gel of Aloe vera

The aim of the study is to develop new substances with immunomodulatory activity. To this end, extracts from plants used in traditional medicine are used as starting material. This study deals with the mucilagenous leaf-gel of Aloe vera which is well reputed for its therapeutical effect on inflammatory-based disorders. The purification of an aqueous gel-extract guided by inhibition of complement activity in HPS is described. Using anion-exchange and gel permeation chromatography a highly active polysaccharide fraction was isolated, that is present in the gel in various chain lengths. The polysaccharides consist of several monosaccharides of which mannose is dominant. The inhibition is based on alternative pathway activation, resulting in consumption of C3. With respect to their biological activity the polysaccharides inhibit the opsonization of zymosan in HPS and display adjuvant activity on specific antibody production and the induction of delayed type hypersensitivity in mice.