β-(1→3)-Glucan-mannitol conjugates: scope and amazing results.

It is well known that β-(1→3)-Glucans present high applicative potential in human health as immunostimulating agents. Numerous studies have highlighted this, but mainly used native polysaccharides extracted from various natural sources. These compounds are therefore inevitably polydisperse but also present structures that are not homogeneous, in an analytical point of view. This is the reason why we have achieved the chemical synthesis of small glucan-mannitol derivatives especially found in brown seaweeds. The targets differ from each other by the nature of the conjunction between the laminaribiose and the mannose or mannitol, i.e., (1→6) or (1→3). We established that (I) these molecules were efficiently obtained from glucose, laminaribiose and/or mannose derivatives; (II) the synthetic plan has to be adapted to the first connection between a glucosyl entity and the mannosyl residue; and (III) resulting pure compounds may be used as the standard for analytical purposes.