Rasayana properties of Ayurvedic herbs: Are polysaccharides a major contributor

Rasayana constitutes a very important class of Ayurvedic herbs, which acts as rejuvenators and tonic. Despite intensive research on evaluating the medicinal basis for the purported medical benefits of Rasayana herbs, still a specific chemical guiding principle for the characterization of these herbs in one single category is unclear. Here we explore the possibility that polysaccharides play a key role in Rasayana properties exhibited by medicinal plants. Further on this could be a possible field for exploration for a common factor present in some of the Ayurvedic herbs. The present review covers a literature spanning from 1956 to 2011. Some translations of traditional Ayurvedic texts dating back to the first century AD have been referred to as well. In our assessment of the present literature and studies carried out it is presupposed that the presence of benevolent plant polysaccharides must be one of the important features symbolizing a common effectiveness in most of the Ayurvedic Rasayana herbs. Of the many plant metabolites polysaccharides have not so far been considered and studied effectively compared to other secondary metabolites like saponins, alkaloids, etc. Although all the results reported until now suggest a major contribution of polysaccharide towards the maintenance of physiological homeostasis, which is the guiding principle of Rasayana therapy. The present review is an attempt to find a connective link between the concept of Rasayana and well-being; and the role of plant polysaccharides. Lack of clinical information on number of polysaccharides showing promise is a limiting factor for a complete understanding. It is also important to carry out a molecular interaction study to understand the behavior of polysaccharides discussed in the present review.