Abstract

Medicinal plants are important for treating illnesses of different kinds all over the world.  The leaves of the tree Combretum glutinosum Perr. ex DC. are amongst the most used remedies in West Africa. In Mali this tree can be found with two types of leaves on the same tree, large and small, growing on different branches. Some healers prefer to use the small leaves if they are available. The object of this paper was to evaluate if the water extract prepared from the two leaves had different immunological properties that could be related to differences in structures of the polysaccharides present in the leaves. Polysaccharides from large and small leaves of Combretum glutinosum were isolated and structurally characterized. Their bioactivities were tested in the human complement fixation assay, as well as their ability to produce nitric oxide from macrophages and to elicit cytokine release from B-cells and dendritic cells. Water extracts from the small leaves gave polysaccharides with a higher proportion of the xylogalacturonan region both for the 50 and 100C water extract than was found to be present in  similar extracts from large leaves. The results of the different bioassays also show higher activities in the polymers from the small leaves, suggesting that the somewhat higher bioactivities in the small leaves can be linked to the xylogalacturonan region of their polymers. These results substantiate the preference that some healers have for the use of small leaves in their practice. 

Key words: Combretum glutinosum, pectin, complement, cytokine, B-cell, dendritic cell.