Chemical and biological characterization of polysaccharides from wild and cultivated roots of Vernonia kotschyana

Abstract

Ethnopharmacological relevance: In Malian traditional medicine the roots of Vernonia kotschyana are used for treating gastric ulcer and gastritis. In 2006, 9000kg of roots from Vernonia kotschyana were used to produce Gastrosedal, an ameliorated traditional medicine in Mali. Harvesting from the wild, the main source of raw material, is causing a growing concern of diminishing populations of the plant, and Vernonia kotschyana is now being cultivated in several areas around Mali. In the current study the structures and bioactive properties of isolated polysaccharides from wild and cultivated Vernonia kotschyana were compared.

Materials and methods: Pectin- and inulin-type polysaccharides were isolated from the roots of cultivated and wild Vernonia kotschyana. The isolated polysaccharides were investigated regarding their chemical compositions, and for their abilities to fixate human complement and activate macrophages from a mouse macrophage cell line.

Results: No significant differences in the carbohydrate composition of the fractions isolated from the cultivated versus the wild roots were observed. A previously reported pectic arabinogalactan Vk2a was found in both the cultivated and the wild roots in this study, and exhibited potent complement fixation activity, and a moderate activation of macrophages.

Conclusions: The present study has shown that the cultivated roots of Vernonia kotschyana contain the same types of bioactive polysaccharides as the wild roots. It is therefore preliminarily feasible for the cultivated roots of Vernonia kotschyana to be used as a herbal medicine to replace the wild roots.