Pectic polysaccharides isolated from Malian medicinal plants protect against Streptococcus pneumoniae in a mouse pneumococcal infection model.

The aim of this study was to investigate whether the pectic polysaccharides BP-II, Oc50A1.I.A and CC1P1 isolated from the Malian medicinal plants Biophytum petersianum, Opilia celtidifolia and Cola cordifolia, respectively, were able to protect against Streptococcus pneumoniae infection in mice. The pectin preparations were administered intraperitoneally 3 h before challenge with S. pneumoniae serotype 6B. Blood samples were obtained from all animals before and at 3 h, 24 h and 72 h after challenge with the pneumococci. The number of bacteria in blood was recorded and the blood concentration of a range of cytokines measured. The pretreatment with BP-II, Oc50A1.I.A and CC1P1 demonstrated a protective activity against S. pneumoniae serotype 6B infection, albeit at different range of concentrations. The pectins showed no direct antibacterial effects towards S. pneumonia; however, they induced the production of a range of cytokines and chemokines. We have previously shown that BP-II, Oc50A1.I.A and CC1P1 exhibit complement fixation activity and also that BP-II and Oc50A1.I.A stimulate macrophages to produce NO. The observed clinical effect might therefore be linked to the ability of the pectic polysaccharides to stimulate the innate immune system.

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

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.