Chemical and biological characterization of pectin-like polysaccharides from the bark of the Malian medicinal tree Cola cordifolia.

The bark of Cola cordifolia used in Malian traditional medicine contains unusual types of polysaccharides with immunomodulating activities. We report for the first time on the structure of a polymer designated CC1P1 having the repeating structure [2→)[α-D-Gal(1→3)]α-L-Rha(1→4)α-d-GalA(1→] as determined by NMR and GC/MS. α-Linked Gal is unusual in pectins. The Mw of 135 kDa was determined by SEC-MALLS. CC1P2 (1400 kDa), another polymer, having the same backbone, but this was substituted with α-4-OMe-GlcA, α-2-OMe-Gal and α-Gal as terminal units. CC1P1 shows a high complement-fixing activity, IC50 being 2.2 times lower than the positive pectin control PMII (IC50 appr. 71 µg/mL) while IC50 of CC1P2 is 1.8 times lower. The simple structure of CC1P1 did not activate macrophages, while CC1P2 (100 µg/mL) showed the same potency as the positive controls PMII (100 µg/mL) and LPS (500 ng/mL). No cytotoxicity was detected.

The influence of liposomal formulation factors on the interactions between liposomes and hydroxyapatite.

Liposomes may have potentials as a drug delivery system in the oral cavity; hence, the adsorption to, oral tissues may be of importance. The aim of this study was to find an optimal liposomal formulation with appropriate in vitro stability and which liposomal formulation parameters may be of importance for the interaction to tooth enamel surfaces. Charged liposomes were adsorbed in vitro onto hydroxyapatite (HA), used as a model substance for human dental enamel. For a systematic approach of lipid selection, statistical experimental design and multivariate analysis were conducted to interpret the data. The factors investigated were the type of charge (positive, negative), type of main phospholipid (egg-PC, DPPC, DMPC), type of charged lipid (diacyl-TAP, -ethylPC, -PA, -PG, -PS), the amount of charged component (2.5, 10mol%) and the inclusion of cholesterol in the lipid bilayer. The results indicated that positively charged liposomes expressed significantly higher adsorption levels than the negatively charged ones. The effect of incorporating cholesterol did not turn out to be significant. Both positive egg-PC and DPPC liposomes exhibited high adsorption levels; however egg-PC liposomes were unstable during storage. For positively charged liposomes, the factor "type of main lipid" was found to be of significance for the adsorption, whereas, for negatively charged liposomes, no such important factors were found. Based on the adsorption profile to HA and the in vitro stability in phosphate buffer, the most promising liposomal formulation to target for human enamel in this study was the positively charged DPPC liposomes with 10mol% charged lipid included. However, more experiments are needed to determine the optimum mol% of positively charged lipid for the adsorption onto HA.

Ex vivo mucoadhesion of different zinc-pectinate hydrogel beads.

The objective of this study was to investigate the mucoadhesive properties of pre-swelled hydrogel beads made of six types of pectin from three manufacturers. The types of pectin differed mainly in the degree of methoxylation and degree of amidation. Zinc ions were used as cross-linking agent. The mucoadhesive properties were tested on an inverted fresh porcine small intestine attached to a rotating cylinder. Beads made of pectin with a high degree of methoxylation (70%) showed superior mucoadhesive results compared to the other formulations, which could be correlated to the lower amount of zinc in this formulation, subsequently leading to a lower amount of cross-linking and higher mobility of the polymer chains of these beads. This study therefore also indicated the importance of doing mucoadhesive measurements on relevant formulations, and not basing the understanding solely on investigating polymer solutions. Samples from different manufacturers produced the same results.

Determination of some toxic and essential metal ions in medicinal and edible plants from Mali.

Plants are used in different ways in Mali, among those as medicine and as food. The monitoring of metals in the plants is of great importance for protecting the public from the hazards of possible toxic effects and also for informing the population about the nutritional value of the plants. The concentrations of some toxic and essential metal ions were surveyed in seven medicinal and edible plants from Mali. Dry ashing of the plant material and subsequent use of atomic absorption spectrophotometry were the analytical methodologies used. Iron, manganese, and zinc were found in high concentrations in some of the plants, i.e., 1.4 and 1.5 mg/g iron in Cuminum cyminum and Bombax costatum, respectively, 243 microg/g manganese in Hibiscus sabdariffa, and 62.8 and 67.1 microg/g zinc in Spilanthes oleracaea and B. costatum, respectively, whereas cobalt and cadmium were not detected in any of the plant material studied. The other ions detected, Cr, Ni, Pb, and Cu, were present in minor amounts, in the ranges of 2.2-17.2 microg/g for Cr, 1.6-8.1 microg/g for Ni, 0.7-5.2 microg/g for Pb, and 2.4-17.1 microg/g for Cu. From a toxicological point of view, none of these plants would be harmful for the user by taking in the plant material in the traditional manner, which is preparing an infusion of the plant using amounts not adding up to those necessary to reach a harmful level of the metal ions detected. The plants B. costatum and C. cyminum could be of interest as sources for iron for humans in the case of too low of a level of hemoglobin.