No abstract

No abstract

Polysaccharides were extracted from seven plants endemic to Gabon to study their potential immunological activities. Peripheral blood mononuclear cell (PBMC) (5 × 10 5 cells/mL) proliferation, cytokine and immunoglobulin G (IgG) assays were performed after stimulation with different concentrations of polysaccharide fractions compared with lipopolysaccharides (LPS) and concanavalin A (ConA) from healthy volunteers. The culture supernatants were used for cytokine and IgG detection by enzyme-linked immunosorbent assay (ELISA). The results show that pectin and hemicellulose extracts from Uvaria klainei, Petersianthus macrocarpus, Trichoscypha addonii, Aphanocalyx microphyllus, Librevillea klaineana, Neochevalierodendron stephanii and Scorodophloeus zenkeri induced production levels that were variable from one individual to another for IL-12 (3-40 pg/mL), IL-10 (6-443 pg/mL), IL-6 (7-370 pg/mL), GM-CSF (3-170 pg/mL) and IFN-γ (5-80 pg/mL). Only hemicelluloses from Aphanocalyx microphyllus produce a small amount of IgG (OD = 0.034), while the proliferation of cells stimulated with these OPEN ACCESSMolecules 2014, 19 18544 polysaccharides increased up to 318% above the proliferation of unstimulated cells. However, this proliferation of PBMCs was abolished when the pectin of some of these plants was treated with endopolygalacturonase (p < 0.05), but the trend of cytokine synthesis remained the same, both before and after enzymatic treatment or saponification. This study suggests that these polysaccharides stimulate cells in a structure-dependent manner. The rhamnogalacturonan-I (RGI) fragment alone was not able to induce the proliferation of PBMC.

Objective: This study aimed to valorize two medicinal plants used against Loa loa filarial in Gabon. Material and Methods: Powders of leaves of Senna occidentalis and stems and leaves of Cissus quadrangularis were proposal to successive extractions by solvents with increasing polarities (cyclohexan, dichloromethan, methanol and demineralized water). Qualitative Phytochemistry screening was established using the standard color and/or precipitation reactions. Results: The results reveal the predominance of total sugar, alkaloids, and phenols in all extracts. Cathechic tannins, reducing sugar, and flavonoids on many extracts were tested. Gallic tannins and coumarins are found in some extracts. They are very few quinones, triterpenes or sterols in the two species. Conclusion: Some secondary metabolites have proved filaricide activities already. The abundance of chemical compounds present in these medicinal plants would justify their usage. However, the evaluation of biological activities on the Loa loa filarial along with toxicity remains unexplored.

Plants are commonly used throughout the world, most particularly in Africa for different purposes including use as drugs, food and cosmetics. Polysaccharides were extracted from the cell walls of seven plants endemic to Gabon, Uvaria klainei, Petersianthus macrocarpus, Trichoscypha addonii, Aphanocalyx microphyllus, Librevillea kleaneana, Neochevalierodendron stephanii and Scorodophloeus zenkeri. Pectins and hemicelluloses from these plants were extracted using ammonium oxalate and potassium hydroxide and their sugar compositions were determined using gas chromatography. These fractions were used to test their toxicity compared to standard products such as mercuric chloride (HgCl 2), 4-Nitro-quinoloine (4-NOQ), 2-Amino-Anthracene (2AA) and ivermectin. Their anticoagulant capacity was tested by measuring Activated Partial Thromboplastin Time (APTT), prothrombin time (PT/QT) compared to snake venom and the heparin response. The results showed that these extracts had no cytotoxicity since the IC 50 of polysaccharide extracts and ivermectin varied from 456.62 to 892.42 µg/mL compared to standard toxic HgCl , 4-NOQ, 2AA: 1.8-22 µg/mL. No genotoxicity or pro-genotoxicity was found: the SOS test Inhibiting Factor (IF) from pectins and hemicelluloses varied from 0.4 to 1.2 compared to the standard genotoxic 4-NOQ, with an IF of 9.33. Acute toxicity was not observed, as indicated by the minimum inhibition at 20% (MIC 20) that varied from 25.45 to 65.85 for polysaccharides, while the standard toxic level was at a MIC 20 of 0.0284. However, in vitro anticoagulant activities were detected. De-esterification and enzyme degradation of the homogalacturonan pectin chains did not change the hemostatic trend of pectic fractions.