Abstract
Polysaccharides were extracted from seven plants endemic to Gabon to study their potential immunological activities. Peripheral blood mononuclear cell (PBMC) (5 × 105 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 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.
Highlights
Infectious diseases and immune-system diseases are still highly prevalent despite the modern treatments available
Magnoliales is represented by Uvaria klainei, an Annonaceae only found in Gabon
Four Fabaceae-Caesalpinioideae in the Fabales class are represented by Aphanocalyx microphyllus, which is found throughout central Africa; Librevillea klaineana is only found in Gabon and is used to treat venereal disease; Neochevalierodendron stephanii, found in the equatorial forest, is used as an antibiotic; Scorodophloeus zenkeri, found throughout Africa, is used as a spice and treats high blood pressure and respiratory disease
Summary
Infectious diseases and immune-system diseases are still highly prevalent despite the modern treatments available (grafting, thymic injection, etc.). Adaptive immunity requires a reaction between a foreign body (antigen) and a receptor in the host These receptors are carried by lymphocyte cells (TCR, BCR), which are divided into two families: B lymphocytes and T lymphocytes. Under the influence of certain stimuli, the immune reaction can be oriented toward the Th1 subset, characterized by the prominent synthesis of cytokine-like interferon-γ, IL-2, etc., or Th2, characterized by the prominent synthesis of IL-4, IL-5, IL-6 and IL-10 [4] This suggests that the course of the immune response can be influenced by external factors. Most of the studies on plants are based on their secondary metabolites, a few studies have investigated the immunostimulant activities of plant polysaccharides [8,9,10]. Few studies have been carried out on parietal polysaccharides from endemic plants in Gabon, the subject of this study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
