La thérapie par les plantes en Afrique: activités immunostimulantes des polysaccharides de la paroi végétale

Phytotherapie 01/2010; 8(4):223-230. DOI: 10.1007/s10298-010-0567-4


Dans cette revue, nous mettons en avant le potentiel thérapeutique des polysaccharides isolés à partir des parois végétales
des plantes médicinales africaines. In vivo, la paroi végétale joue un rôle important dans le contrôle de la physiologie de
la plante (croissance cellulaire, mécanismes de défense de la plante, morphologie de la plante). Principalement composée de
polysaccharides comme la cellulose, les hémicelluloses ou de pectines, la relation entre la structure chimique de ces polysaccharides
et leurs fonctions biologiques a fait l’objet de très nombreuses études. Des extraits de ces parois, principalement polysaccharidiques,
isolés à partir de plantes sont également couramment utilisés comme « remède traditionnel» en Afrique. Dans cette revue, nous
présentons quelques plantes médicinales africaines pour lesquelles la structure chimique de certains extraits polysaccharidiques,
présentant souvent une activité immunomodulatoire, a été déterminée. Ce type d’étude et d’approche, encore marginale, gagnerait
à être généralisé aux autres plantes médicinales africaines jusqu’alors peu étudiées. Cette propriété immunomodulatoire de
certains extraits polysaccharidiques pourrait constituer un complément thérapeutique de choix chez des patients immunodéprimés
ou immunodéficients.

This review article aims to draw attention to therapeutic potential of plant cell wall polysaccharides isolated from African
medicinal plants. Plant cell wall, or plant cell extracellular compartment, consists on various polysaccharides having different
chemical structures. Among these polysaccharides, cellulose, hemicelluloses and pectin polysaccharides are the predominant
ones, and play an important role in controlling several biological processes like cell growth and morphogenesis, or defense
mechanisms. The structure-function relationship of plant cell wall polysaccharides have been extensively studied, regarding
their in vivo biological functions. Here, we have partially described the chemical structure of several biologically active
hemicelluloses or pectin polysaccharides extracts, isolated from different African medicinal plants. It appears that these
polysaccharides taken individually are able to modulate the activity of the mammal immune system in different manner, providing
an interesting complementary therapy to immune deficient patients for instance. Further investigations on cell wall polysaccharide
structure-biological activity relationship of the numerous unexplored medicinal plants are therefore strongly suggested.

Mots clésPolysaccharides-Plantes médicinales-Immunomodulatoire-Hémicelluloses-Pectines-Immunodéficient-Structure des polysaccharides et fonctions biologiques
KeywordsPolysaccharides-Medicinal plants-Immune-modulator-Hemicelluloses-Pectins-Immune-deficient-Structure of polysaccharides and biological function

843 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Herbal and traditional medicines are being widely used in practice in many countries for their benefits of treating different ailments. A large number of plants in Morocco were used in folk medicine to treat immune-related disorders. The objective of this study is to evaluate the immunomodulatory activity of protein extracts (PEs) of 14 Moroccan medicinal plants. This activity was tested on the proliferation of immune cells. The prepared total and PEs of the plant samples were tested using MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide) assay on the splenocytes with or without stimulation by concanavalin-A (Con-A), a mitogenic agent used as positive control. The results of this study indicated different activity spectra. Three groups of activities were observed. The first group represented by Citrullus colocynthis, Urtica dioica, Elettaria cardamomum, Capparis spinosa and Piper cubeba showed a significant immunosuppressive activity. The second group that showed a significant immunostimulatory activity was represented by Aristolochia longa, Datura stramonium, Marrubium vulgare, Sinapis nigra, Delphynium staphysagria, Lepidium sativum, Ammi visnaga and Tetraclinis articulata. The rest of the plant extracts did not alter the proliferation induced by Con-A. This result was more important for the PE than for the total extract. In conclusion, this study revealed an interesting immunomodulating action of certain PEs, which could explain their traditional use. The results of this study may also have implications in therapeutic treatment of infections, such as prophylactic and adjuvant with cancer chemotherapy.
    Toxicology and Industrial Health 02/2012; 29(3). DOI:10.1177/0748233711430972 · 1.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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.
    Molecules 11/2014; 19(11):18543-57. DOI:10.3390/molecules191118543 · 2.42 Impact Factor