Immunomodulatory activity of polysaccharides isolated from Alchornea cordifolia

Abstract

Ethnopharmacological relevance Extracts of leaves from different species of the genus Alchornea have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts. Objective The aim of this study was to evaluate the immunomodulatory activity of polysaccharides isolated from the leaves of Alchornea cordifolia. Materials and methods Water-soluble polysaccharides from leaves of A. cordifolia were extracted and fractionated by DEAE-cellulose, Diaion HP-20, and size-exclusion chromatography. Molecular weight, sugar analysis, and other physical and chemical characterization of the fractions were performed. Immunomodulatory activity of the polysaccharide fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO) and cytokine production. Activation of mitogen activated protein kinases (MAPK) was also assessed using a phospho-MAPK array. Activation of nuclear factor κB (NF-κB) was measured using an alkaline phosphatase reporter gene assay in THP1-Blue monocytic cells. Results Six polysaccharide fractions from A. cordifolia were isolated. Fractions containing type II arabinogalactan had potent immunomodulatory activity. Particularly, the parent fraction AP-AU and its high-molecular weight sub-fraction AP-AU1 (average Mr was estimated to be 39.5 kDa) induced production of NO and cytokines [interleukin (IL)-1β, -6, -10, tumor necrosis factor (TNF)-α, and granulocyte macrophage-colony stimulating factor (GM-CSF)] in human peripheral blood mononuclear cells and human and murine monocyte/macrophages cell lines in vitro. Furthermore, treatment with AP-AU1 induced phosphorylation of Akt2, p38δ/p38γ, p70S6K1, RSK2, and mTOR, as well as stimulation of NF-κB transcriptional activity. Conclusion Our results provide a molecular basis to explain a portion of the beneficial therapeutic properties of water extracts from A. cordifolia leaves in traditional folk medicine of Africa.

Immunomodulatory activity on macrophage of a purified polysaccharide extracted from Laminaria japonica

“…3E, among the tested dosage, LJP-31 dose-dependently resulted in an increase of IL-10 production as well as TNF-␣, IL-1␤ and IL-6. These results are consistent with the effects of some other polysaccharides on the cytokine production by macrophages (Zhang & Dai, 2011;Kim et al, 2012;Kouakou et al, 2013). It has been reported that the macrophages are able to be converted into M1 cells and M2 cells when exposed to various stimulators.…”

Optimization of Polysaccharide-Rich Fractionation From Morinda Citrifolia L. Fruit Based on Immunostimulatory Effect in Vitro

“…Phagocytic ratio showed the macrophages amount in 100 macrophages which actively phagocyted latex, while phagocytic Index showed the number of latex which were phagocyted by 100 macrophages. According to Kouakou et al (2013), a common feature of plant polysaccharides that modulate macrophage function may be higher molecular weight as were found previously from some researchs (Schepetkin et al, 2008;Xie et al, 2007;and Xie et al, 2008) that immunomodulatory activity positively correlated with increased molecular weight of various plant polysaccharides. It has been reported that polysaccharides are able to bind to phenolic substances by intermolecular interactions (Renard et al, 2001), which changing the molecular conformation of carbohydrates.…”

Peripheral Blood Mononuclear Cells

“…PBMCs were pre-incubated with the vitamin K antagonist for 30 min before the cells were stimulated with PHA for 48 h. The cytokines secreted into the supernatants were analyzed by ELISA. Also, in a recent report cytokine secretion and activation of mitogen-activated protein kinases (MAPK) in response to polysaccharides isolated from Alchornea cordifolia (Kouakou et al 2013 ) was studied. Evaluation of the effects of polysaccharides on the activation status of an array of different MAPKs was done using a phospho-MAPK kit.…”