Characteristics and immune-enhancing activity of pectic polysaccharides from sweet cherry (Prunus avium)

Structural Features of Three Hetero-Galacturonans from Passiflora foetida Fruits and Their in Vitro Immunomodulatory Effects

“…Meanwhile, all these three hetero-galacturonans could promote the secretion of IL-6 ( Figure 4D) with a significant concentration-dependent manner at the concentrations of 4 and 20 µg/mL (p < 0.05). These results of the present study were in agreement with the studies on hetero-galacturonans obtained from sweet cherry and stem lettuce [10,11]. Therefore, these results suggested that PFP2, PFP3, and PFP4 may play an immunomodulatory role through promoting the secretion of TNF-α, IL-6, and NO in RAW264.7 macrophages, which are essential for killing pathogens, microorganisms, and coordinating various biological activities as intracellular messenger molecules [5].…”

“…After cell adhesion had formed or happened for 24 h, the conditioned culture mediums were replaced with 1 mL new DEME culture medium, in which containing different concentrations of PFP2, PFP3, and PFP4 (0.032, 0.16, 0.8, 4, or 20 µg/mL) or culture medium (negative control) for 24 h. In addition, cells cultured in LPS (1 µg/mL) were used as positive control. To exclude the probability of LPS contamination during the polysaccharide isolation period, each polysaccharide fraction sample (20 µg/mL) was blended with various concentrations of polymyxin B (0, 100, or 200 µg/mL) for 0.5 h before added to the medium [10]. The conditioned culture medium was collected and centrifuged (12,000 rpm, 10 min, 4 • C) to determine the content of NO, TNF-α and IL-6 from RAW264.7 cells by using commercial kits in accordance with the manufacturer's instructions.…”

“…Signals within the range of 3.32−5.39 ppm ( 1 H NMR) and 59.55−175.20 ppm ( 13 C NMR) represented a typical characteristic of polysaccharides. All the 1 H and 13 C (Table 3) were portioned as thoroughly as possible according to 2D NMR analysis and on literature values [6,10,[24][25][26][27][28][29].…”

“…Based on the proton chemical shifts, 1 H and 13 C chemical shifts indicated by 1 H-1 H correlation spectroscopy (COSY) and heteronuclear single quantum coherence (HSQC) spectra (Figure 3), the chemical shifts of residues D and G consistent nearly with the reported values for a methyl glycoside of 1, 4-linked GalpAc and 1, 3, 4-linked GalpAc. In consideration of the results of FT-IR spectra, methylation analysis and NMR results, it could be deduced that the backbones of PFP2, PFP3, and PFP4 were mainly composed of (1→4)-linked-GalpAc and (1→3, 4)-linked-GalpAc residues [6,10,26,30]. .82) ppm were appointed to the C-1(H-1) of T-linked Galp residues (residues C), (1→3)-linked Galp residues (residues F) and (1→3,6)-linked Galp residues (residues H), respectively [27].…”

“…Among the salt-eluted polysaccharides, such as galactans, glucans, galacturonans, galacturonans have attracted more attention in modern pharmacology [5][6][7]. It is one kind of polysaccharides with a backbone of galactopyranouronic (GalpAc) residues and mostly distributed in plants as heterozygotes, which have extensively gained concerns because of their multiple biological properties, especially the immunomodulatory activities [8][9][10][11][12]. Studies have shown that these galacturonans derived from different plants (such as sweet cherry, stem lettuce, Gynostemma pentaphyllum tea, and elderflowers) with different molecular weights (9~2490 kDa) and different percentages of galacturonic acid (17.4%-77.18%) exhibited various immunoregulatory effects on macrophages by enhancing production of NO and cytokines at the minimum effective concentration (0.8~100 µg/mL).…”