Structural analysis of a soluble polysaccharide GSPA-0.3 from the root of Panax ginseng C. A. Meyer and its adjuvant activity with mechanism investigation.

A novel polysaccharide (GSPA-0.3) was isolated and purified from the root of cultivated Panax ginseng C. A. Meyer, and its structure, adjuvant activities, and mechanisms for inducing the maturation of mouse dendritic 2.4 cells (DC2.4) were extensively studied. Fraction GSPA-0.3, mainly composed by the galacturonic acid, galactose, arabinose, glucose, rhamnose, mannose, and xylose, had a molecular weight of 62,722 Da. The main chain of GSPA-0.3 was composed of →3)-α-L-Rhap-(1→, →4)-α-D-GalpA-(1→, and →3, 4)-α-D-GalpA-(1→. Branched chains comprised α-L-Araf-(1→3, 5)-α-L-Araf-(1→5)-α-L-Araf-(1→, α-D-Glcp-(1→6)-α-D-Glcp-(1→6)-α-D-Glcp-(1→, ß-D-Galp-(1→4)-ß-D-Galp-(1→4)-ß-D-Galp-(1→, and α-D-GalpA-(1→ units connected to the C3 position of →3, 4)-α-D-GalpA-(1→. In vivo, GSPA-0.3 was found to stimulate the production of IgG, IgG1, and IgG2a; increase the splenocyte proliferation index; and promote the expression of GATA-3, T-bet, IFN-γ, and IL-4 in H1N1 vaccine-immunized mice. Moreover, GSPA-0.3 significantly increased the levels of neutralizing antibodies in the mice, and its adjuvant activity was found to be superior to aluminum adjuvant (Alum adjuvant). Mechanistic investigations showed that GSPA-0.3 activated the TLR4-dependent pathway by upregulating the expressions of TLR4, MyD88, TRAF-6, and NF-κB proteins and gens. The results presented herein suggested that GSPA-0.3 could significantly promote the efficacy of the H1N1 vaccine by modulating Th1/Th2 response via the TLR4-MyD88-NF-κB signaling pathway.

Binding mechanism and bioavailability of a novel phosvitin phosphopeptide (Glu-Asp-Asp-pSer-pSer) calcium complex.

Phosvitin has excellent calcium binding capacity, related to its phosphopeptides. The phosphopeptides may be used as functional ingredients for improving calcium bioavailability, but the calcium-binding mechanism is unclear. In this study, a novel phosvitin phosphorylated pentapeptide (Glu-Asp-Asp-pSer-pSer, EDDpSpS) was selected to prepare an EDDpSpS calcium complex (EDDpSpS-Ca), and the calcium-binding mechanism and bioavailability investigated. The calcium-binding capacity of EDDpSpS was up to 468 ± 152.80 mg/g. Calcium ions prompted the folding of the EDDpSpS structure to form spherical nanoparticles. The calcium binding sites of EDDpSpS involved peptide bonds, carboxyl, amino, and phosphate groups. Molecular forces involved in these interactions were electrostatic in nature. Moreover, EDDpSpS-Ca had excellent bioavailability when compared to CaCO3, calcium lactate, and d-calcium gluconate. This study revealed the calcium-binding mechanism of phosvitin phosphopeptide, and suggested that EDDpSpS-Ca has the potential to be a novel, efficient, and promising calcium supplement.

Investigation of two Flacourtiaceae plants: Bennettiodendron leprosipes and Flacourtia ramontchi.

Investigations of two Flacourtiaceae plants, Bennettiodendron leprosipes and Flacourtia ramontchi, resulted in the isolation and structural elucidation of six new constituents including two phenolic glycosides ( 1 and 2), one lignan ( 3), two lignan glycosides ( 4 and 5), and a monoterpene glycoside ( 6), together with 22 known compounds ( 7- 28). The structures of the new compounds were elucidated by spectroscopic analysis and chemical methods. The selected isolates 1, 2, 8- 10, 22- 26, and some phenolic glycosides 29- 42 previously isolated from another Flacourtiaceae plant, Itoa orientalis, were tested against snake venom phosphodiesterase I (PDE I) activity. The result indicated that 22, 30, 32, 34, and 40 exhibited moderate inhibitory activities against PDE I with the values ranging from 13.15 to 20.86 %, and 1, 8, 10, 25, 31, 33, 35, 38, 39, and 41 showed weak inhibitory activity.