Recent advances in qualitative and quantitative analysis of polysaccharides in natural medicines: A critical review.

Polysaccharides from natural medicines, being safe and effective natural mixtures, show great potential to be developed into botanical drugs. However, there is yet one polysaccharide-based case that has fulfilled the Botanical Guidance definition of a botanical drug product. One of the reasons is the analytical methods commonly used for qualitative and quantitative analysis of polysaccharides fall far behind the quality control criteria of botanical drugs. Here we systemically reviewed the recent advances in analytical methods. A critical evaluation of the strength and weaknesses of these methods was provided, together with possible solutions to the difficulties. Mass spectrometry with or without robust chromatographic separation was increasingly employed. And scientists have made significant progress in simplifying polysaccharide quantification by depolymerizing it into oligosaccharides. This oligosaccharides-based strategy is promising for qualitative and quantitative analysis of polysaccharides. And continuous efforts are still needed to develop a standardized quality control method that is specific, accurate, repeatable, and applicable for analyzing individual components in natural medicine formulas.

A lymphatic route for a hyperbranched heteroglycan from Radix Astragali to trigger immune responses after oral dosing.

Gut barrier makes a huge research gap between in vivo and in vitro studies of orally bioactive polysaccharides: whether/how they contact the related cells in vivo. A hyperbranched heteroglycan RAP from Radix Astragali, exerting antitumor and immunomodulatory effects in vitro and in vivo, is right an example. Here, we determined first that RAP's antitumor activity is immune-dependent. Being undegraded and non-absorbing, RAP quickly entered Peyer's patches (PPs) in 1 h where it directly targeted follicle dendritic cells and initiated antitumor immune responses. RAP was further delivered to mesenteric lymph node, bone marrow, and tumor. By contrast, the control Dendrobium officinale polysaccharide did not enter PPs. These findings revealed a blood/microbiota-independent and selective lymphatic route for orally administrated RAP to directly contact immune cells and trigger antitumor immune responses. This route bridges the research gap between the in vitro and in vivo studies and might apply to many other bioactive polysaccharides.

Radix Astragali polysaccharide RAP directly protects hematopoietic stem cells from chemotherapy-induced myelosuppression by increasing FOS expression.

Radix Astragali polysaccharide RAP has been reported to play a crucial role in hematopoiesis without a clear mechanism. In this study, RAP's effects to enhance the recovery of cyclophosphamide (Cy)-suppressed bone marrow and blood cells is confirmed in vivo first. Confocal micrographs demonstrated the interesting direct binding of FITC-RAP to hematopoietic stem cells (HSC) in bone marrow. RAP protects both mice and human HSC in terms of cell morphology, proliferation, and apoptosis. RNA-sequencing and shRNA approaches revealed FOS to be a key regulator in RAP's protection. These evidences provide an unreported mechanism that RAP directly protects hematopoietic stem cells from chemotherapy-induced myelosuppression by increasing FOS expression.

An oligosaccharide-marker approach to quantify specific polysaccharides in herbal formula by LC-qTOF-MS: Danggui Buxue Tang, a case study.

Polysaccharides have broad bioactivities and are major components of water decoction of herb formulae. However, the quality control of polysaccharides remains a challenge. Oligosaccharide-fragment approach has been considered in elucidating chemical structures of polysaccharides, but never been used for quantitation. Using reference chemicals and a real sample Danggui Buxue Tang (DBT) in this study, an oligosaccharide-marker approach was established to quantify specific polysaccharides. Firstly, linear relationships between parent polysaccharides and hydrolysis-produced daughter oligosaccharides were verified using reference polysaccharides. Then in case of DBT, two fluorescence-labeled oligosaccharides with high specificity to individual parent polysaccharides were selected as markers. They were easily isolated and identified. Their potential in quantification of parent polysaccharides were satisfactorily validated in terms of linearity (r≥0.99), repeatability (RSD ≤ 8.4 %), and spike recovery (≥80 %). This method could be a promising approach for quality assessment of polysaccharides in herbal formulae.

Oligosaccharide-marker approach for qualitative and quantitative analysis of specific polysaccharide in herb formula by ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry: Dendrobium officinale, a case study.

Qualitative and quantitative analysis of polysaccharides in herb formula remain challenge due to the limited choices of analytical methods concerning the intrinsic characteristics of large molecular mass. Herein, an oligosaccharide-marker approach was newly developed for quality assessment of polysaccharides in herbal materials, using Dendrobium officinale as a case study. This method involved partial acid hydrolysis of D. officinale polysaccharide (DOP) followed by p-aminobenzoic ethyl ester (ABEE) derivatization. Two ABEE-labeled oligosaccharides namely, Te-Man-ABEE and Pen-Man-ABEE, were selected as chemical markers due to their high specificity in herb formula. The linear relationship between the content of these two markers and the content of DOP was then successfully established respectively. The linear relationship was further transformed to that between peak area of chemical markers and DOP content so that chemical markers were not necessary to be isolated for analysis. This linear relationship was systemically validated in terms of precision and accuracy. The results showed that these two oligosaccharide-markers presented a good linear relationship with DOP (R2 ≥ 0.997) in the range of 0.68-16.02 µg. These markers also demonstrated satisfactory precision (RSD < 7.0%), and recovery (91.41%-118.30%) in real sample determination. Additionally, there was no significant difference between the results given by the two chemical markers as the RSD values were not more than 7.0%. While concerning the results given by the oligosaccharide-markers and the previously-published polysaccharide marker, the RSD value was not more than 6.4%. These suggest that the oligosaccharide-marker approach is a simple, quick, and reliable method to qualitatively and quantitatively determine of specific polysaccharide in herb formula.

Destiny of Dendrobium officinale Polysaccharide after Oral Administration: Indigestible and Nonabsorbing, Ends in Modulating Gut Microbiota.

Polysaccharides from functional foods have been proved to have diverse bioactivities, but little is known about what exactly happens to these polysaccharides after oral administration and even less about the underlying mechanism of action. Taking the marker polysaccharide (DOP) of Dendrobium officinale as an example, this study aims to demonstrate the dynamic distribution and degradation of orally dosed DOP in mice and in vitro using near-infrared fluorescence imaging and a kind of chromatographic analysis. The results indicate that (1) neither DOP nor fluorescence-labeled DOP (FDOP) was absorbed, (2) both DOP and FDOP were undigested and were quickly degraded to short-chain fatty acids in the large intestine, (3) DOP modulated gut microbiota, which could be associated with DOP's suppression of 4T1 tumor growth in mice. All of these findings suggest that some (maybe not all) bioactive polysaccharides share a common destiny: indigestible and nonabsorbing, ends in modulating bioactivities-associated gut microbiota.

Salidroside induces neuronal differentiation of mouse mesenchymal stem cells through Notch and BMP signaling pathways.

Salidroside (p-hydroxyphenethyl-ß-D-glucoside, SAL), a phenylpropanoid glycoside isolated from a popular traditional Chinese medicinal plant Rhodiola rosea L., possesses multiple pharmacological actions. Previous study showed that SAL could induce rat mesenchymal stem cells (MSCs) to differentiate into dopaminergic neurons and induce mouse MSCs D1 to differentiate into neuronal cells. However, the mechanisms of SAL-induced neuronal differentiation of MSCs still need investigation. In this study, we observed the effects of SAL on neuronal differentiation of D1 cells and the possible involvement of Notch and BMP signaling pathways. SAL inhibited the proliferation, induced neuronal phenotypes, and upregulated the expressions of neuronal-specific marker molecules, such as neuronal enolase 2 (Eno2/NSE), microtubule-associated protein 2 (MAP2), and beta 3 class III tubulin (Tubb3/ß-tubulin III) in D1 cells. SAL not only downregulated the expressions of Notch1 and hairy enhancer of split 1 (Drosophila) (Hes1) but also upregulated the expression of Smad1/5/8 and its phosphorylation (p-Smad 1/5/8). The neuronal differentiation effects of SAL on D1 cells were promoted by a Notch signaling antagonist, DAPT, but attenuated by a BMP signaling pathway antagonist, Noggin. Our findings suggest that SAL might be promising in inducing neuronal differentiation of mouse MSCs mediated by both Notch signaling pathway and BMP signaling pathway.