Preparation and antiherpetic activities of chemically modified polysaccharides from Polygonatum cyrtonema Hua

Polysaccharides from Traditional Chinese Medicines: Extraction, Purification, Modification, and Biological Activity

Traditional Chinese Medicine (TCM) has been used to treat diseases in China for thousands of years. TCM compositions are complex, using as their various sources plants, animals, fungi, and minerals. Polysaccharides are one of the active and important ingredients of TCMs. Polysaccharides from TCMs exhibit a wide range of biological activities in terms of immunity- modifying, antiviral, anti-inflammatory, anti-oxidative, and anti-tumor properties. With their widespread biological activities, polysaccharides consistently attract scientist's interests, and the studies often concentrate on the extraction, purification, and biological activity of TCM polysaccharides. Currently, numerous studies have shown that the modification of polysaccharides can heighten or change the biological activities, which is a new angle of polysaccharide research. This review highlights the current knowledge of TCM polysaccharides, including their extraction, purification, modification, and biological activity, which will hopefully provide profound insights facilitating further research and development.

Comparison of the anti-duck hepatitis A virus activities of phosphorylated and sulfated Astragalus polysaccharides

Duck hepatitis A virus (DHAV) (Picornaviridae) causes an infectious disease in ducks which results in severe losses in duck industry. However, the proper antiviral supportive drugs for this disease have not been discovered. Polysaccharide is the main ingredient of Astragalus that has been demonstrated to directly and indirectly inhibit RNA of viruses replication. In this study, the antiviral activities of Astragalus polysaccharide (APS) and its derivatives against DHAV were evaluated and compared. APS was modified via the sodium trimetaphosphate and sodium tripolyphosphate (STMP-STPP) method and chlorosulfonic acid-pyridine method to obtain its phosphate (pAPS) and sulfate (sAPS), respectively. The infrared structures of APS, pAPS, and sAPS were analyzed with the potassium bromide disc method. Additionally, the antiviral activities were evaluated with the MTT ((4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) method in vitro and the artificial inoculation method in vivo. The clinical therapy effects were evaluated by mortality rate, liver function-related biochemical indicators, and visual changes in pathological anatomy. The anti-DHAV proliferation effects of APS, pAPS, and sAPS on the viral multiplication process in cell and blood were observed with the reverse transcription-polymerase chain reaction method. The results revealed that pAPS inhibited DHAV proliferation more efficiently in the entire process of viral multiplication than APS and sAPS. Moreover, only pAPS significantly improved the survival rate to 33.5% and reduced the DHAV particle titer in the blood as well as liver lesions in clinical trials. The results indicated that pAPS exhibited greater anti-DHAV activity than APS and sAPS both in vitro and in vivo.

Effect of Astragalus polysaccharide and its sulfated derivative on growth performance and immune condition of lipopolysaccharide-treated broilers

This study evaluates the immunomodulating activities of Astragalus polysaccharide (APS) and sulfated APS (SAPS) in LPS-infected broiler chicks. SAPS was derived using the classic chlorosulfonic acid-pyridine method. On day 16, the birds were injected intramuscularly with 0.5 mL of either saline, APS (4 or 8 mg/kg of body weight (BW), shorten as APS-4 or APS-8) or SAPS (4 or 8 mg/kg of BW, shorten as SAPS-4 or SAPS-8) once a day for three successive days. On days 19 and 20, the birds were intraperitoneally injected with 0.5 mL of LPS (1mg/kg of BW). Saline was used as blank control. Compared with the blank control, LPS-treated birds showed lower daily body weight gain (BWG), average daily feed intake (ADFI), villus height and intraepithelial lymphocytes (IEL) number in jejunum, and higher feed conversion ratio (FCR, feed:gain), spleen index, plasma NO concentration, blood heterophil:lymphocyte (H:L) ratio, and the production of NO in the blood T lymphocytes. Compared with the LPS group, birds in APS-4, SAPS-4 and SAPS-8 groups showed decreased FCR (P<0.05). Moreover, SAPS increased BWG and jejunal villus height (P<0.05) at 8 mg/kg BW. Plasma NO concentration was lower in APS-8 group than that in LPS group (P<0.05). Both APS-8 and SAPS-8 treatments elevated the number of jejunal IEL (P<0.05), and decreased blood H:L ratio (P<0.05), respectively. Administration of APS or SAPS did not affect the ADFI, immune organ index, crypt depth and mucosal thickness of the jejunum, and the number of goblet cell. Our findings suggested that APS and SAPS possessed dose-dependent growth-promoting and immunomodulating effect, and was a potential development direction for immunomodulator under early LPS stimulation condition.

Antiherpetic mechanism of a sulfated derivative of Agaricus brasiliensis fruiting bodies polysaccharide

OBJECTIVE

To study the anti-herpes simplex virus (HSV) activity of a (1→6)-(1→3)-β-D-glucan isolated from Agaricus brasiliensis fruiting bodies (FR) as well as its chemically sulfated derivative (FR-S).

METHODS

The antiherpetic activity and mechanism of action was studied by viral plaque assay applying different methodological strategies.

RESULTS

Although FR presented no in vitro antiherpetic action at 1 mg/ml, FR-S displayed promising anti-HSV-1 and anti-HSV-2 activities in both simultaneous and postinfection treatments, resulting in selectivity indices (CC₅₀/EC₅₀) higher than 393. FR-S had no virucidal effect, but significantly suppressed HSV-1 (EC₅₀ = 0.32 µg/ml) and HSV-2 (EC₅₀ = 0.10 µg/ml) adsorption. FR-S was less effective on adsorption inhibition of mutant virus strains devoid of gC (HSV-1 gC⁻39 and HSV-2 gCneg1), indicating a possible interaction with this glycoprotein. The reduction of viral adsorption upon cell pretreatment with FR-S also suggests its interaction with cellular components. FR-S inhibited HSV-1 (EC₅₀ = 8.39 µg/ml) and HSV-2 (EC₅₀ = 2.86 µg/ml) penetration more efficiently than heparin. FR-S reduced HSV-1 and HSV-2 cell-to-cell spread. A synergic effect between FR-S and acyclovir was also detected.

CONCLUSIONS

FR-S displays an interesting mechanism of antiviral action and represents a promising candidate for the treatment and/or prevention of herpetic infections, to be used as a single therapeutic agent or in combination with acyclovir.

Biological activities of derivatized D-glucans: a review

D-Glucans have triggered increasing interest in commercial applications in the chemical and pharmaceutical sectors because of their technological properties and biological activities. The glucans are foremost among the polysaccharide groups produced by microorganisms with demonstrated activity in stimulating the immune system, and have potential in treating human disease conditions. Chemical alterations in the structure of D-glucans through derivatization (sulfonylation, carboxymethylation, phosphorylation, acetylation) contributes to their increased solubility that, in turn, can alter their biological activities such as antioxidation and anticoagulation. This review surveys and cites the latest advances on the biological and technological potential of D-glucans following chemical modifications through sulfonylation, carboxymethylation, phosphorylation or acetylation, and discusses the findings of their activities. Several studies suggest that chemically modified d-glucans have potentiated biological activity as anticoagulants, antitumors, antioxidants, and antivirals. This review shows that in-depth future studies on chemically modified glucans with amplified biological effects will be relevant in the biotechnological field because of their potential to prevent and treat numerous human disease conditions and their clinical complications.

Sulfated Astragalus polysaccharide can regulate the inflammatory reaction induced by LPS in Caco2 cells

This study evaluates the effect of sulfated Astragalus polysaccharide (SAPS) on inflammatory reaction induced by LPS in Caco2 cells. Sulfated modification was conducted using the chlorosulfonic acid-pyridine method. Caco2 cells were cultured with 25, 50 and 100 μg/mL SAPS or 100 μg/mL Astragalus polysaccharide (APS) for 24 h. Then, 1 μg/mL LPS was added for the next 24 h to trigger an inflammatory response. DMEM culture medium was used as a blank control. In present study, LPS stimulation significantly increased the mRNA expression of TNF-α, IL-1β, IL-8 and TLR4, and reduced the expression of ZO-1 and occludin. Compared with the LPS control group, APS (100 μg/mL) or SAPS (100 μg/mL) administration decreased the expression of TNF-α, IL-1β and IL-8. Moreover, 25 μg/mL and 50 μg/mL SAPS down-regulated TNF-α and IL-1β expression. APS administration (100 μg/mL) up-regulated occludin expression, but did not affect ZO-1 expression. However, the expression of ZO-1 and occludin was up-regulated by lower dose SAPS administration (25 μg/mL and 50 μg/mL). Compared with the other groups, the expression of TLR4 was lower in the SAPS group at all concentrations of SAPS. These results suggest that SAPS was to be a more effective anti-inflammatory agent than APS in vitro.

A New Homoisoflavanone from the Rhizomes of Polygonatum cyrtonema

A new homoisoflavanone, (3 R)-5,7-dihydroxy-8-methyl-3-(2′-hydroxy-4′-methoxybenzyl)-chroman-4-one (1), was isolated from the 95% ethanol extract of the rhizomes of Polygonatum cyrtonema. The structure of 1 was determined by spectroscopic methods, especially 2D NMR techniques. Quantum chemical TD DFT calculations of the theoretical ECD spectrum of 1 allowed assignment of the absolute configuration as 3R.