Wuxia Zhang

Extraction optimization, characterization and immunity activity of polysaccharides from Fructus Jujubae.

The versatile Fructus Jujubae is widely used in Chinese and Korean traditional medicine. In this study, the extraction optimization, characterization and immunostimulatory activities of polysaccharides from Fructus Jujubae were investigated. Based on a four-variable-three-level Box-Behnken statistical design, the optimal extraction parameters were optimized as follows: extraction temperature 90 °C, extraction time 3.23 h, water to raw material ratio 33:1 and extraction 3 times. Under these conditions, the experimental yield of polysaccharides was 6.47 ± 0.26%, which was close to the predicted yield value (6.54%). The crude Fructus Jujubae polysaccharide was further purified by DEAE-cellulose chromatography repeatedly, and two homogenous fractions, designated as RQP1d and RQP2d with molecular weight of 83.8 and 123.0 kDa respectively, were obtained. Their structures were determined by chemical analysis, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Finally, preliminary immunological tests indicated that both RQP1d and RQP2d significantly stimulated NO production in RAW264.7 macrophages, and promoted LPS-induced splenocyte proliferation. These data implied Fructus Jujubae polysaccharides had the potential to be explored as novel natural immunostimulant for using in functional foods or medicine.

Characterization of polysaccharides with antioxidant and immunological activities from Rhizoma Acori Tatarinowii

Rhizoma Acori Tatarinowii is widely used in traditional Chinese medicine. In this study, three novel polysaccharides designated RATPW, RATPS1 and RATPS2 were isolated from Rhizoma Acori Tatarinowii by DEAE-52 cellulose chromatography. Their structures were characterized using physicochemical and spectral methods. Chemical analysis indicated that RATPW (6.5×10(3)Da) mainly composed of glucose and fructose. RATPS1 (1.5×10(5)Da) contained galactose and arabinose, while RATPS2 (5.3×10(4)Da) contained ∼49.5% galacturonic acid along with rhamnose, fructose, galactose, and arabinose. In vitro, RATPS2 showed the most significant scavenging activity on DPPH and hydroxyl radical. Three polysaccharides could protect the PC12 cells from H2O2-induced damage. Immunological tests indicated that both RATPW and RATPS2 significantly stimulated NO production and phagocytic activity in RAW264.7, and promoted splenocyte proliferation. These data suggested that polysaccharides RATPW and RATPS2 had the potential as novel natural sources of antioxidative and immunopotentiating agents.

Novel pH-sensitive polysialic acid based polymeric micelles for triggered intracellular release of hydrophobic drug.

Polysialic acid (PSA), a non-immunogenic and biodegradable natural polymer, is prone to hydrolysis under endo-lysosomal pH conditions. Here, we synthesized an intracellular pH-sensitive polysialic acid-ursolic acid conjugate by a condensation reaction. To further test the drug loading capability, we prepared paclitaxel-loaded polysialic acid-based amphiphilic copolymer micelle (PTX-loaded-PSAU) by a nanoprecipitation method. Results showed PTX-loaded-PSAU exhibited well-defined spherical shape and homogeneous distribution. The drug-loading was 4.5% with an entrapment efficiency of 67.5%. PTX released from PTX-loaded-PSAU was 15% and 42% in 72 h under simulated physiological condition (pH 7.4) and mild acidic conditions (pH 5.0), respectively. In addition, In vitro cytotoxicity assay showed that PTX-loaded-PSAU retained anti-tumor (SGC-7901) activity with a cell viability of 53.8% following 72 h incubation, indicating PTX-loaded-PSAU could efficiently release PTX into the tumor cells. These results indicated that the pH-responsive biodegradable PTX-loaded-PSAU possess superior extracellular stability and intracellular drug release ability.

Homogalacturonans from Preinfused Green Tea: Structural Characterization and Anticomplementary Activity of Their Sulfated Derivatives

Two homogeneous water-soluble polysaccharides (TPSR4-2B and TPSR4-2C) were obtained from preinfused green tea. Their average molecular weights were estimated to be 41 kDa and 28 kDa, respectively. A combination of composition, methylation, and configuration analysis, as well as NMR spectroscopy, indicated that both TPSR4-2B and TPSR4-2C were poly-(1-4)-α-d-galactopyranosyluronic acid in which 30.5 ± 0.3% and 28.3 ± 0.5%, respectively, of uronic acid existed as methyl ester. Two sulfated derivatives (Sul-R4-2B and Sul-R4-2C) from TPSR4-2B and TPSR4-2C were prepared after sulfation with a 2:1 chlorosulfonic acid-pyridine ratio. The anticomplementary assay showed that Sul-R4-2B and Sul-R4-2C demonstrated a stronger inhibitory effect on the complement activation through the classic pathway, compared to that of heparin. Preliminary mechanism studies by using complement component depleted-sera indicated that both Sul-R4-2B and Sul-R4-2C selectively interact with C1q, C1r, C1s, C2, C5, and C9 but not with C3 and C4. The relationship between DS and the anticomplementary activity of sulfated derivatives of homogalacturonans showed that low sulfated derivatives of homogalacturonans also exhibited potent anticomplementary effect, which might greatly reduce the side effects related to heparin and oversulfated chondroitin sulfate, such as anticoagulant activity and allergic-type reaction. These results suggested that sulfated derivatives of homogalacturonans might be promising drug candidates for therapeutic complement inhibition.

Variation in antioxidant activities of polysaccharides from Fructus Jujubae in South Xinjiang area.

The Fructus Jujubae has been widely used as favorable food and folk medicine in China and Russia. In this study, we compared the carbohydrate constituents and antioxidative effects of Fructus Jujubae polysaccharides from five different production areas in South Xinjiang. Results demonstrated that the average annual temperature (r=0.590) and frost-free period (r=0.779) were well correlated to the uronic acid content, while the neutral carbohydrate content showed negative correlation with precipitation amount (r=-0.567). Antioxidative tests indicated that Fructus Jujubae polysaccharides could scavenge chemicals-induced reactive oxygen species in a dose-dependent manner. In addition, these polysaccharides could rescue H₂O₂-induced HUVEC death. The antioxidative activity of polysaccharides from the Fructus Jujubae might contribute to their diverse medicinal and nutritional values.

Investigation of three lignin complexes with antioxidant and immunological capacities from Inonotus obliquus

Mushroom Inonotus obliquus (I. obliquus), a folk medicine, has been widely used to treat several human malicious tumors since 16th century. In this study, three homogenous biomolecules (designated IOA1, IOA2 and IOA3) were prepared from the alkali extract of I. obliquus. Their molecular weights were measured to be 6.1 × 10(4), 2.9 × 10(4) and 3.5 × 10(4) g/mol respectively and all of them were characterized as lignin-carbohydrate complexes mainly comprised lignin as well as -25% carbohydrates. Antioxidant assays indicated that all of them exhibited pronounced reductive power and strong scavenging activities on DPPH and hydroxyl radicals in vitro. Immunological tests showed that they could also significantly stimulate nitric oxide production and phagocytic activity in RAW 264.7 macrophages. These results implied that the lignin-carbohydrate complexes extracted from I. obliquus might be used as novel natural antioxidants or immunostimulants in functional foods or pharmaceutical candidates.

Characterization of two water-soluble lignin metabolites with antiproliferative activities from Inonotus obliquus.

The chaga mushroom, Inonotus obliquus has long been recognized as a remedy for cancer, gastritis, ulcers, and tuberculosis of the bones since the 16th century. Herein we reported the identification of two homogenous biological macromolecules, designated as IOW-S-1 and IOW-S-2 with anti-tumor activities from the hot-water extract of I. obliquus. Their molecular weights were determined to be 37.9 and 24.5kDa by high performance gel permeation chromatography (HPGPC) respectively. Chemical and spectral analysis indicated that both IOW-S-1 and IOW-S-2 were predominant in lignin, along with ∼20% carbohydrates. Examination of cytotoxicity showed that these two lignin-carbohydrate complexes induced cell death in a concentration dependent manner, while this apoptosis induction was largely cell-cycle independent. Further investigation demonstrated that IOW-S-1 or IOW-S-2 inhibited the activation of the nuclear transcription factor in cancer cells. These findings implied that soluble lignin derivatives were one of bioactive components in I. obliquus, and further provided insights into the understanding of molecular basis for diverse medicinal and nutritional values of this mushroom.

Alteration in immune responses toward N-deacetylation of hyaluronic acid

Hyaluronic acid (HA) is an ubiquitous nonsulfated glycosaminoglycan of the extracellular matrix in all mammalian connective tissues. Along with the age growth, HA will lose its N-acetyl groups in vivo; however, the significance of this physiological process remains largely unknown. Herein, three highly N-deacetylated HAs (dHAs), dHA-5 kDa (Mw: 5 kDa, DD: 100%), dHA-16 kDa (Mw: 16 kDa, DD: 94%) and dHA-110 kDa (Mw: 110 kDa, DD: 72%), were generated after hydrazinolysis. Their capability in the activation of antigen-presenting cells (APCs) was compared with that of their respective HAs. Our results demonstrated that both HAs and dHAs could activate the nuclear factor-kappa B (NF-κB) transcription factor in APCs and induced cytokine production through the Toll-like receptor (TLR)/MyD88 pathway. Notably, the capacity of dHAs in cytokine induction was much lower than that of HAs. In addition, the TLR-2 pathway was much involved following the appearance of zwitterionic motifs in dHAs. Thus, our findings highlight that N-deacetylation renders HA divergences in immune response, which might be implicated in age-induced functional change in endogenous glycosaminoglycans due to the structural modification in vivo.

Preparation and sulfation of an α-glucan from Actinidia chinensis roots and their potential activities

In this study, one homopolysaccharide (ACPA1) with a molecular weight (Mw) of 5.5×103g/mol was prepared from the roots of Actinidia chinensis. It was characterized as an α-d-glucan consisting of predominant 4-linked α-d-Glcp residues branched at O-6. Three sulfated derivatives of ACPA1 (SA1, SA2 and SA3) with different degrees of sulfation (DS) were obtained by SO3-pyridine procedure. Moisture-preserving tests demonstrated that the sulfated derivatives with the highest DS values, SA1 and SA2, exhibited better moisture-preserving abilities than ACPA1 and SA3. All sulfated derivatives exerted stimulatory effects on phagocytosis activity and nitric oxide production by RAW 264.7 macrophages while ACPA1 did not. These findings suggested that the sulfated derivatives of ACPA1 might be used as moisture-preserving or immunopotentiating reagents.

Mechanistic insights into cellular immunity of chondroitin sulfate A and its zwitterionic N-deacetylated derivatives.

As a major component in extracellular matrix of the tissue, chondroitin sulfate A (CS-A) has been shown to exhibit either pro- or anti-inflammatory immune response which was largely dependent on its molecular size and cell types. In this study, we determined the signaling pathway involved in immune response of CS and its N-deacetylated derivative (dCS). Our data indicated that both CS and dCS could activate the NF-κB transcription factor in antigen presenting cells and induce TNF-α production through the TLR/MyD88 pathway. Further studies demonstrated that both CS and dCS had a potential in promoting the proliferation of spleen lymphocytes, and promoting the cytokines secretion by OVA-sensitized splenocytes. Thus, our finding provided a mechanistic insight into the understanding of cellular immunity of CS and dCS, which might be helpful to develop CS-based immune modulators against chronic inflammatory conditions, autoimmunity, infectious diseases, allergies and asthmatic conditions.