This study focuses on the acetylation modification of polysaccharides from Rhododendron dauricum leaves (RDPs) with a high degree of substitution (DS) and then discusses their characterization and biological activity. The optimum acetylation conditions of RDPs were optimized by response surface methodology, which were reaction time 3 h, reaction temperature 50 °C, and the liquid-solid ratio 16 mL/g. Under the optima schemes, two eco-friendly acetylated polysaccharides from R. dauricum leaves (AcRDP-1 with DS of 0.439 ± 0.025 and AcRDP-2 with DS of 0.445 ± 0.022) were prepared. The results of structural characterization showed that the AcRDP-1 (9.3525 × 103 kDa) and AcRDP-2 (4.7016 × 103 kDa) were composed of mannose, glucose, galactose, and arabinose with molar ratios of 1.00:5.01:1.17:0.15 and 1.00:4.47:2.39:0.88, respectively. Compared with unmodified polysaccharides, the arabinose content and molecular weight of the two acetylated polysaccharides decreased, and their triple helix conformation disappeared, and further improved their anticomplementary activity. The two acetylated polysaccharides showed stronger a complement inhibition effect than the positive drug by blocking C2, C3, C4, C5, C9, and factor B targets in the classical and alternative pathways. This research indicated that acetylation modification could effectively enhance the anticomplementary activity of RDPs, which is beneficial for the development and utilization of R. dauricum leaves.
This investigation focuses on the three novel polysaccharides from Cordyceps militaris and then discusses their characterization and anti-complementary activity. The three polysaccharides from C. militaris (CMP-1, CMP-2 and CMP-3) were prepared using a DEAE-52 cellulose column. The HPLC, HPGPC, FT-IR and Congo red analyses were used to characterize their monosaccharides, molecular weight and stereo conformation, which demonstrated that the three polysaccharides were homogenous polysaccharides with different molecular weights and were composed of at least ten monosaccharides with different molar ratios, and all had a triple-helix conformation. The evaluation of anti-complementary activity demonstrated that the three polysaccharides significantly inhibited complement activation through the classical pathway and alternative pathway. Preliminary mechanism studies indicated that CMP-1, CMP-2 and CMP-3 acted with C2, C5, C9, factor B, factor B, and P components in the overactivation cascade of the complement system. The analysis of the Pearson correlation and network confirmed that the ribose, glucuronic acid and galacturonic acid composition were negatively correlated with the anti-complementary activity of polysaccharides. These results suggested that the three novel polysaccharides are potential candidates for anti-complementary drugs.
The polysaccharides from the rhizomes of Belamcanda chinensis (L.) DC. (BCPs) were obtained by optimal water extraction (extraction temperature 84 °C, liquid to solid ratio 42 mL/g and extraction time 100 min), the extraction yield of BCPs was 23.01 � 0.27 % (n = 3). Furthermore, two novel polysaccharides (BCP-A1 and BCP-B1) were purified by column chromatography. The BCP-A1 (6.0820 × 10 4 kDa) was composed ofIn anticomplementary experiments, BCP-A1 (CH 50 : 0.009 � 0.003 mg/mL; AP 50 : 0.015 � 0.003 mg/mL) and BCP-B1 (CH 50 : 0.004 � 0.001 mg/mL; AP 50 : 0.028 � 0.005 mg/mL) exhibited potent anticomplementary activity, and acted on C2-, C4-and Factor B components. Our study provides a foundation for BCP-A1 and BCP-B1 as potential complement inhibitors to treat diseases involving with excessive activation of the complement system.
The two novel polysaccharides, DMP‐1 and DMP‐2, with molecular weights of 4.1553×105 kDa and 1.9764×105 kDa, respectively, were isolated from Dracocephalum moldavica. The structural characterization indicated that DMP‐1 and DMP‐2 shared a similar backbone consisting of →5)‐Araf‐(1→, Manp‐(1→, Glcp‐(1→, →2)‐Manp‐(1→, →6)‐Glcp‐(1→ and →3,6)‐Galp‐(1→ with a different molar ratios and triple‐helix structures with α‐ and β‐type glycosidic bonds. The anti‐complementary activity evaluation showed that DMP‐1 and DMP‐2 had strong complement inhibition through the classical pathway (CP), alternative pathway (AP) and lectin pathway (LP). Mechanistic studies indicated that DMP‐1 can block the activation cascade of the complement system by targeting C2, C3, C5, C9, Factor B and Factor P, and that DMP‐2 inhibited complement activation by blocking C2, C3, C4, C5, C9 and Factor B.
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