Catalytic synthesis of sulfated polysaccharides. II: comparative studies of solution conformation and antioxidant activities.
Sulfated derivatives of Artemisia sphaerocephala polysaccharide (ASP) with high degree of substitution (DS) were synthesized using 4-dimethylaminopyridine (DMAP)/dimethylcyclohexylcarbodiimide (DCC) as catalyst. Size exclusion chromatography combined with multi-angle laser light scattering (SEC-LLS) results showed a decrease in fractal dimension (df) values of sulfated ASP (SASP). Compared to ASP and SASP with low DS (0.51-1.01), SASPcata2 exhibited an internal structure between rigid rod and random coil with a DS of 1.24. DS had greater influence on its conformation in aqueous solution. Circular dichroism (CD), methylene blue (MB) and Congo red (CR) spectrophotometric method and atomic force microscopy (AFM) results confirmed that the degradation of ASP and SO3H groups improved significantly the stiffness of the chains due to the electrostatic effect. Furthermore, antioxidant experiments revealed that high DS could enhance the scavenging activities of radicals and reducing power of SASP in vitro. The extended chain conformation was beneficial to enhance the biological activity of sulfated polysaccharides.
College of Life Science, Northwest Normal University, Lanzhou 730070, China; Bioactive Products Engineering Research Center for Gansu Distinctive Plants, Lanzhou 730070, China. Electronic address: nuno-vai@163.com.
Junlong
J
Wang
College of Life Science, Northwest Normal University, Lanzhou 730070, China.
Shengfan
S
Niu
College of Life Science, Northwest Normal University, Lanzhou 730070, China; Bioactive Products Engineering Research Center for Gansu Distinctive Plants, Lanzhou 730070, China.
Baotang
B
Zhao
College of Life Science, Northwest Normal University, Lanzhou 730070, China.
Tian
T
Luo
College of Life Science, Northwest Normal University, Lanzhou 730070, China.
Die
D
Liu
College of Life Science, Northwest Normal University, Lanzhou 730070, China; Bioactive Products Engineering Research Center for Gansu Distinctive Plants, Lanzhou 730070, China.
Ji
J
Zhang
D002236:Carbohydrate Conformation; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D016166:Free Radical Scavengers / Q000138:chemical synthesis* / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D008970:Molecular Weight; D011134:Polysaccharides / Q000138:chemical synthesis* / Q000737:chemistry*; D012996:Solutions; D013329:Structure-Activity Relationship; D013431:Sulfates / Q000737:chemistry*
D016166:Free Radical Scavengers; D005609:Free Radicals; D011134:Polysaccharides; D012996:Solutions; D013431:Sulfates
Antioxidant activities; Artemisia sphaerocephala; Catalytic synthesis; Solution conformation; Sulfated polysaccharides