Sulfation of citrus pectin by pyridine-sulfurtrioxide complex and its anticoagulant activity

• We first use the pyridine sulfurtrioxide complex-DMSO system to prepare the sulfated CP.
• The sulfation was mainly occurred in the C-2 and C-3 position of the GalA.
• Sulfated CP showed high potency in prolonging APTT, TT.
• Sulfated CP inhibited the activation of the thrombin mainly by HC II.
• The sulfated CP with high content of GalA could be easily quality-controlled.

Citrus pectin (CP) was sulfated by the pyridine–sulfur-trioxide complex in dimethyl sulfoxide (DMSO). Monosaccharide composition analysis revealed a decrease in the GalA content after sulfation. A decrease in the average molecular weight (MW) and a fall in particle size of the pectin gave additional proof of pectin degradation during the sulfation reaction. Structural characterization by IR and NMR spectra indicated sulfation occurred mainly at positions C-2, C-3 of the GalA (located in backbone region of the CP). Anticoagulant assays demonstrated that sulfated CP (TBA-3) could prolong activated partial thromboplastin time and thrombin time, with an activity of 51.96 IU/mg and 15.2 IU/mg, respectively. Further investigation on coagulation factors indicated TBA-3 could achieve inactivation of thrombin with both heparin cofactor II and antithrombin. Our results indicated sulfated pectin might be a promising anticoagulant ingredient with excellent activity and simple monosaccharides, and could be a possible substitute for the limited heparin.