Physicochemical properties of polysaccharides from Ligusticum chuanxiong and analysis of their anti-tumor potential through immunoregulation

Abstract

We investigated the extraction, purification, physicochemical properties and biological activity of Ligusticum chuanxiong polysaccharides (LCXPs). Two polysaccharide fractions (Ligusticum chuanxiong [LCX]P-1a and LCXP-3a) were obtained by DEAE Sepharose™ Fast Flow and Sephacryl™S-300 high resolution column chromatography. The results showed that the molecular weight of LCXP-1a and LCXP-3a was 11.159 kDa and 203.486 kDa, respectively. LCXP-1a is composed of rhamnose, glucuronic acid, galacturonic acid, and glucose at a molar percentage of 0.52 : 1.88 : 1.06 : 95.36, But LCXP-3a has another molar percentage of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose, arabinose, and fucose of 0.64 : 6.69 : 1.03 : 43.74 : 2.20 : 26.90 : 0.82 : 15.94 : 1.80. Both LCXP-1a and LCXP-3a could stimulate macrophages to produce NO, TNF-α, IL-6, and IL-12p70. Co-culturing macrophages and hepatocellular carcinoma cells showed that LCXP-1a and LCXP-3a inhibited the growth of HepG2 and Hep3B through immunoregulation. They arrested the cell cycle at the G0/G1 phase and promoted apoptosis. Moreover, there was no cytotoxicity to the hepatocyte cell line, LO2. We also noted that the immunomodulatory activity and anti–tumor activity of LCXP-3a were significantly better than those of LCXP-1a. Our data demonstrate that LCXP-3a is potentially a well-tolerated and effective immunomodulatory adjuvant cancer treatment.