Purification, Characterization, and Anticomplementary Activity of Polysaccharides From the Fruits of Amomum tsaoko Crevost & Lemarié

The resin purification condition of polysaccharides from Amomum tsaoko Crevost et Lemarie (ATPs) was optimized using response surface method (RSM) and analytic hierarchy process (AHP): elution volume of 2 BV, flow rate of 2 BV/h, sample concentration of 2 mg/mL, sample volume of 0.4 BV, the comprehensive score of actual purification effect was 73.45 ± 0.32% (n = 3). Then, a homogenous polysaccharide (ATP-1-1) was isolated by DEAE-52 cellulose and Sephadex G-200 column. The structure of ATP-1-1 was characterized by the Fourier transform infrared spectroscopy, high-performance liquid chromatography, high-performance gel permeation chromatography, Congo red test, scanning electron microscopy, and thermogravimetric analysis, which showed that ATP-1-1 was composed of mannose, rhamnose, glucose, galactose, and arabinose in a molar ratio of 1.3:1.0:6.2:4.8:1.1 with molecular weight of 845.21 kDa, and had a triple-helix conformation, blocky microstructure, and good thermal stability. The evaluation of anti-complementary activity showed that ATP-1-1 possessed stronger anticomplementary activity than positive drug, significantly inhibited complement activation through both classical (CH 50 = 6.28 ± 0.23 μg/mL) and alternative pathways (AP 50 = 45.33 ± 0.16 μg/mL), and interacted with C2, C4, and factor B components in the activation cascade of the complement system.