Preparation, purification and cardiac protective effect of a pectin-like polysaccharide from red ginseng

Ginseng polysaccharides have exhibited a broad range of pharmacological effects that are beneficial to the human health. This study was designed to prepare purified polysaccharides from red ginseng (the steamed product of Panax ginseng). Total polysaccharides of red ginseng (PRG) were obtained via a series of extraction procedures, involving the ultrasound-assisted extraction, ethanol precipitation, and deproteinization using the Sevag reagent, and the yield of PRG was 13.32 %. Subsequent hydrolysis with α-amylase was conducted, followed by the fractionation on a DEAE-cellulose (OH^- form) column. Elution with a stepwise NaCl gradient, purification through the dialysis, and desalting gave the purified polysaccharide, namely RG0203. Structural characterization by chromatography and nuclear magnetic resonance spectroscopy (NMR) analysis could confirm that, RG0203 as a homogalacturonan-rich pectic polysaccharide, primarily comprising a backbone of α(1 → 4)-linked GalpA residues with 33.03 % methyl esterification, interspersed with neutral sugars including L-Arabinose (Ara), D-Galactose (Gal), d-Glucose (Glc), L-Rhamnose (Rha), and L-Fucose (Fuc). Cellular assays and an ex vivo myocardial ischemia model evaluation demonstrated a promising improvement effect of RG0203 in the cardiac function. At 50 μg/mL, RG0203 significantly attenuated Oxygen and Glucose Deprivation (OGD)- and hydrogen peroxide (H₂O₂)-induced inflammatory injury in the cardiomyocytes. At 200 μg/mL, it could elevate left ventricular pressure changes in rats with acute myocardial ischemic injury. Conclusively, the prepared polysaccharide RG0203 exhibits potential cardioprotective efficacy against acute myocardial ischemia.