Immunostimulating and Anticancer Activities of the Pectic Polysaccharide from <i>Panax ginseng</i> Leaves Treated with High Pressure/Enzyme Process

This study was designed to investigate the immunostimulatory and anticancer efficacies of pectic polysaccharides from ginseng leaves treated using the high-pressure extraction method (HPEM). The isolation of polysaccharides using HPEM resulted in 1.35-fold higher polysaccharide yields than those obtained using the commonly used hot water extraction method. In addition, component sugar analysis of ginseng-leaf-derived polysaccharides (GLHP) showed the presence of nine different types of monosaccharides, including galacturonic acid, galactose, rhamnose, and arabinose, which are characteristic of pectic polysaccharides. In addition, GLHP effectively induced activation of the complement system, and macrophages stimulated with GLHP showed enhanced production of cytokines such as IL-6, IL-12, and TNF-α. Intravenous (i.v.) and oral administration (p.o.) of GLHP significantly increased the cancer-cell-killing ability of spleen-derived NK cells. In a lung-cancer-bearing mouse model using Colon26-M3.1 carcinoma, prophylactic i.v. and p.o. GLHP potently inhibited 95.2% and 33.5% of lung cancer, respectively. Furthermore, GLHP showed significant anticancer effects, even in mice with NK cell dysfunction, via the anti-asialo GM1 antibody. These effects may be related to the cancer-cell-killing effects of cytotoxic T lymphocytes (CTL). Therefore, GLHP, a polysaccharide isolated from ginseng leaves using HPEM, has a potent anticancer effect, and these effects are closely related to the stimulation of various immune factors.