Structural Characterization and Anti-Proliferation Activities Against Tumor Cells of an Arabinogalactan from Juniperus convallium

As a hyperproliferative disorder, cancer has continued to be a major public health challenge. In the present study, a polysaccharide JC-PS1 was isolated and purified from Juniperus convallium. JC-PS1 is a heteropolysaccharide composed of Ara, Gal, GalA and Rha with the average molecular weight of 280 kDa. Based on the methylation and 2D NMR analysis, JC-PS1 was elucidated as a backbone of →5)-α-Araf-(1→ and →3,5)-α-Araf-(1→, and three kinds of branches attached to the O-3 position of →3,5)-α-Araf-(1→, including β-GalpA-(1→3)-β-Galp-(1→, α-Araf-(1→3)-α-Rhap-(1→ and α-Araf-(1→3)-β-Galp-(1→. Accordingly, the atomic force microscopy of JC-PS1 showed a linear filamentous structure with small proportion of branches. Furthermore, JC-PS1 exhibited significant anti-proliferation activities against PANC-1, A431, MDA-MB-231, U118MG and H1975 cells with the IC₅₀ values of 296.8, 477.9, 657.4, 686.7 and 862.1 μg/mL, respectively. This indicated that JC-PS1 could be a potential therapeutic agent for the treatment of cancer.