Swallow root (Decalepis hamiltonii) pectic oligosaccharide (SRO1) induces cancer cell death via modulation of galectin-3 and survivin

Swallow root pectic oligosaccharide fraction (SRO1) from swallow root pectic polysaccharide (SRPP) possessed a molecular size of 831 Da. Structural analysis revealed that it is a rhamnogalacturonan I type, bearing arabinogalactan side chain with β-d-(1→4) galactose along with α-l-Araf (1→5)-α-l-Araf (1→3) structure on α-d-GalA-OAc-(1→2)-α-l-Rha-(1→4)- linear backbone. β-d (1→4) linked galactose being the specific sugar for galectin-3, SRO1 had potentials in inhibiting galectin-3 mediated cancer progression. SRO1 inhibited galectin-3 mediated agglutination, in vitro, effectively with MIC of 1.08 μg/ mL and down regulated mRNA levels of galectin-3 (∼92%) along with its downstream key protein that inhibits apoptosis - survivin (∼78%) suggesting the capability of SRO1 in inhibiting galectin-3 mediated cancer promoting pathway. This is the first report, which highlights the inhibition of interplay of galectin-3 and survivin by a dietary pectic oligosaccharide.