Isolation, characterization and anti-inflammatory activity of pectin from common pondweed Potamogeton natans L

The pectic polysaccharide named potamogetonan PN was obtained using extraction of the floating leaf of the aquatic plant P. natans L. (Potamogetanaceae) by 0.7% aqueous ammonium oxalate and subsequent precipitation with ethanol. The polysaccharide obtained (yield 4%) proved to compose mainly of D-galacturonic acid (82%) mainly altogether with the minor residues of galactose (1.7%), rhamnose (0.8%), arabinose (1.4%) and glucose (1.1%). Potamogetonan PN was shown to contain sugar chains of molecular weights more than 300 kDa (78%) as proved by membrane ultrafiltration.

Anti-inflammatory capacity of potamogetonan was assessed in the carrageenan paw edema test in mice. Oral administration of PN 24h prior to induction of inflammation was found to reduce the edema formation in a dose-related manner. The maximal effect of PN (50mg/kg) was observed at 1h after carrageenan injection (80% reduction of footpad swelling) and was comparable with that of indomethacin (50mg/kg, p.o.) The delayed edema (5h) was less affected by the preadministration of PN (33% reduction). Potamogetonan was shown to inhibit spontaneous and phorbol-12-myristate-13-acetate-activated adhesion of peritoneal leukocytes in vitro.

Thus, pectin (potamogetonan PN) was isolated from P.natans and was found to possess strong preventive anti-inflammatory activity especially in relation to initial phase of inflammation development.