Extraction, purification and antitumor activity of a water-soluble polysaccharide from the roots of Polygala tenuifolia

► A polysaccharide (PTP) was isolated from the roots of Polygala tenuifolia. ► PTP was effective on inhibiting the proliferation of SKOV3 cells in a concentration-dependent manner. ► PTP caused a rapid depletion of intracellular GSH in SKOV3 cells. ► PTP caused the accumulation of intracellular ROS in SKOV3 cells. ► PTP administration could significantly inhibit tumor growth in nude mice.