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Anticancer Effect of Lycium Barbarum Polysaccharides on Colon Cancer Cells Involves G0/G1 Phase Arrest

Goji berries (Lycium barbarum, wolfberry) grow on an evergreen shrub found in temperate and subtropical regions in China, Mongolia and in the Himalayas in Tibet. They are in the nightshade (Solonaceae) family. Goji berries are usually found dried. They are shriveled red berries that look like red raisins. Goji berries are rich in antioxidants, particularly carotenoids such as Beta-carotene and zeaxanthin. One of zeaxanthin's key roles is to protect the retina of the eye by absorbing blue light and acting as an antioxidant. Goji berries have been used for 6,000 years by herbalists in China, Tibet and India to: protect the liver, help eyesight, improve sexual function and fertility, strengthen the legs, boost immune function, improve circulation, and to promote longevity.

Mao F, Xiao B, Jiang Z, Zhao J, Huang X, Guo J. Anticancer effect of Lycium barbarum polysaccharides on colon cancer cells involves G0/G1 phase arrest. 1. Med Oncol. 2011 Mar;28(1):121-6. Epub 2010 Jan 12.

Colorectal cancer is one of the most common cancers worldwide. The anticancer effect of wolfberry (Lycium barbarum) polysaccharide (LBP) on colon cancer cells is largely unknown. To investigate the growth effect of LBP on human colon cancer cell and its possible mechanisms, human colon cancer SW480 and Caco-2 cells were treated with 100-1,000 mg/l LBP for 1-8 days. Cell growth was measured by MTT assay and crystal violet assay. Distribution of the cell cycle was analyzed by flow cytometry. Western blotting was used to indicate changes in the level of cyclins and cyclin-dependent kinases (CDKs). LBP treatment inhibited both colon cancer cell lines in a dose-dependent manner. At concentrations from 400 to 1,000 mg/l, LBP significantly inhibited the growth of SW480 cells (400 mg/l, P < 0.01; 800 and 1,000 mg/l, P < 0.001); while at concentrations from 200 to 1,000 mg/l, LBP significantly inhibited the growth of Caco-2 cells (200 mg/l, P < 0.05; 400-1,000 mg/l, P < 0.001). Crystal violet assay showed that LBP had a long-term anti-proliferative effect. More importantly, cells were arrested at the G0/G1 phase. The changes in cell-cycle-associated protein, cyclins, and CDKs were consistent with the changes in cell-cycle distribution. This is one of the first studies to focus on LBP-induced interruption of the cell cycle in human colon carcinoma cells. The results suggest that LBP is a candidate anticancer agent.