Induction of Apoptosis in Human Hepatoma SMMC-7721 Cells by Polysaccharides from <em>Lycium barbarum</em> L.

Lycium barbarum L, a traditional Chinese herb rich in functional components such as polysaccharide, has been widely consumed in Asian countries. The purpose of this study was to evaluate the inhibitory effect of Lycium barbarum Polysaccharide (LBP2) on human hepatoma SMMC-7721 cells and investigate the possible mechanism of apoptosis. An acidic polysaccharide LBP2 isolated from the fruit of Lycium barbarum L. was purified by ion-exchanged column. Chemical analysis indicated LBP2 was composed of three kinds of monosaccharides including mannose, galactose and glucose with the molar ratios of 1.32, 1.79 and 7.38 with average molecular weight of 358 kDa, and consisted of neutral sugars, uronic acid and protein. SMMC-7721 cell viability was assessed by MTT assay. The effect on morphology was observed with a inverted microscopy. The cell cycle was analyzed by flow cytometry. GJIC was measured using laser scanning confocal microscopy. LBP2 significantly inhibited the growth of SMMC-7721 cells and induced cell apoptosis. Cell cycle analysis revealed that LBP2 caused cell cycle arrest at the G0/G1 phase. Moreover, induction of apoptosis was associated with an increase in GJIC. The study demonstrated that LBP2 has a potential for inducing apoptosis and promoting GJIC.