Structural characterization and in vitro antitumor activity of A polysaccharide from Artemisia annua L. (Huang Huahao)

One water-soluble polysaccharide (AAP), with a molecular weight of 6.3x104 Da, was isolated from Artemisia annua L. Structrual analysis indicated that AAP was found to be a 1, 3-alpha-linked and 1, 3, 6-alpha-linked Glcp backbone, with a branch of 1, 6-alpha-linked Glcp and terminal 1-linked-L-Rhap along the main chain in a ratio of 1: 1: 1: 1. MTT assay showed that AAP reduced the cell viability of HepG2 cells in a concentration-dependent manner. DAPI staining and Flow cytometric analysis revealed that AAP suppressed cells proliferation, not most at least via inducing p65-dependent mitochondrial signaling pathway, as evidenced by more activation of caspase-3 and -9, down-regulation of Bcl-2 protein, up-regulation of Bax protein and release of cytochrome c from mitochondria into cytosol, as well as suppression of the nuclear factor-kappa B (NF-kappa B) p65. These data confirmed AAP inhibits HepG2 cell growth via inducing caspase-dependent mitochondrial apoptosis and inhibition of NF-kappa B p65.