Orostachys cartilaginous is a traditional herbal medicine and its cell cultures contain large amounts of polysaccharides. To utilize the cultured O. cartilaginous cells, this study purified the crude polysaccharides of O. cartilaginous cells by macroporous resin absorption and optimized the purification process in the experiment of orthogonal design with four factors (sample concentration and volume, and eluent concentration and volume) and three levels; the antibacterial and anti-cancer effects of the purified polysaccharides (OTP) were further examined. The results showed that polysaccharide purity reached 95 % in the optimized group, i. e., 1.6 mg/mL of sample (crude polysaccharides) concentration, 3.0 bed volume (BV) of sample volume, 65 % eluent (ethanol) concentration, and 3.0 BV of eluent volume. In the antibacterial experiment, the growth of three bacterial species, i. e., Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis was inhibited by OTP, whereas that of Escherichia coli was not affected; the largest diameter of the inhibitory zone was found on B. subtilis; the extracellular alkaline phosphatase activity and the electrical conductivity, nucleic acid, and protein levels of B. subtilis increased after OTP treatment, indicating that the inhibition of B. subtilis growth was caused by the leakage of cell contents. In the anti-cancer experiment, OTP decreased the cell viabilities of the tested human cancer cells, i. e., AGS (gastric cancer), HCT116 (colon cancer), HepG2 (liver cancer), and HeLa (cervical cancer), and the highest inhibitory effect was on HCT116. OTP promoted HCT116 apoptosis and affected the expression of apoptosis-related proteins, i. e., the expression of B-cell lymphoma-2 decreased and that of bcl-2 associated X protein, cytochrome c, caspase 9 and caspase 3 increased. The findings of the present study suggest that O. cartilaginous cell cultures have a potential application in food or drug production.
Keywords: Orostachys cartilaginous; anti-cancer activity; antibacterial activity; cell cultures; orthogonal design; polysaccharides.
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