Free radical scavenging and apoptotic effects of Cordyceps sinensis fractionated by supercritical carbon dioxide

• Published in: Food and chemical toxicology 2005-04, Vol.43 (4), p.543-552
• Main Authors: Wang, Be-Jen, Won, Shen-Jeu, Yu, Zer-Ran, Su, Chun-Li
• Format: Article
• Language: English
• Subjects: anticarcinogenic activity; Apoptosis; Apoptosis - drug effects; Biological and medical sciences; butterflies; carbon dioxide; Carbon Dioxide - chemistry; Carcinoma, Hepatocellular - pathology; Cell cycle; cell proliferation; Chromatography, Supercritical Fluid; Colon cancer; Colonic Neoplasms - pathology; colorectal neoplasms; cordycepin; Cordyceps; Cordyceps - chemistry; Cordyceps sinensis; DNA - metabolism; DNA fragmentation; dose response; fractionation; Free radical; Free Radical Scavengers - pharmacology; free radicals; fungi; Hepatoma; herbal medicines; Humans; Lepidoptera; Liver Neoplasms - pathology; Medical sciences; moths; Oriental traditional medicine; parasites; parasitic fungus extracts; plant extracts; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; polysaccharides; Solvents; Stem Cells; supercritical fluid extraction; Supercritical fluid extractive fractionation; Toxicology; Tumor Cells, Cultured
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2004.12.008

Supercritical carbon dioxide (SC-CO 2) was used as the elution solvent for fractioning ethanolic extract (E) of Cordyceps sinensis (CS), a traditional Chinese herbal remedy, into R, F1, F2, and F3 fractions. This extractive fractionation method is amenable to large scale and is nontoxic. These four fractions were characterized in terms of total polysaccharides and cordycepin concentrations, scavenging ability of free radicals, and anti-tumor activities. Experimental results demonstrated that fractionation altered the distributions of total polysaccharides and cordycepin in fractions. Fraction R was the most active fraction to scavenge free radicals and inhibit the proliferation of carcinoma cells, followed by the fraction F1 and the extract E. The effect of scavenging on 1,1-diphenyl-2-picryl hydrazyl (DPPH) of CS extract and fractions at 2 mg/ml was R (93%), F1 (75%), E (66%), F2 (47%), and F3 (27%). The IC 50 (50% cell growth inhibitory concentration) of tumor cell proliferation and colony formation on human colorectal (HT-29 and HCT 116) and hepatocellular (Hep 3B and Hep G2) carcinoma cells by fraction R were around 2 μg/ml. Conversely, R did not affect the growth of normal dividing human peripheral blood mononuclear cells (PBMC) by exhibiting a large value of IC 50 over 200 μg/ml. Accumulation of tumor cells at sub-G 1 phase and the fragmentation of DNA, typical features of programmed cell death, were observed in a time and dose dependent manner. Scavenging of free radicals and anti-cancer activity (value of IC 50) correlated closely with the quantities of polysaccharides (Spearman’s rho = 0.901 and −0.870, respectively). Taken together, our findings suggest that fraction R, obtained by SC-CO 2 fluid extractive fractionation, showed strong scavenging ability and selectively inhibited the growth of colorectal and hepatocellular cancer cells by the process of apoptosis.