earticle

영어

Anticancer and antioxidative activities of corn silks methanol extracts (CS-Me) containing glycoside flavonoids were examined. A corn variety was grown at the field of National Institute of Crop Science (NICS), Suwon, Korea. Before the silk-stage, ears of corn were covered with paper-bag to prevent pollination, and after 3-5 days unpollinated corn silks (female inflorescence) were collected and air-dried. The dried corn silks were extracted with MeOH and washed several times with water and then freeze-dried. The crude extract obtained was analyzed by reverse phase HPLC using C18 column and showed that it contains several phenolic compounds with glycoside flavonoids as major ones. This crude extract (CS- Me) was tested for anticancer and antioxidative activities. The anticancer activity of the corn silk extract toward PC-3 (human prostate cancer cell, ATCC No. CRL-1435™), A549 (carcinomic human lung alveolar basal epithelial cell, ATCC No. CCL-185™) and HepG2 (human hepatocellular carcinoma cell, ATCC No. HB-8065™), HT-29 (human colon cancer cell, HTB-38), and MKN45 (human gastric cancer cell, 80103) cell lines was examined by determining the inhibitory effect of cell growth. Cells were grown in RPMI 1640 medium supplemented with 10% (v/v) heat-inactivated FBS and 1% penicillin–streptomycin. The cells were maintained at 37oC under 5% CO2 and subcultured twice a week. For anticancer activity, cells were subcultured in 96-well plates at a density of 5 x 104 cells per well. After monolayer cultivation for 24 h, the medium was removed and replaced with 100 ul of the maintenance medium (MM) containing 2% FBS. Cells were then incubated for 24 h with different concentrations (0 – 200 ug/ml) of CS-Me dissolved in PBS or water. The cell viability was then determined by MTT assay at 570 nm. It was noticeable that the CS-Me showed the most significant inhibition of the cell growth against MKN45 cells while its effect was not significant toward other cell lines tested. The CS-Me inhibited MKN45 cell growth by about 40% and 60% at the concentrations of 50 and 100 ug/ml, respectively. Although it is quite preliminary, this result suggested that the crude methanol extract of corn silk may have a potent anticancer effect against human gastric cancer. Further characterizations of this extract may lead to identification of a potent therapeutic compounds for the prevention and/or decreasing the severity of gastric cancer. On the other hand, pretreatment of HepG2 cells with CS-Me dose dependently reduced the cytotoxicity of H2O2 and the intracellular ROS level. CS-Me also a significant DPPH radical scavenging activity and stimulated the expression of hemeoxygenase-1 (HO-1) mRNA in HepG2 cells. These results suggest that CS-Me has antioxidative activity.