An Evaluation of Protective Effect of Dioscorin from Various Chinese Yam Species on the Airway Epithelium Cells

• Main Authors: Tsue-Feng Lo, 羅翠芬
• Other Authors: Kuo-Wei Lin
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/29549488637904476689

碩士 === 靜宜大學 === 食品營養研究所 === 96 === Chinese yam (Dioscorea spp). is one of Chinese traditional produces for consumption and medicinal purposes. Dioscorin, storage protein purified from yams showed multi-functions such as antioxidant and anti-trypsin activity. The objectives of this study were to investigate the antioxidant activity and heat stability of dioscorin from various yam species (Tainung No. 2, TN2; Keelung, KL; Tashan, TS). The effect of dioscorin on human airway cells in vitro was evaluated via MTT test, immunophenotyping and cell cycle. Similar antioxidant activity was found for unheated and heated (100 °C, 1 min) dioscorin from all species indicating thermostability of dioscorin. The survival rate of A549 cells evaluated by MTT test showed a decreasing trend with ascending dioscorin levels of various yam cultivars, indicating toxicological effect of dioscorin on human pneumocyte A549 cells. The survival percentage of H460 cells decreased slightly as dioscorin concentrations increased. On the other hand, the survival percentage was relatively constant (120~145%) for normal white blood cells, suggesting no toxicological effect. Unheated dioscorin had higher inhibitory activity on cell growth than did heated dioscorin, but the cell survival percentage of A549 and H460 dropped slightly with increasing dioscorin levels. A possible inhibitory activity on the growth of A549 and H460 cells with no detrimental effect on normal white blood cells is proposed. Heating lowered dioscorin’s suppressive activity on cell growth, but this activity did not disappear regardless of heating. Results from the immunophenotyping of flow cytometer of A549 cells showed that addition of dioscorin didn’t induce inflamematory responses for the cell surface antigens. Additionally, cell cycle of A549 cells in response to dioscorin didn’t revral apparent apoptosis. In summary, dioscorin at present levels (100-1000 μg/ml) suppressed in vitro the growth of A549 and H460 cells without harming normal white blood cells. Potential utilization of dioscorin as a health agent is proposed; nonetheless, application of dioscorin into practical commercialized product as a protective media against lung cancer requires high scrutiny in vivo and human studies.