Antioxidative Activities of Extracts of TNG 71 and TNG 57 Sweet Potato (Ipomoea batatas L.) Leaves

• Main Authors: Yu-Lin Jiang, 江育霖
• Other Authors: Shwu-Tzy Wu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/41164754964557725655

碩士 === 大葉大學 === 生物產業科技學系 === 102 === This study is aimed to evaluate the antioxidative activities of the extracts from the leaves of Ipomoea batatas L. TNG 71 and TNG 57. Various solvents (water, 40% alcohol, and 95% alcohol) were used to extract the fresh and dried leaves. Each extract was concentrated under a reduced pressure and freeze-drying process. The total contents of phenolics and flavoids as well as the antioxidative activities of each extract were analyzed. Assays of antioxidative activities included DPPH (α, α-diphenyl- β-picrylhydrazyl) radical scavenging ability, chelating ability of ferrous iron, reducing ability of ferric ion, and the scavenging ability of agreement of basic telecommunications services. Furthermore, Staphylococcus aureus and Escherichia coli were used to evaluate the antimicrobial activity of the extracts. The results showed that the highest (36%) the yields for both (TNG-71 and TNG-57) were from the 95% ethanol extracts. Total phenolic contents were highest (2.20 mg/g). The 40% ethanol extracts of fresh and dried leaves of TNG-71 and TNG-57 had the highest total phenolic contents. The total contents of flavoids were highest (5.53 mg/g) by 95%. Ethanol extracts for both fresh and dried leaves of TNG-71 and TNG-57 had the highest total contents of flavoids. For antioxidant capacity, 40% ethanol extracts of fresh TNG-71 and TNG-57 leaves had the highest scavenge ability of DPPH (IC50＝0.02 mg/mL). On the other hand, for dried TNG-71 and TNG-57 leaves, 95% ethanol extracts performed with better antioxidant activities (IC50＜0.01 mg/mL). The 95% ethanol extract of fresh TNG-71 leaves had the highest chelating abilities of ferrous iron (IC50＝0.28 mg/mL), and for the other aqueous extracts, the chelating abilities had also reached IC50＜0.26 mg/mL. For the reducing ability of ferric ion, the 95% ethanol extract was the highest under a concentration higher than 0.8 mg/mL. For the scavenging ability of ABTS, the 40% ethanol extract was the highest (IC50＜0.25 mg/mL) among all. In summary, the extracts (by 40% or 95% ethanol) of I. batatas leaves had potent antioxidative capacities. All extracts could inhibit the growth of S. aureus at a concentration of 0.05 mg/mL or higher, but no antimicrobial activity to E. coli. The results obtained in this study are useful for future research and development of functional foods.