title: Antioxidative activity of water extract of sweet potato leaves in Taiwan.
abstract: This study reports the preparation of four varieties of water extract from sweet potato leaves from Taiwan, including TNG10, TNG57, TNG66 and YSP, and evaluates their antioxidative activity. The EC50 values (scavenging DPPH radicals) of TNG10, TNG57, TNG66 and YSP were 0.27±0.01, 0.19±0.01, 0.41±0.02, and 0.31±0.02mg/ml, respectively, on a freeze-dry weight basis. The total phenolic contents of these water extracts were in the order: TNG57>TNG10>TNG66>YSP. The TNG10 and TNG57 extracts exhibited better reducing power and scavenging effects of superoxide radicals than did TNG66 and YSP. At a concentration of 1mg/ml, TNG10 and TNG57 significantly protected HaCaT cells from H2O2-induced cytotoxicity. The water extracts of YSP had more flavonoids than had those of TNG66 which may have contributed to their higher activity in many antioxidative assays. These results suggest that the water extracts of all four varieties of sweet potato leaves, and especially TNG10 and TNG57, display potent antioxidative effects.
authors.affiliation: Department of Nursing, Chang Gung Institute of Technology, No. 2, Chia-pu Road, West Sec. Pu-tz, Chia-Yi 613, Taiwan.
authors.forename: Wayne C
authors.initials: WC
authors.lastname: Liao
authors.affiliation: Department of Agronomy, Chiayi Agricultural Experimental Station, Agriculture Research Institute, No. 2, Min-Chen Road, Chia-Yi 600, Taiwan.
authors.forename: Yung-Chang
authors.initials: YC
authors.lastname: Lai
authors.affiliation: Department of Applied Cosmetology, Hungkuang University, No. 34, Chung-Chie Road, Shalu, Taichung 433, Taiwan.
authors.forename: Ming-Chen
authors.initials: MC
authors.lastname: Yuan
authors.affiliation: Department of Applied Cosmetology, Hungkuang University, No. 34, Chung-Chie Road, Shalu, Taichung 433, Taiwan.
authors.forename: Ya-Lin
authors.initials: YL
authors.lastname: Hsu
authors.affiliation: Department of Applied Cosmetology, Hungkuang University, No. 34, Chung-Chie Road, Shalu, Taichung 433, Taiwan. Electronic address: cfchan@sunrise.hk.edu.tw.
authors.forename: Chin-Feng
authors.initials: CF
authors.lastname: Chan
keywords: Antioxidative activity; Reducing power; Superoxide radicals; Sweet potato