FOOD SCIENCE ›› 2013, Vol. 34 ›› Issue (7): 111-114.doi: 10.7506/spkx1002-6630-201307023

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Antioxidant Activity of Isoquercitrin and Caffeoylquinic Acid Derivatives from Sweet Potato Stems and Leaves

LI Jia-yin1,2,YU Huan2,SHI Bo-yang1,2,LI Mi-lu2,LU Ying1,2,*   

  1. 1. National Research Center of Engineering Technology for Utilization of Functional Ingredients from Botanicals, Hunan Agricultural University, Changsha 410128, China;2. College of Horticulture and Gardening, Hunan Agricultural University, Changsha 410128, China
  • Received:2012-01-07 Revised:2013-02-05 Online:2013-04-15 Published:2013-03-20
  • Contact: LU Ying E-mail:canghaizhilang@126.com

Abstract: The antioxidant activity of four major polyphenolic compounds, namely quercetin-3-O-β-D-glucoside (Q-Glu), 4,5-di-O-caffeoylquinic acid (4,5-diCQA), 3,4-di-O-caffeoylquinic acid (3,4-diCQA) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA) derived from sweet potato stems and leaves were evaluated based on reducing power, DPPH, hydroxyl and superoxide anion free radical scavenging, and anti-lipidperoxidation assays and compared with that of VC. These four polyphenolic compounds demonstrated strong antioxidant activity in a concentration-dependent manner. The IC50 values of Q-Glu, 3,5-diCQA, 3,4-diCQA, 4,5-diCQA against DPPH and hydroxyl free radicals were 47.27, 41.61, 43.55, 46.02 μmol/L, and 190.99, 151.20, 151.24, 217.31 μmol/L, respectively, whereas the IC50 values of Q-Glu3, 5-diCQA, and 3, 4-diCQA against superoxide anion free radical were 0.81, 0.46, 0.71 mmol/L, respectively. In anti-lipidperoxidation assay the IC50 values of 3,5-diCQA, 3,4-diCQA, and 4,5-diCQA were 4.44, 2.53, 3.13 mmol/L, respectively. Within the studied concentration range, however, 4,5-diCQA and Q-Glu did not reach 50% superoxide anion free radical scavenging and lipidperoxidation. Among these compounds, 3,5-diCQA showed the strongest reducing power and radical scavenging activity, and the antilipidperoxidation activity of 3,4-diCQA was the highest. These results show that these four polyphenolic compounds from sweet potatoes stems and leaves have significant antioxidant effects and are promising natural antioxidants.

Key words: sweet potato, polyphenols, antioxidants, reactive oxygen species

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