Spectrometric Investigation of the Antioxidant Activities of Dangcong Tea Aqueous Extracts against DPPH and ABTS Free Radicals
ZHENG Shan-yuan1, CHEN Tian-feng2, 3*, ZHENG Wen-jie2, WONG Yum-shing3*
1. School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510632, China 2. Department of Chemistry, Jinan University, Guangzhou 510632, China 3. State Key Laboratory of Agrobiotechnology, Department of Biology, the Chinese University of Hong Kong, Hong Kong, China
Abstract：The antioxidant activities of Dangcong tea aqueous extracts against DPPH and ABTS free radicals were evaluated using spectrometric methods. The results show that Dangcong tea aqueous extracts could effectively and rapidly inhibited the formation of ABTS and DPPH free radicals in a dose- and time-dependent manner, indicating the potent antioxidant activities of Dangcong tea aqueous extracts under both hydrophilic and hydrophobic conditions. In the optimized systems, the IC50 values of Baiye(Ⅰ, Ⅱ) and Fenghuang(Ⅲ, Ⅳ) Dangcong teas against ABTS free radical were 26.9, 25.5, 28.0 and 31.7 μg·mL-1, respectively, which were significantly lower than that of Trolox, the positive control (85.2 μg·mL-1), indicating the higher antioxidant activities of Dangcong teas. For DPPH free radical, the IC50 values for the Dangcong teas (Ⅰ-Ⅳ) were 49.8, 41.6, 47.3 and 64.5 μg·mL-1, respectively. Taken together, our results suggest the potential applications of Dangcong tea as functional food.
[1] Weisburger J H. Food Chem. Toxicol., 1999, 37: 943. [2] Yang C S, Maliakal P, Meng X F. Annu. Rev. Pharmacol. Toxicol., 2002, 42: 25. [3] Gardner E J, Ruxton C H, Leeds A R. Eur. J. Clin. Nutr., 2007, 61: 3. [4] Lin Y L, Juan I M, Chen Y C, et al. J. Agric. Food Chem., 1996, 44(6): 1387. [5] Shyu Y S, Lin J T, Chang Y T, et al. Food Chem., 2009, 115: 515. [6] Sharma O P, Bhat T K. Food Chem., 2009, 113: 1202. [7] Marghitas L A, Oltica G S, Daniel S D, et al. Food Chem., 2009, 115: 878. [8] Chen T F, Wong Y S. J. Agric. Food Chem., 2008, 56: 4352. [9] Miller N J, Sampson J, Candeias L P, et al. FEBS Lett., 1996, 384: 240. [10] De Beer D, Joubert E, Gelderblom W C, et al. J. Agric. Food Chem., 2003, 51(4): 902.
