Abstract: Eight compounds were isolated from the water extract of Pu-erh tea and their structures were elucidated by NMR and MS as gallic acid (1), (+)-catechin (2), (−)-epicatechin (3), (−)-epicatechin-3-O-gallate (4), (−)-epigallocatechin-3-O-gallate (5), (−)-epiafzelechin- 3-O-gallate (6), kaempferol (7), and quercetin (8). Their in vitro antioxidant activities were assessed by the DPPH and ABTS scavenging methods with microplate assays. The relative order of DPPH scavenging capacity for these compounds was compound 8 > compound 7 > compound 1 > compound 6 > compound 4 ≈ compound 5 > compound 2 > VC (reference) > compound 3, and that of ABTS scavenging capacity was compound 1 > compound 2 > compound 7 ≈ compound 8 > compound 6 > compound 5 > compound 4 > VC (reference) > compound 3. The results showed that these phenolic compounds contributed to the antioxidant activity of Pu-erh tea.
Keywords: Pu-erh tea; DPPH˙; ABTS˙+; chemical constituent; antioxidant activity
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Zhang, H.M.; Wang, C.F.; Shen, S.M.; Wang, G.L.; Liu, P.; Liu, Z.M.; Wang, Y.Y.; Du, S.S.; Liu, Z.L.; Deng, Z.W. Antioxidant Phenolic Compounds from Pu-erh Tea. Molecules 2012, 17, 14037-14045.
Zhang HM, Wang CF, Shen SM, Wang GL, Liu P, Liu ZM, Wang YY, Du SS, Liu ZL, Deng ZW. Antioxidant Phenolic Compounds from Pu-erh Tea. Molecules. 2012; 17(12):14037-14045.
Zhang, Hai M.; Wang, Cheng F.; Shen, Sheng M.; Wang, Gang L.; Liu, Peng; Liu, Zi M.; Wang, Yong Y.; Du, Shu S.; Liu, Zhi L.; Deng, Zhi W. 2012. "Antioxidant Phenolic Compounds from Pu-erh Tea." Molecules 17, no. 12: 14037-14045.