Comparison of the Antioxidant Activity of Pickled Tea (Camellia sinensis var. assamica) Extract with that of Other Teas

Abstract

Mieng (Camellia sinensis var. assamica), widely distributed in the northern part ofThailand, has been consumed as chewing tea. Mieng or pickled Assam tea leaves collectedfrom the markets in Chiang Mai were oven dried at 50??C and extracted by reflux extractionfor 120 min. The extracts were evaluated for antioxidant activities by DPPH radical andABTS cation radical assays. Their total phenolics contents were determined by Folin???Ciocalteu???s reagent-reactive compounds (FRC). Antioxidant activities and total phenoliccontents were compared with Chinese green tea, Oolong and black tea. Correlations ofABTS, DPPH and FRC tests were studied. Inhibition concentration at 50% of DPPH radicalscavenging activity and ABTS+??? radical cation decolorization were found in the range from12.63 to 36.59 ppm and from 3.48 to 21.61 ppm, respectively. Linear correlation betweenDPPH and ABTS radical scavenging activity (R2= 0.9980) was observed. Total phenoliccontents were ranged from 124.4 to 383.8 mg of gallic acid equivalent per gram extract. Thepickled Assam tea contained higher radical scavenging assay than those of black tea andlower than Chinese green tea and Oolong. The results showed that pickled tea had the high ofDPPH??? and ABTS+??? radical scavenging activity and comparable total phenolic contentamong other teas.