Green teas (IC50 values in the range of 24.58–32.84 μg/mL) also
exhibited significantly (p b 0.05) higher antioxidant activity than
white teas (IC50 values in the range of 32.79–33.08 μg/mL) and
oolong teas (IC50 values in the range of 33.95–35.80 μg/mL) (Table 1).
Comparable DPPH results from investigations by Unachukwu et al.
(2010) on green teas havemean DPPH IC50 value of 23.26 μg/mL, slightly
lower than that obtained in our investigation; however, the preparation
methods of tea sample solutions slightly differed. Manian et al.
(2008) observed mean DPPH IC50 value for green tea extracts of
19.50 μg/mL with a different extraction method and solvent. These results
indicated that all the tea samples possessed a good free radical
scavenging capacity, and the antioxidant capacities of the three types
of tea mentioned abovewere significantly different (p b 0.05). Generally,
the processing methods for production of the three types of teawere
different. Green tea is an unfermented tea (degree of fermentation is 0),
which is particularly rich in polyphenol compounds. Nevertheless,
white tea and oolong tea are partially fermented teas, their degrees of
fermentation are about 20–30% and 30–60% respectively; the polyphenolic
compounds contained in them were partially oxidized during fermentation
(Harbowy & Balentine, 1997; Hsiao, Chen, & Cheng, 2010)