Abstract:

The antioxidant activity of persimmon tannin fractions with mean degree of polymerization of 2.61, 23.37
and 33.60 were evaluated both in vitro and in vivo by reducing power measurement, hydroxyl free radical, DPPH
free radical, ABTS+· and TBARs (thiobarbituric acid reactive substances) scavenging assays and lipid peroxidation
0.35 inhibition assay. The results showed that all the persimmon tannin fractions had high antioxidant potential in
all test systems. The IC50 values of fraction Ⅰ, Ⅱ, and Ⅲ were 19.60, 10.95 μg/mL and 7.74 μg/mL for DPPH free
radical, 11.33, 0.35 mg/mL and 0.24 mg/mL for hydroxyl radical, and 5.22, 1.91 μg/mL and 1.49 μg/mL for ABTS+·,
respectively. In addition, all the tannin fractions showed excellent lipid peroxidation inhibition. Furthermore, fraction Ⅲ
with the highest mean degree of polymerization prevented the bromobenzene-induced decrease in serum and liver
superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and decreased malondialdehyde levels in
the liver and serum of bromobenzene-treated mice. Its effects were no less strong than that of grape seed extract with
oligomer content above 70% in vivo. These results suggested that high-molecular-weight persimmon tannin may be a
very powerful antioxidant both in vitro and in vivo.

Key words: persimmon tannin, mean degree of polymerization, antioxidant activity, free radical, in vivo