Abstract:

Tannin in persimmon tree bark was ultrasonically extracted. The crude extract was purified by organic solvent
extraction and macroporous resin adsorption. The free radical scavenging activity of tannin samples with different purities
was studied using two different systems. The extraction yield of tannin in the crude extract was 5.6%. The optimum
conditions for purifying the crude extract with HPD-500 macroporous resin were as follows: a sample containing 1.2 mg/mL
tannin was loaded onto the column at a flow rate of 1.5 mL/min and eluted with 60% ethanol at a flow rate of 1.5 mL/min.
The purity of the crude extract was 5.6%, which was increased to 19.4% after macroporous resin purification. After ethyl
acetate extraction of the crude extract, the extract phase was purified to a purity of 11.5%. After further purification by
macroporous resin adsorption, the purity of the raffinate and extract phases was increased to 47.4% and 53.3%, respectively.
The crude extract and the resulting purified samples exhibited maximum percentage (69.07%, 92.96%, 80.19%, 94.02%
and 94.05%, respectively) of DPPH radical scavenging activity at 1 mg/mL with an IC50 value of 0.68, 0.13, 0.52, 0.12 and
0.11 mg/mL, respectively. The maximum percentage scavenging (43.04%, 83.00%, 73.99%, 94.68% and 96.23%,
respectively) of ·OH by the tannin samples with different purities at 0.9 mg/mL was obtained.

Key words: tannin, purification, antioxidant activity