Abstract: Brown pigment extracted from hickory shell with 95% alcohol and purified on AB-8 macroporous resin column was subjected to evaluation of antioxidant and antimicrobial activities and infrared spectroscopic analysis. The results showed that the total antioxidant capacity of the brown pigment at a concentration of 3.0 g/L was equivalent to 126.65 mmol/L α-tocopherol. The EC50 value (the effective concentration at which the absorbance was 0.5) of reducing power for the pigment was 0.286 g/L. The scavenging rate against hydroxyl free radicals reached 60.84 % at 1.0 g/L. The MIC (minimum inhibitory concentration) values of antibacterial effects on Saccharomyces cerevisiae, Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Aspergillus niger were 0.125, 0.25, 0.25, 1.0 g/L and 0.5 g/L, respectively. IR spectral analysis revealed the presence of benzene ring and phenolic hydroxyl in the pigment.

Key words: hickory shell, brown pigment, biological activities, minimum inhibitory concentration