Biological activity
We evaluated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scaven-
ging activity by 1. Compound 1 exhibited DPPH radical scavenging
activity with an IC50 value of 75 mM, which was almost the same
activity as that of a-tocopherol (IC50¼50 mM). The structure of 1
involves phenolic hydroxyl groups, which are considered to play a
significant role in expressing radical scavenging activity. Actually, the
derivatives 2 and 3 did not show any radical scavenging activity at the
concentration of 200 mM. Studies on detailed biological activities are
now underway.