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.A 96-well multiplate was used for the DPPH radical scavenging assay.6
Compound 1 and a-tocopherol as a positive control were dissolved in MeOH
to prepare samples of 1 mM, before being diluted with MeOH to prepare
samples of a linear concentration system of 0.01–0.5 mM. A volume of 90 ml of
200 mM DPPH dissolved in MeOH and 10 ml of sample were mixed in the
microplate. After 1 h incubation at room temperature, the absorbance was
measured at 540 nm.