Table 1. DPPH• antioxidant activity of compounds 1–13 and ascorbic acid as a positive control.

Compounds	IC50 (µM)a ± SD
1	43.3±0.62
2	45.46±1.89
3	49.08±4.36
4	45.12±4.77
5	5.89±0.71
6	29.51±2.4
7	8.68±0.15
8	34.21±2.12
9	23.03±1.06
10	17.09±0.21
11	NDb
12	18.59±0.67
13	16.0±0.86
Ascorbic acid	20.13±0.29

^aIC₅₀ (µM) is the scavenging capacity and phenol concentration expressed in µM that is able to quench 50% of DPPH radicals in a 100 µM solution. Each reported value is the mean of three separate measurements. ^b Not determined. Structures of compounds in Figure S1.