Table 3.

The DPPH scavenging ability (%) at 2 mg/mL and EC₅₀ (mg/mL) of 6a–k

Compound	Scavenging ability (%)	Compound	Scavenging ability (%)
6a	27.99 ± 0.49	6g	35.05 ± 0.32
6b	13.11 ± 0.12	6h	24.60 ± 0.31
6c	77.53 ± 0.47a	6i	28.32 ± 0.18
6d	33.47 ± 0.42	6j	38.39 ± 0.28
6e	37.49 ± 0.45	6k	68.28 ± 0.19c
6f e	64.50 ± 0.59b
Theophylline	12.14 ± 0.20	Vitamin C f	81.62 ± 0.21d

Data are mean ± SD (n = 3, p < 0.05)

EC₅₀ (mg/mL): ^a 1.1640 ± 0.0123, ^b 0.2212 ± 0.0011, ^c 1.4389 ± 0.0130, ^d 0.0083 ± 0.0002, ^e 0.3 mg/mL; ^f 0.04 mg/mL