Table 3.

In vitro inhibitory activities of the tested compounds 1–20 against DHFR enzyme.

Compound Number	IC50 (Mean ± SEM) (µM)
	DHFR
1	17.26 ± 0.43
2	14.33 ± 0.81
3	28.54 ± 0.22
4	31.57 ± 0.30
5	15.38 ± 0.12
6	13.45 ± 0.23
8	20.54 ± 0.14
9	8.46 ± 0.13
10	1.00 ± 0.85
11	17.13 ± 0.90
12	36.48 ± 0.72
13	0.09 ± 0.91
14	0.08 ± 0.37
15	0.04 ± 0.82
16	10.24 ± 0.97
17	27.42 ± 0.35
18	24.71 ± 1.26
19	29.00 ± 1.25
20	11.80 ± 0.79
Methotrexate	0.14 ± 1.38

IC₅₀: Compound concentration required to inhibit DHFR enzyme activity by 50%, SEM = standard error mean; each value is the mean of three values.