Table 1.

The antibacterial activity of coumarins against R. solanacearum.

Number	Compound	Antibacterial Rate (%) (Mean ± SD) a
		10 mg/L	100 mg/L
1	Coumarin	3.9 ± 1.1 *	50.3 ± 3.3 *
2	Scopoletin	1.5 ± 7.6	32.6 ± 4.9 *
3	Scoparone	1.0 ± 7.0	17.3 ± 2.9 *
4	Isofraxidin	2.5 ± 3.2 *	0.7 ± 1.4 *
5	3-Acetyl-2H-chromen-2-one	6.3 ± 4.7	10.7 ± 2.7 *
6	4-Methoxycoumarin	7.3 ± 1.9 *	54.1 ± 4.2 *
7	Osthole	0.2 ± 1.9 *	3.1 ± 3.3 *
8	4-Hydroxycoumarin	2.1 ± 5.7 *	4.9 ± 6.6 *
9	Umbelliferone	7.3 ± 3.0	59.7 ± 3.8
10	Esculetin	9.2 ± 2.8	71.4 ± 2.1 *
11	Daphnetin	13.3 ± 3.0	97.4 ± 0.7 *
12	Psoralen	13.1 ± 0.8	57.1 ± 8.8
13	Xanthotol	8.5 ± 5.4	80.1 ± 2.5 *
14	Xanthotoxin	6.3 ± 5.0	36.3 ± 5.4 *
15	Imperatorin	6.5 ± 2.9 *	19.1 ± 2.8 *
16	Isoimperatorin	4.1 ± 2.0 *	23.9 ± 6.3 *
17	Bergapten	4.7 ± 2.4 *	21.9 ± 1.6 *
18	Isopimpinellin	0.3 ± 1.6 *	22.5 ± 5.1 *
Positive Control	Thiodiazole Copper	12.2 ± 1.7	63.6 ± 2.9

^a: The experiment was repeated in triplicates. Asterisks indicate statistically significant differences in antibacterial activity against R. solanacearum compared with thiodiazole copper treatment. (* indicates p < 0.05, Student’s t test).