Table 2.

Mutagenicity testing of Xanthium strumarium extract in the Salmonella/microsome assay (TA 100 and TA 98).

Concentration (μg/placa)	TA 100 Mean revertants/plate ± SD		TA 98 Mean revertants/plate ± SD
	−S9	+S9	−S9	+S9
0a	58.33 ± 16.56	62.60 ± 15.1	25.67 ± 3.79	38.33 ± 2.52
50	54.33 ± 5.13	64.10 ± 10.5	26.00 ± 4.36	38.67 ± 11.85
150	45.33 ± 4.73	60.04 ± 13.7	28.67 ± 7.64	45.67 ± 8.33
500	44.00 ± 2.00	60.33 ± 5.77	22.00 ± 5.29	35.67 ± 20.11
1500	46.67 ± 2.52	70.70 ± 7.37	26.00 ± 4.36	40.67 ± 8.62
5000	51.67 ± 3.21	67.31 ± 2.52	27.00 ± 2.65	38.33 ± 2.52
NaA1.5b	480.0 ± 22.6∗∗
2AF 20b		2280.0 ± 169.7∗∗		3300.0 ± 141.4∗∗
PA 100b			992.0 ± 11.3∗∗

+S9: with hepatic fraction S9; −S9: without hepatic fraction S9.

^aNegative control, dimethyl sulfoxide (DMSO).

^bPositive controls. NaA: sodium azide; 2AF: 2-aminofluorene; PA: pichrolonic acid.

**P < 0.01 (Student's t-test).