Antibacterial Activity of a Phenylpropanoid from the Root Extract of Carduus leptacanthus Fresen

Table 1

Zone of inhibition and minimum inhibitory concentrations of root extract and compound isolated from Carduus leptacanthus.

Bacterial strains	Diameter of zone of inhibition in mm, DZI (mean ± SEM)				MIC (mg/ml)
	Root extract (100 mg/ml)	Root extract (200 mg/ml)	Ciprofloxacin (5 µg)	1% DMSO	Root extract	Syringin
S. aureus	16.67 ± 0.33^a	18 ± 0.58^b	23.67 ± 0.33^c	8.00 ± 0.0^d	8.00 ± 0.0^d	13.33 ± 2.67^e
S. epidermidis	16.00 ± 0.58^a	24 ± 0.58^b	33.00 ± 0.0^c	8.00 ± 0.0^d	5.33 ± 1.33^d	16.00 ± 0.0^e
S. agalactiae	9.00 ± 0.0^a	10.67 ± 0.33^a	21.67 ± 0.33^b	8.00 ± 0.0^a	6.67 ± 1.33^d	16.00 ± 0.0^e
E. coli	8.00 ± 0.0^a	8.00 ± 0.0^a	32.67 ± 0.33^b	8.00 ± 0.0^a	32.00 ± 0.0	NA
P. aeruginosa	8.00 ± 0.0^a	8.00 ± 0.0^a	32.67 ± 0.33^b	8.00 ± 0.0^a	16.00 ± 0.0	NA
K. pneumonia	8.00 ± 0.0^a	8.00 ± 0.0^a	23.00 ± 0.0^b	8.00 ± 0.0^a	13.33 ± 2.67	NA

Note. Values are presented as the mean ± SEM; n = 3; means followed by a different letter indicate significant differences between different doses of the same treatments and negative control and positive control in the same row () for DZI and MIC separately; NA = not active up to the concentration of 16 mg/ml.