Table 2 Antibiotic-potentiating activity of Cytisus striatus extracts on different Staphylococcus aureus strains.

From: Looking to nature for a new concept in antimicrobial treatments: isoflavonoids from Cytisus striatus as antibiotic adjuvants against MRSA

Increased IZD (IZDc – IZDa) (mm)

S. aureus strains

Leaf

Flower

Twig

CIP

ERY

CIP

ERY

CIP

ERY

CECT 976

6.3 ± 1.0 (P)

9.1 ± 0.6 (P)

5.4 ± 1.2 (A)

4.5 ± 1.0 (A)

—

—

M116

7.0 ± 1.0 (P)

10.0 ± 0.0 (P)

—

—

—

—

RWW337

8.3 ± 0.6 (P)

—

—

—

—

—

RWW50

7.0 ± 0.0 (P)

5.0 ± 1.0 (A)

—

—

—

—

M82

4.0 ± 0.0 (A)

4.5 ± 0.0 (A)

—

—

—

—

RN6390

—

5.0 ± 0.3 (A)

—

—

—

—

SA1199B

14.0 ± 2.5 (P)

n.p.

17.3 ± 0.3 (P)

n.p.

—

n.p.

  1. The activity is expressed as the increase in the inhibition zone diameters (IZDs, mm) caused by ciprofloxacin (CIP) or erythromycin (ERY) when a plant extract is present in the Mueller-Hinton agar medium. The methanolic extracts of C. striatus leaves, flowers and twigs were applied at 0.5 mg/mL. Inhibition zones obtained with the combinations (IZDc) over antibiotic-single activity (IZDa) are given and the combinations are classified as: (—) indifferent (IZDc – IZDa < 4 mm); (A) additive (4 ≤ IZDc – IZDa < 6 mm); and (P) potentiation (IZDc – IZDa ≥ 6 mm)20, 35, 36. Data are means and SD from at least three independent experiments.
  2. n.p. not performed.
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