Chemical Composition, Antibacterial Activity, and Antibiotic Potentiation of Boswellia sacra Flueck. Oleoresin Extracts from the Dhofar Region of Oman

Figure 4

Isobologram for combinations of Najdi (extraction method 2) methanolic extract with chloramphenicol against (a) S. newport, (b) ciprofloxacin against S. aureus, (c) tetracycline against K. pneumonia, and (d) tetracycline against A. baylyi extract. The extracts and antibiotics were tested at various ratios against, and results represent mean FIC values of four replicates (n = 4). Ratio = % extract:% antibiotic. Ratios lying on or underneath the 0.5 : 0.5 line are considered synergistic (ΣFIC ≤ 0.5). Any points between the 0.5 : 0.5 and 1.0 : 1.0 lines are deemed additive (ΣFIC > 0.5–1.0).

(a)

(b)

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(d)