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

Table 3

MIC values (μg/mL) for the B. sacra oleoresin extracts against selected bacterial pathogens.

				Gastrointestinal pathogens					Autoimmune inflammatory trigger bacteria
				E. coli	E. faecalis	S. aureus	S. newport	S. sonnei	P. mirabilis	K. pneumoniae	A. baylyi	P. aeruginosa
Najdi	Method 1	M	DD	2483	850	1128	626	1540	675	783	1086	2186
			LD	1165	476	628	146	1348	605	625	805	2250
		W	DD	—	—	2550	3263	—	1284	2568	—	—
			LD	2750	1860	1876	1245	—	1550	2250	1875	—
	Method 2	M	DD	1170	476	521	147	1256	477	228	736	1899
			LD	826	225	326	86	920	280	126	437	1558
		W	DD	—	—	2860	1280	—	583	576	1873	—
			LD	1890	1387	1256	863	2540	625	528	920	—
	Method 3	M	DD	896	625	625	526	1386	487	428	588	1860
			LD	526	376	326	128	664	225	258	376	1280
		W	DD	—	2568	2803	2560	—	970	826	1080	—
			LD	1566	—	1440	1280	—	486	120	500	—
Sahli	Method 1	M	DD	2287	927	1883	825	2250	1827	1250	>5000	—
			LD	1680	475	826	368	1858	1250	1125	2500	2285
		W	DD	—	—	—	—	—	—	—	—	—
			LD	—	1854	2256	1440	—	—	—	—	—
	Method e 2	M	DD	1568	876	1059	437	1405	835	825	2583	—
			LD	1125	283	528	128	876	750	576	1265	2650
		W	DD	—	—	—	2500	—	—	2836	—	—
			LD	—	—	—	1868	—	—	1560	>5000	—
	Method 3	M	DD	920	827	1298	788	2568	625	528	1287	—
			LD	765	358	625	246	1280	574	325	870	1560
		W	DD	—	—	—	3285	—	—	2256	2862	—
			LD	—	—	—	2500	—	>5000	1280	1255	—
Houjari	Method 1	M	DD	1830	450	1276	1540	1863	927	1045	1653	—
			LD	854	128	665	1194	1280	825	805	1295	1875
		W	DD	1280	856	—	—	—	1580	1293	—	—
			LD	874	680	1128	2580	3860	1135	960	>5000	—
	Method 2	M	DD	1147	540	920	883	1086	625	459	685	2279
			LD	486	68	376	750	826	480	275	775	876
		W	DD	2280	1580	—	—	—	—	2876	1287	—
			LD	1488	726	>5000	1478	1886	2586	2280	1476	—
	Method 3	M	DD	827	525	1352	1855	1455	1250	400	1180	—
			LD	628	156	728	1480	926	750	325	838	1358
		W	DD	—	1156	—	—	—	—	2500	—	—
			LD	—	800	>5000	>5000	>5000	—	1186	1586	—
LD antibiotic controls MIC values		Penicillin	2.5	0.63	—	1.25	1.25	1.25	1.25	2.5	—
		Erythromycin		1.25	0.63	2.5	1.25	2.5	1.25	2.5	0.63	—
		Chloramphenicol	1.25	1.25	1.25	1.25	0.64	0.63	1.25	0.16	2.5
		Ciprofloxacin	0.32	0.08	0.64	0.64	0.64	0.08	0.08	0.08	0.32
		Tetracycline	1.25	1.25	1.25	2.5	1.25	1.25	0.32	0.32	—

M = methanolic extract; W = aqueous extract; DD = disc diffusion MIC value; LD = liquid dilution MIC value; Methods 1, 2, and 3 refer to the extraction method used; — indicates that no inhibitory activity was detected at any concentration tested. Extracts with noteworthy activity (MIC < 1000 μg/mL) or antibiotics (MIC <1 μg/mL) are indicated in bold. Bacteria are considered susceptible to conventional antibiotics if MIC ≤ 1 μg/mL.