An Efflux Pumps Inhibitor Significantly Improved the Antibacterial Activity of Botanicals from Plectranthus glandulosus towards MDR Phenotypes

Table 2

Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in μg/mL of isolated compounds of P. glandulosus against selected Gram-negative bacteria.

Bacteria	Compounds, MICs (MBCs) in μg/mL
	6	11	12	15 + 16	17
Escherichia coli
ATCC 8739	-	-	-	-	-
AG 102	128 (-)	-	-	64 (-)	-
Enterobacter aerogenes
ATCC 13048	-	-	-	-	-
EA 27	-	-	-	-	-
Klebsiella pneumoniae
ATCC 11296	256 (-)	64 (-)	-	64 (-)	64 (-)
KP 55	-	-	-	-	-
Providencia stuartii
ATCC 29916	-	-	-	256 (-)	512 (-)
PS 2636	64 (-)	256 (-)	64 (-)	512 (-)	-
Pseudomonas aeruginosa
PA 01	-	-	-	-	-
PA 124	-	-	-	-	-

(-): ≥512 μg/mL; MIC, minimum inhibitory concentration; MBC, minimum bactericidal concentration; 6, chrysoeriol; 11, 5,6-dihydroxy-7,3′,4′-trimethoxyflavone; 12, ladanein; 15, chrysoeriol 5-O-β-D-glucopyranoside; 16, 7-O-methyl luteolin 5-O-β-D-glucopyranoside; 17, luteolin 5-O-β-D-glucopyranoside.