Antibacterial and Antibiotic Modifying Potential of Crude Extracts, Fractions, and Compounds from Acacia polyacantha Willd. against MDR Gram-Negative Bacteria

Table 2

MICs and MBCs in µg/mL of fractions and compounds isolated from the leaf (APL) of Acacia polyacantha and chloramphenicol against a panel of selected Gram-negative bacteria.

Bacterial strains	Tested samples MIC and MBC (in bracket) values (µg/mL)
	Fractions from APL			Isolated compounds					Reference antibiotic
	APLa	APLb	APLd	4	5	6	7	8	chloramphenicol
Escherichia coli
ATCC8739	-	16 (-)	16 (-)	-	-	-	-	32 (-)	2 (64)
AG102	-	128 (-)	64 (-)	256 (-)	-	128 (-)	-	32 (-)	32 (256)
Enterobacter aerogenes
ATCC13048	-	256 (-)	8 (-)	128 (-)	64 (-)	-	-	32 (-)	16 (128)
EA27	-	-	128 (-)	256 (-)	256 (-)	-	-	-	32 (256)
Klebsiella pneumoniae
ATCC11229	16 (-)	64 (-)	16 (-)	64 (-)	32 (-)	-	-	32 (-)	32 (256)
KP55	-	16 (-)	64 (-)	128 (-)	256 (-)	-	128 (-)	32 (-)	64 (256)
Pseudomonas aeruginosa
PA01	-	128 (-)	64 (-)	-	-	-	-	-	64 (-)
PA124	-	256 (-)	64 (-)	256 (-)	128 (-)	-	-	32 (-)	256 (-)
Providencia stuartii
ATCC29916	-	128 (-)	-	-	-	-	-	64 (-)	64 (256)

(-): > 512 µg/ml for fractions or > 256 µg/ml for compounds; APL: leaf extract; APLa, APLb, and APLd are fractions from APL; 1: stigmasterol, 2:  β-amyrin, 3: 3-O-β-glucopyranosylstigmasterol, 4: 3-O-methyl-D-chiro-inositol, 5: epicatechin, 6: quercetin-3-O-glucoside, 7: 3-O-[β-xylopyranosyl-(1→4)-β-galactopyranosyl]-oleanolic acid, 8: 3-O-[β-galactopyranosyl-(1→4)-β-galactopyranosyl]-oleanolic acid; MIC values in bold: significant antibacterial effect [18]. Notes: MICs of fraction APLc > 512 µg/ml and MIC of compounds 1, 2, 3 were > 256 µg/ml in all tested bacteria.