Triterpene and Steroids from Ludwigia abyssinica A. Rich (Onagraceae) Displayed Antimicrobial Activities and Synergistic Effects with Conventional Antibiotics

Table 2

Interactions of L. abyssinica components and antibiotics against bacteria and yeasts.

Microorganisms	EtOAc extract				Compound 1				Compound 3
	FICA	FICEx	FICI	Interpretation	FICA	FIC2	FICI	Interpretation	FICA	FIC5	FICI	Interpretation
E. coli	0.125	0.125	0.375	Synergistic	0.25	0.125	0.375	Synergistic	0.50	0.25	0.75	Additive
S. flexneri	0.125	0.062	0.187	Synergistic	0.25	0.125	0.375	Synergistic	0.50	0.125	0.625	Additive
S. aureus	0.062	0.031	0.093	Synergistic	0.125	0.031	0.156	Synergistic	0.25	0.125	0.375	Synergistic
C. tropicalis	0.25	0.125	0.375	Synergistic	0.25	0.125	0.375	Synergistic	0.25	0.25	0.50	Synergistic
C. albicans	0.125	0.125	0.25	Synergistic	0.125	0.062	0.187	Synergistic	0.25	0.125	0.375	Synergistic
C. neoformans	0.062	0.031	0.093	Synergistic	0.062	0.031	0.093	Synergistic	0.25	0.125	0.375	Synergistic

FICA: MIC of antibiotic tested in combination/MIC of antibiotic tested alone; FICEx: MIC of extract tested in combination/MIC of extract tested alone; FIC2: MIC of compound 1 tested in combination with antibiotic/MIC of compound 1 tested alone; FIC4: MIC of compound 3 tested in combination with antibiotic/MIC of compound 3 tested alone; FIC: MIC of antibiotic tested in combination/MIC of antibiotic tested alone + MIC of extract/compound tested in combination/MIC of extract/compound tested alone; antibiotics: ciprofloxacin for bacteria and fluconazole for yeasts.