Influence of Gallic Acid and Thai Culinary Essential Oils on Antibacterial Activity of Nisin against Streptococcus mutans

Table 4

FIC indexes of the combination of chlorhexidine, GA, and EOs against S. mutans ATCC 25175.

Compounds	MIC		Combined compounds	MIC		FIC index
	Alone	Combined		Alone	Combined
KLL (% v/v)	0.8	0.1	LG (% v/v)	0.1	0.025	0.37	SYN^∗
	0.8	0.1	GA (mg/mL)	4	0.5	0.25	SYN^∗
	0.8	0.2	Chlorhexidine (mg/mL)	0.0156	0.0019	0.37	SYN^∗
	0.8	0.05	LG (% v/v)+	0.1	0.025	0.56	IND^∗
			Chlorhexidine (mg/mL)	0.0159	0.0039
LG (% v/v)	0.1	0.1	GA (mg/mL)	4	4	2.00	IND^∗
	0.1	0.025	Chlorhexidine (mg/mL)	0.0156	0.0039	0.56	IND^∗
GA (mg/mL)	4	8	Chlorhexidine (mg/mL)	0.0156	0.0019	2.12	IND^∗

^∗IND: indifferent effect; SYN: synergistic effect.