Evaluation of Antimicrobial Activity, Cytotoxicity, and Phytochemical Composition of Ocimum americanum L. (Lamiaceae)

Table 3

Inhibition of microbial growth by Ocimum americanum L. crude extracts and their fractions on twofold serial dilutions using the agar well diffusion method.

Microorganism	Conc mg/ml	Zone of inhibition (MM)						Positive control	Negative control
		Acetone extract	Chloroform fraction	Ethyl acetate fraction	Hydroethanol extract	Chloroform fraction	Ethyl acetate fraction
Bacillus cereus (gram +ve)	500	15.67^b ± 0.33	15.50^b ± 0.50	14.00^b ± 0.58	16.33^b ± 0.67	20.00^b ± 0.58	26.50^ab ± 0.29	30.00^a ± 1.16	0.00^d ± 0.00
	250	14.33^b ± 0.67	14.33^b ± 0.33	13.00^b ± 0.58	13.17^c ± 0.17	18.17^b ± 0.60	26.00^ab ± 0.00
	125	13.33^b ± 0.33	13.50^b ± 0.29	13.00^b ± 0.00	10.83^d ± 0.44	14.83^c ± 0.44	23.83^c ± 0.60
	62.5	13.83^b ± 0.17	12.00^c ± 0.58	11.50^c ± 0.29	11.00^d ± 0.00	9.83^c ± 4.94	20.00^d ± 0.58
	31.25	12.00^c ± 0.58	11.67^c ± 0.33	11.83^c ± 0.17	9.83^d ± 0.44	13.00^c ± 0.58	17.50^e ± 0.29
	15.62	11.50^c ± 0.29	11.33^c ± 0.33	10.67^c ± 0.17	9.67^d ± 0.33	9.33^c ± 0.33	14.33^f ± 0.44
	7.81	10.67^c ± 0.33	9.50^e ± 0.29	10.00^c ± 0.29	9.50^d ± 0.29	0.00^g ± 0.00	13.17^f ± 0.17
Escherichia coli	500	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	0.00 ± 0.00	0.00 ± 0.00	0.00 ± 0.00	45.00^a ± 0.58	0.00^d ± 0.00
Staphylococcus aureus (gram +ve)	500	14.50^b ± 0.29	12.00^b ± 0.58	11.17^b ± 0.44	17.17^b ± 0.44	18.50^b ± 0.29	16.83^b ± 0.60	50.00^a ± 1.15	0.00^d ± 0.00
	250	14.66^b ± 0.33	10.67^b ± 0.33	10.00^b ± 0.29	13.33^c ± 0.33	15.67^c ± 0.44	16.17^b ± 0.17
	125	14.00^b ± 0.58	9.67^c ± 0.33	9.17^b ± 0.17	10.50^d ± 0.29	12.83^d ± 0.44	11.83^b ± 0.17
	62.5	12.00^c ± 0.58	9.33^c ± 0.33	9.33^b ± 0.33	9.83^d ± 0.17	9.67^e ± 0.17	9.83^c ± 0.44
	31.25	11.66^c ± 0.88	9.67^c ± 0.33	0.00^d ± 0.00	6.17^d ± 3.09	9.17^e ± 0.17	6.17^c ± 3.09
	15.62	11.00^c ± 0.00	9.00^c ± 0.00	0.00^d ± 0.00	3.00^e ± 3.00	6.00^e ± 3.00	0.00^f ± 0.00
	7.81	9.67^c ± 0.33	0.00^d ± 0.00	0.00^d ± 0.00	3.00^e ± 3.00	0.00^f ± 0.00	0.00^f ± 0.00
Klebsiella pneumoniae	500	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	50.00^a ± 1.73	0.00^b ± 0.00
Candida albicans (fungus)	500	15.00^b ± 0.58	16.83^b ± 0.17	15.50^b ± 0.29	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	45.00^a ± 1.73	0.00^d ± 0.00
	250	14.33^b ± 0.33	14.67^c ± 0.33	9.00^b ± 4.51	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00
	125	12.33^c ± 0.33	12.00^d ± 0.58	12.50^b ± 0.29	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00
	62.5	11.17 ± 0.17	10.00^e ± 0.58	10.67^b ± 0.58	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00
	31.25	9.83^d ± 0.44	9.17^e ± 0.27	6.33^b ± 3.18	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00
	15.62	0.00^e ± 0.00	0.00^g ± 0.00	3.17^c ± 3.17	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00
	7.81	0.00^e ± 0.00	0.00^g ± 0.00	0.00^c ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00	0.00^b ± 0.00

Means flagged with the same superscript letter within the considered group, i.e., zone of inhibition, are not significantly different (). Positive control mean is flagged with “a”; negative control with “d”; and 500, 250, 125 mg/ml with “b” implying they are statistically the same/they had the same activity against S. aureus; and 62.5, 31.25, 15.62, and 7.81 mg/ml with “c,” because they also had statistically the same inhibitory activity against S. aureus; i.e., their differences are statistically significant ().