Bactericidal activity of biosynthesized silver nanoparticles against human pathogenic bacteria

Figures & data

Figure 1. UV–visible spectrum for the reaction of plant extracts with AgNO₃ solution.

Figure 2. SEM images showing well-dispersed silver nanoparticles formed by extracts of plants: A. vera (A), P. oleracea (B) and C. dactylon (C).

Table 1. Antibacterial activities of Ag-NPs biosynthesized by extracts from A. vera (A), P. oleracea (B) and C. dactylon (C).

	Zone of inhibition (mm diameter)
	50 µg/mL			5 µg/mL			0.5 µg/mL
Bacterial strain	A	B	C	A	B	C	A	B	C	Streptomycin	Negative control
B. subtilis	16.5	15.0	15.6	14.8	12.8	14.2	10.8	8.8	10.0	28.7	0.0
B. cereus	11.4	9.4	12.7	8.1	7.1	8.7	5.4	4.8	5.7	25.9	0.0
S. aureus	18.1	17.7	16.5	16.3	14.8	13.3	13.4	12.8	13.0	31.0	0.0
E. faecalis	6.2	5.2	5.9	4.2	3.2	4.2	2.5	2.9	2.8	27.7	0.0
S. typhi	6.3	5.5	6.0	4.2	4.0	5.1	3.4	3.2	3.2	24.8	0.0
Shigella sp.	5.4	5.8	7.0	4.6	4.0	5.0	2.8	2.2	3.8	21.3	0.0
E. coli	6.0	4.9	5.0	3.8	3.2	4.5	3.4	2.8	3.0	40.7	0.0
P. aeruginosa	6.4	5.0	6.0	6.0	4.8	5.6	3.3	3.0	3.0	16.9	0.0
A. baumannii	5.8	4.8	5.0	4.7	4.2	4.7	3.8	3.0	2.8	18.9	0.0

Table 2. MIC values of different types of Ag-NPs biosynthesized by extracts from A. vera (A), P. oleracea (B) and C. dactylon (C).

	MIC (mg(Ag)/L)
Bacterial strain	A (10–30 nm)	B (15–40 nm)	C (25–60 nm)
B. subtilis	2.6	3.2	4.8
B. cereus	2.4	3.25	4.5
S. aureus	1.5	2.8	5
E. faecalis	2	3	4
S. typhi	3	4	6
Shigella sp.	2.9	4.2	6.5
E. coli	3.4	4.35	5.5
P. aeruginosa	3	3.8	5.7
A. baumannii	3.7	5	5.4

Figure 3. SEM analysis of non-treated control bacterial cells (A) and S. aureus treated with Ag-NPs formed by extracts from A. vera (B), P. oleracea (C) and C. dactylon (D).