Biogenic synthesis of silver nanoparticles using a pod extract of Cola nitida: Antibacterial and antioxidant activities and application as a paint additive

Peer review under responsibility of Taibah University.

Figures & data

Fig. 1 Biogenic synthesis of AgNPs using pod extract of C. nitida.

Fig. 2 UV–Vis absorption spectrum of AgNPs synthesized using pod extract of C. nitida.

Fig. 3 FTIR spectrum of AgNPs synthesized using pod extract of C. nitida.

Fig. 4 Transmission electron micrograph (A), selected area electron diffraction pattern (B) and energy dispersive X-ray signal (C) of the biosynthesized AgNPs using pod extract of C. nitida.

Fig. 5 The antibacterial activities of synthesized AgNPs using pod extract of C. nitida against some clinical bacterial isolates (A, E. coli Wound; B, P. aeruginosa Ear; C, P. aeruginosa Wound; and D, K. granulomatis Ear).

Table 1 Resistance pattern of the test isolates.

No of antibiotics	Resistance pattern^a	Isolate	Source
2	Crx, Caz	KE	Ear
8	Crx, Caz, Gen, Cxm, Ofl, Aug, Nit, Cpr	PW	Wound
	Crx, Caz, Gen, Cxm, Ofl, Aug, Nit, Cpr	PE	Ear
	Crx, Caz, Gen, Cxm, Ofl, Aug, Nit, Cpr	EW	Wound

a Antibiotics abbreviations are as defined under Section 2.5; KE, K. granulomatis; PW, P. aeruginosa; EW, E. coli.

Table 2 Zone of inhibition (mm) of AgNPs on some bacterial isolates.

Isolate	Source	Concentration of AgNPs (μg/ml)
		150	120	100	80	50
EW	Wound	19 ± 0.9	16 ± 0.5	15 ± 0.3	13 ± 0.4	12 ± 0.6
PE	Ear	28 ± 1.1	30 ± 0.8	24 ± 0.4	18 ± 0.4	15 ± 0.6
PW	Wound	13 ± 0.6	12 ± 0.4	11 ± 0.3	9 ± 0.5	8 ± 0.5
KE	Ear	11 ± 0.8	11 ± 1.0	10 ± 0.2	7 ± 0.0	7 ± 0.0

KE, K. granulomatis; PW, P. aeruginosa; EW, E. coli; each value is an average of three readings.

Fig. 6 The antibacterial activities of synthesized AgNPs using pod extract of C. nitida as additive in emulsion paint.

Fig. 7 The antifungal activities of synthesized AgNPs using pod extract of C. nitida as additive in emulsion paint.

Table 3 The DPPH-radical scavenging activity of the biosynthesized AgNPs.

	% DPPH scavenging activity					IC50 (μg/ml)
Test material (μg/ml)^a	20	40	60	80	100
AgNPs	32.81	65.62	70.43	93.90	100	43.98
Standards (μg/ml)^a	200	400	600	800	1000
Quercetin	43.87	52.71	61.54	63.23	74.62	430
β-Carotene	11.11	27.78	50.01	55.56	66.67	710

a Concentration.

Table 4 The ferric ion reducing activity of the biosynthesized AgNPs.

	Ferric ion reduction (%)
Test material (μg/ml)^a	20	40	60	80	100
AgNPs	13.62	20.44	22.72	40.88	49.96
Standards (μg/ml)^a	200	400	600	800	1000
Quercetin	12.05	20.39	28.73	63.95	100
β-Carotene	11.53	26.92	19.23	42.31	65.38

a Concentration.