Exploitation of endophytic fungus, Guignardia mangiferae for extracellular synthesis of silver nanoparticles and their in vitro biological activities

Abstract

The aim of this study was to synthesize highly biocompatible and functionalized silver nanoparticles using endophytic fungi isolated from the leaves of medicinal plants. Among 13 fungi tested, the isolate, Guignardia mangiferae (Bios PTK 4) extracellularly synthesized well-dispersed and extremely stable silver nanoparticles under optimized reaction conditions within 12 h. These nanoparticles were characterized by HR-TEM, SAED, XRD and EDX analyses. G. mangiferae synthesized 5-30 nm sized, spherical shaped silver nanoparticles. Effect of pH on the antibacterial activity of silver nanoparticles was studied using well diffusion assay; on the basis of particle stability and antibacterial activity, pH 7 was found to be optimum. The leakage of intracellular components has clearly demonstrated that silver nanoparticles damage the bacterial cells by formation of pores, which affect the membrane permeability and finally leads to cell death. In addition, silver nanoparticles exhibited excellent antifungal activity against plant pathogenic fungi. Cytotoxic effects of silver nanoparticles showed IC50 values of 63.37, 27.54 and 23.84 μg/mL against normal African monkey kidney (Vero), HeLa (cervical) and MCF-7 (breast) cells, respectively, at 24 h incubation period. Thus, the obtained results convincingly suggest that silver nanoparticles synthesized from G. mangiferae are highly biocompatible and have wider applicability and they could be explored as promising candidates for a variety of biomedical/pharmaceutical and agricultural applications.

Mycosynthesis of silver and gold nanoparticles: Optimization, characterization and antimicrobial activity against human pathogens

“…6 and Table 2 test concentration of 1 mg/ mL. The zone of inhibition exhibited by silver nanoparticles was found to be higher than our previous study (Balakumaran et al, 2015) and slightly lower than those reported by Elbeshehy et al (2015). The highest antimicrobial activity was recorded against Gram-negative bacteria and this result was in good agreement with the earlier studies (Balakumaran et al, 2015;Elbeshehy et al, 2015).…”

“…Similarly, no change in the peak at 535 nm was also noticed for gold nanoparticles. However, the peaks for silver and gold nanoparticles got shifted during the course of third month but in both cases, there was no sign of aggregation of nanoparticles observed (Balakumaran, 2015). On the contrary, Bacillus spp.…”

“…On the other hand, gold nanoparticles did not show any zone of inhibition (Balakumaran, 2015). Consequently, silver nanoparticles alone were used for further studies.…”

Applying Taguchi design and large-scale strategy for mycosynthesis of nano-silver from endophytic Trichoderma harzianum SYA.F4 and its application against phytopathogens

“…There are many previous studies connected the stability and antibacterial activity of Ag NPs bio-fabricated from different endophytic fungi with pH and reported the optimum pH was 76390, pH 5428091 and pH 3 reported by9293949596. Finally6297 recorded that biosynthesis of Ag NPs by using extracellular fraction of Trichoderma reesei and T. harzianum without adjusting pH and reported the formation of polydisperse spherical and occasionally ellipsoid Ag NPs in the size range from 5–63 nm at room temperature started within 3 hr.…”

Nanosilver: new ageless and versatile biomedical therapeutic scaffold

“…(9.37 mm). 259 In another study, AgNO 3 was tested against three fungi namely Trichoderma spp. (ATCC 18648), Mucor spp.…”