Exploration of Phyllanthus acidus mediated silver nanoparticles and its activity against infectious bacterial pathogen

Abstract

In our present investigation, synthesis of nontoxic, eco friendly and cost effective silver nanoparticles, Phyllanthus acidus (P. acidus) was used as starting material. The influence of phyto-constituents present in aqueous extracts of Phyllanthus acidus was found to be effective in reduction of silver nitrate to free silver nanoparticles (PA-AgNPs). HPTLC finger print analysis reveals the presence of flavonoid, quercetin in aqueous extracts of Phyllanthus acidus. Surface plasmon racemonance exhibited λ max at 462 nm through UV–Vis spectroscopy. Zeta size revealed that the size of nanoparticles were with in the range of 65–250 nm with polydisperse index (PDI) of 0.451. The negative charge of zeta potential value (− 16.4) indicates repulsion among PA-AgNPs with their excellent stability. FESEM-EDAX, XRD and TEM analysis confirmed the presence of nano-crystalline PA-AgNPs with different morphological textures. Further, PA-AgNPs has shown potent antibacterial effect on E. coli cells. The greater antibacterial effect (viable and dead cells) of PA-AgNPs were confirmed by using acridine orange (AO) dye which can able to provide insight of healthy as well as damaged DNA. Live cells emit florescence green and dead cells (treated with PA-AgNPS at 20 and 40 µg/ml) appear as pale orange red colour. Post treatment, investigations of PA-AgNPs on E. coli cells under SEM was found to be effective against cell membrane damages which leads to cell death or cell growth arrest. Hence, from the above findings, we strongly recommend silver nanoparticles from Phyllanthus acidus can be used as a potential source for antimicrobial agent for chronic infections and also against other harmful microorganisms.

Populus ciliata mediated synthesis of silver nanoparticles and their antibacterial activity

“…Figure 4b shows that particles were of spherical shape with nonuniform size (Matei, Matei, Matei, Cogălniceanu, & Cornea, 2020) distribution which is also indicated by particle distribution histogram, as shown in Figure 4c. The spherical shape of the AgNPs was in agreement with the already synthesized AgNPs via green route (Rather et al, 2020; Sowmya et al, 2018). The average particle size was being estimated using smaller particles which constitute major proportion and it came out to be 4 nm.…”

“…These crystal planes are features of the face centered cubic system of AgNPs. Such a crystal system has already been reported by different researchers working on the green synthesis of AgNPs (Anjum & Ashraf, 2020; Sowmya et al, 2018). Similar crystal system has also been observed by some other researchers using aqueous leaf extract of Cucumis prophetarum .…”

“…Thus, the most probable reason behind agglomeration is the adhesion of small particles. The small sized particles have greater penetration power into the cells and may cause an effective cellular destruction (Sowmya et al, 2018). Recent studies also indicated the accumulation of nano sized AgNPs on the celluar cell wall, subsequent formation of pits on cell wall and consequent cell death (He et al, 2017).…”

“…Although, the use of silver as bactericidal agent has been in practice since many centuries but as compared to metallic silver, its nanoparticles have been found most effective against different pathogenic bacteria (Rajput, 2015; Rather, Shincy, & Sundarapandian, 2020). Keeping in mind their biomedical applications, several research groups have synthesized AgNPs with variety of morphologies and sizes using, physical, chemical as well as biological methods (Ajayi & Afolayan, 2017; Ovais et al, 2018; Sowmya, Lavakumar, Venkateshan, Ravichandiran, & Saigopal, 2018). The fabrication of AgNPs using physical and chemical methods is less desirable because of the associated disadvantages such as long reaction times, use of toxic solvents, and multistep synthesis (Gamboa, Rojas, & Martínez, 2019).…”

“…Hence, many plant materials have been used for fabrication of AgNPs and these NPs were found effective in anti‐bacterial studies against both gram positive and gram negative bacteria (Abdelghany et al, 2018; He et al, 2017). The bacteria killing ability of AgNPs could be attributed to the binding ability of these NPs with sulphur and phosphorous atoms of the bacterial cell wall, subsequent penetration, resulting into the bacterial cell death (Anbu, Gopinath, Yun, & Lee, 2019; Sowmya et al, 2018). The higher activity of the AgNPs has been linked with the smaller size of the particles as these particles are capable to release the silver ions very easily (Behravan et al, 2019).…”