Study of the effect of the different parts of Morinda citrifolia L. (noni) on the green synthesis of silver nanoparticles and their antibacterial activity

The green synthesis of silver nanoparticles (AgNPs) using an aqueous extract of different parts of the Morinda citrifolia (noni, EM) plant, such as fresh leaves (EML), fruit pulp (EMF) and dried seeds (EMDS), is reported for the first time in this research work. The AgNPs synthesized with EM were characterized spectroscopically and microscopically, to determine its morphology, size, and polydispersity. The nanoparticles (NPs) were obtained with spherical morphology and did not present agglomeration. The AgNPs synthesized with EMDS (AgNPs/EMDS) had the smallest size (3 nm), while those synthesized with EML (AgNPs/EML) had the biggest size (11 nm). Also, it was performed a study of the variation of the metallic precursor concentration and the amount of fresh fruit (F) or dried seeds (DS), in the EM to determine its effect on the morphology, size, and polydispersity of the synthesized NPs. On the other hand, the bactericidal effectiveness of the synthesized NPs was evaluated against strains like E. coli and S. aureus. The greater bactericidal activity was obtained using AgNPs/EMDS against both strains; whereas a lower bactericidal efficiency was for AgNPs/EML, the aforementioned was due to the difference in the size of both AgNPs.

Automated summary

The green synthesis of silver nanoparticles using extracts from different parts of the Morinda citrifolia plant was characterized and evaluated for bactericidal effectiveness against E. coli and S. aureus. The nanoparticles were found to have different sizes and shapes depending on the part of the plant used, with those synthesized from dried seeds showing the smallest size and highest bactericidal activity against both bacterial strains.