Swift fabrication of Ag nanostructures using a colloidal solution of Holostemma ada-kodien (Apocynaceae) – Antibiofilm potential, insecticidal activity against mosquitoes and non-target impact on water bugs

Publication date: Available online 17 February 2018
Source:Journal of Photochemistry and Photobiology B: Biology
Author(s): Sami A. Alyahya, Marimuthu Govindarajan, Naiyf S. Alharbi, Shine Kadaikunnan, Jamal M. Khaled, Ramzi A. Mothana, Mohammed N. Al-anbr, Baskaralingam Vaseeharan, Ramachandran Ishwarya, Mariappan Yazhiniprabha, Giovanni Benelli
Recent research in parasitology focused on the efficacy of green fabricated nanomaterials as novel insecticides. In this study, we synthesized poly-dispersed, stable, and cluster-shaped silver nanoparticles (AgNPs) using the leaf extract of Holostemma ada-kodien. The cluster-shaped AgNPs were characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray, and X-ray diffraction analysis. The efficacy of H. ada-kodien leaf extract and AgNPs in vector control was evaluated against the mosquitoes Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, which act as major vectors of important parasitic and arboviral diseases. AgNPs showed higher toxicity if compared to the H. ada-kodien leaf aqueous extract, LC50 towards larvae of A. stephensi, A. aegypti, and C. quinquefasciatus were 12.18, 13.30, and 14.70 μg/ml, respectively. AgNPs tested on non-target water bugs, Diplonychus indicus, LC50 value was 623.48 μg/ml. Furthermore, 100 μl/ml of AgNPs achieved significant antimicrobial activity against Bacillus pumilus, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris, and Candida albicans. Light and confocal laser scanning microscopy highlighted a major impact of the H. ada-kodien-synthesized AgNPs on the external topography and architecture of microbial biofilms for both Gram-positive and Gram-negative bacteria. Overall, this study sheds light on the insecticidal and antibiofilm potential of H. ada-kodien-synthesized AgNPs, a potential green resource for the rapid synthesis of polydispersed, cluster-shaped, and highly stable AgNPs.

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