Antibacterial and Larvicidal Activity of Biologically Synthesized Silver Nanoparticles from Bambusa arundinaceae Leaves Extract

The increased morbidity and mortality due to the resistance developed in the pathogenic microorganism against antibiotic drugs and mosquito-borne diseases is an emerging issue in medical research. We need to find the new antimicrobial compound and effective biocontrol agent to reduced transmission of pathogenic infection. Due to diverse chemical and mechanical properties, silver nanoparticles produced by the green synthesis method are increasing demand for various pharmaceutical activities. In the present study, the aqueous extract of Bambusa arundinaceae leaves were used for the synthesis of silver nanoparticles. The synthesized (Bambusa arundinaceae derived silver nanoparticles) BA-AgNPs were characterized using UV-vis spectroscopy, FTIR, SEM and their antibacterial along with larvicidal potential was evaluated. Antioxidant capacity was measured using the DPPH method. SEM analysis revealed that BA-AgNPs were predominantly spheroidal shape with particle size distribution in a range of 20 - 80 nm. Lower IC₅₀ value (0.71 mg/ml) of biosynthesized AgNPs showed higher antioxidant activity compared to B. arundinaceae leaf extract (0.92 mg/ml) alone. BA-AgNPs were tested against mosquito larvae (Aedes aegypti and Cx. quinquefasciatus) and their mortality was examined. In larvicidal bioassay, biologically synthesized AgNPs were more toxic (LC₉₀ = 50.8 mg/L and 100.8 mg/L) than silver nitrate (LC₉₀ = 79.0 mg/L and 146.0 mg/L) to fourth instars larvae of A. aegypti and Cx. quinquefasciatus respectively. BA-AgNPs demonstrated the highest mortality in fourth instars larvae of A. aegypti then in Cx. quinquefasciatus. The biosynthesized BA-AgNPs showed a strong antimicrobial activity by causing inhibition of growth with a well diffusion assay. BA-AgNPs showed considerably higher antimicrobial activities against Escherichia coli (E.coli) when compared with both AgNO₃ and streptomycin alone. The results of this experiment suggest that biologically synthesized BA-AgNPs are a quite ideal candidate for the development of new antimicrobial drugs. The collective effect of BA-AgNPs with streptomycin was higher as compared to BA-AgNPs alone which indicates the synergistic effect of these components.