Biosynthesis of Bixa orellana seed extract mediated silver nanoparticles with moderate antioxidant, antibacterial and antiproliferative activity

Biosynthesis of metallic silver nanoparticles (AgNPs) has gained much interest and offers an attractive alternate to physical and chemical approaches. In recent year several safe, easy, cost-effective, reproducible, and environmentally friendly synthesis approaches for silver nanoparticles have been developed. In this research work, a simple, cheap, and unexplored method was applied on green synthesis of AgNPs using secondary metabolites extracted from Bixa orellana seeds. The seeds are rich of flavonoids and phenolic compounds which presumably responsible for the fast reduction and stabilization of silver ion into silver nanoparticles. The biosynthesis process is very likely to be able to reduce silver ions under simple physiological conditions. The surface plasmon resonance (SPR) that was appeared at 420 nm in UV–vis spectrum, had confirmed the formation of AgNPs. Moreover, the functional groups in secondary metabolite that act as reducing, capping and stabilizing agents for silver nanoparticles, are identified by Fourier transform infrared (FTIR) spectra. An X-ray diffraction analysis generated four peaks for Bixa orellana seed extract mediated AgNPs positioned at 2θ angles of 38.1°, 44.2°, 64.6°, and 77.5° corresponding to crystal planes (111), (200), (220), and (311). Field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nanosized silver particles. The z-average of the synthesized particles measured by dynamic light scattering (DLS) was found to be 92.9 nm. AgNPs synthesized exhibited remarkable antioxidant activity, antibacterial and antiproliferative activity against human breast (MCF-7) cell line. On the basis of our results, we conclude that biologically synthesized AgNPs exhibited favorable characteristics and have the potential to be used in biomedical fields

Salicylic Acid Improves Agro-Morphology, Yield and Ion Accumulation of Two Wheat (<i>Triticum aestivum</i> L.) Genotypes by Ameliorating the Impact of Salt Stress

Wheat growth, development and yield are severely affected by a wide range of abiotic stresses, and salt stress is a vital and increasing abiotic stress. Salicylic acid (SA) is a phenolic phytohormone involved in plant physiological processes. Hence, we have conducted an experiment to explore the roles of exogenous SA in mitigating salt stress in two wheat genotypes. There were eight treatments comprising (i) control, (ii) 0.5 mM SA, (iii) 1.0 mM SA, (iv) 1.5 mM SA, (v) salinity (12 dS m−1), (vi) salinity + 0.5 mM SA, (vii) salinity + 1.0 mM SA and (viii) salinity + 1.5 mM SA with two wheat genotypes viz G 200-4 and BARI gom-25. The experiment was laid out in a completely randomized design with five replications. During the vegetative stage, salt stress significantly reduced the relative water content (RWC), photosynthetic rate, stomatal conductance and growth characteristics of both wheat genotypes, while the exogenous application of SA in salt-stressed plants significantly improved the RWC, gas exchange activities and growth performance of both the genotypes. The leaf chlorophyll content was also degraded due to salinity treatment, although it was mitigated by the exogenous application of SA. The imposition of salt significantly reduced the number of days required for maturity, yield-contributing characteristics and the yield of both the wheat genotypes. Salt stress also significantly increased Na+ concentrations and the Na+/K+ ratio, while the K+ concentrations was decreased significantly in both the wheat genotypes. However, the exogenous application of SA in salt-stressed plants significantly reduced the salt stress effects and increased the growth and yield of wheat genotypes by enhancing RWC, gas exchange activities and photosynthetic pigments and maintaining lower Na+ concentrations and a Na+/K+ ratio. Therefore, the findings of this study suggested that the exogenous application of SA improved the salt tolerance of both wheat genotypes