Antimicrobial efficacy of phyto-synthesized silver nanoparticles using aqueous leaves extract of Rosamarinus officinalis L.

The current research investigation demonstrated that the aqueous leaves extract of Rosamarinus officinalis possesses cardinal phyto-chemicals to fabricate AgNPs in an eco-friendly way. The phyto-synthesized AgNPs were characterized to be stable, monodispersed, polycrystalline and mostly spheroidal in conformation. The nano-spheriods were observed to be 25-75 nm in diameter, displaying λmax peak at 430 nm. From the comparative antimicrobial investigations, it was observed that AgNPs manifested tremendous bactericidal properties against all test organisms particularly S. epidermis (89%), S. aureus (84%) and K. pneumonia (84%), owing least MIC values of 40µL. The aced fungicidal activity was also exhibited by AgNPs against all fungal test species particularly C. herbarum (90%), A. flavus (85%), R. stolonifer (85%) and C. jadinii (85%). In contrast to AgNPs, all crude ethanolic, aqueous, methanolic and n-hexanoic extracts manifested less to moderate antimicrobial activity against all test micro-organisms with three-fold escalating MIC values i.e., 160µL.

Synthesis, characterization and biological investigation of zinc nanoparticles using Acacia modesta Wall. leaves.

The study aimed to synthesize zinc nanoparticles (Zn-NPs) using an aqueous extract derived from Acacia modesta Wall. leaves. Several characterization techniques were employed to confirm the successful formation of zinc nanoparticles. UV-visible spectrophotometry indicated a peak at 374 nm, validating the bioreduction process. Scanning electron microscopy (SEM) was utilized to analyze the morphology, transmission electron microscopy (TEM) to determine particle size and shape, X-ray diffraction (XRD) for crystalline structure analysis, energy-dispersive X-ray spectroscopy (EDX) for elemental composition and Fourier-transform infrared spectroscopy (FTIR) to identify functional groups. The synthesized Zn-NPs demonstrated remarkable antibacterial activity against Escherichia coli (95% inhibition) and moderate antifungal activity against Candida albicans (70% inhibition). In phytotoxicity tests, the Zn-NPs exhibited a 55% reduction in the growth of Lamina minor at the highest dilution (1000 µl). Based on these findings, the study concluded that the green-synthesized Zn-NPs hold great potential as effective antibiotics against pathogenic bacteria and could be utilized in various industrial and agricultural applications.

Phyto-fabrication, purification, characterisation, optimisation, and biological competence of nano-silver.

Published studies indicate that virtually any kind of botanical material can be exploited to make biocompatible, safe, and cost-effective silver nanoparticles. This hypothesis is supported by the fact that plants possess active bio-ingredients that function as powerful reducing and coating agents for Ag+. In this respect, a phytomediation method provides favourable monodisperse, crystalline, and spherical particles that can be easily purified by ultra-centrifugation. However, the characteristics of the particles depend on the reaction conditions. Optimal reaction conditions observed in different experiments were 70-95 °C and pH 5.5-8.0. Green silver nanoparticles (AgNPs) have remarkable physical, chemical, optical, and biological properties. Research findings revealed the versatility of silver particles, ranging from exploitation in topical antimicrobial ointments to in vivo prosthetic/organ implants. Advances in research on biogenic silver nanoparticles have led to the development of sophisticated optical and electronic materials with improved efficiency in a compact configuration. So far, eco-toxicity of these nanoparticles is a big challenge, and no reliable method to improve the toxicity has been reported. Therefore, there is a need for reliable models to evaluate the effect of these nanoparticles on living organisms.

Green synthesis, characterisation and biological evaluation of AgNPs using Agave americana, Mentha spicata and Mangifera indica aqueous leaves extract.

The current study was performed to synthesize stable, eco-friendly and bio-compatible silver nano-particles (AgNPs) of Agave americana, Mentha spicata and Mangifera indica leaves and to screen them for biological activities. The ultraviolet-visible spectroscopic analysis revealed that λ-max for AgNPs range from 350-500 nm. All AgNPs possessed polycrystalline structure as notified as intense graphical peaks in complete spectrum of 20 values ranging from 10-80° in X-ray diffraction measurements and supported by scanning electron microscopy data. The size of the nano-particles was confirmed by transmission electron microscopy (30-150 nm). Mass loss at variable temperatures was evaluated by simultaneous thermogravimetric and differential thermal analysis revealed reduction in mass and activity of compounds was notified by temperature increase from 200 to 800 °C, thus concluding it as thermally sensitive compounds. A. americana AgNPs showed significant (96%) activity against Methicillin resistant Staphylococcus aureus, Escherichia coli (95%) and Fusarium oxysporum (89%). Good antioxidant activity was shown by M. spicata AgNPs at 300 µl (79%). M. indica AgNPs showed significant phytotoxic activity (88%) at highest concentration. No haemagglutination reaction was observed for the test samples. The above results revealed that AgNPs synthesized from selected plant species possesses significant antimicrobial and phytotoxic effect.