In the present study, silver nanoparticles were synthesized using flower broth of Tagetes erecta as reductant by a simple and eco-friendly route. The aqueous silver ions when exposed to flower broth were reduced and resulted in green synthesis of silver nanoparticles. The silver nanoparticles were characterized by UV-visible spectroscopy, zeta potential, Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction, Transmission electron microscopy (TEM) analysis, Energy dispersive X-ray analysis (EDX) and selected area electron diffraction (SAED) pattern. UV-visible spectrum of synthesized silver nanoparticles showed maximum peak at 430 nm. TEM analysis revealed that the particles were spherical, hexagonal and irregular in shape and size ranging from 10 to 90 nm and Energy dispersive X-ray (EDX) spectrum confirmed the presence of silver metal.

Zinc oxide nanoparticles (ZnO NPs) were synthesized using Ziziphus nummularia leaf extract. The characterization was done by various spectral analysis and antifungal (anti-candidal) activity against multidrug resistant clinical isolates and their cytotoxic potential was evaluated. The ZnO NPs were 17.33 nm in size and were spherical/irregular in shape. The antifungal activity of ZnO NPs was better than four standard azole antibiotics and they also showed potent cytotoxic effect against HeLa cancer cell line. The results strongly suggest the applicability of green synthesized ZnO NPs as antifungal agent and also its use in cancer diagnosis and treatment.

Bacteria have evolved numerous defences against antimicrobial agent and drug resistance in pathogen is on rise. This is due to rapid development of multi-drug resistance, limited anti-bacterial spectrum and adverse effects of available anti-microbial agents. This necessitates the search for new antimicrobials with diverse structures and novel mechanism of action. Flowers are mostly used for ornamental purposes and they are not frequently worked out hence marigold flower was selected for the study. The antimicrobial activity of different solvent (Hexane, Toluene, Ethyl acetate, Acetone, Methanol and Aqueous) extracts of marigold flowers were evaluated by agar well diffusion method against a panel of pathogenic microorganisms. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of acetone extract and its fraction were evaluated. B. cereus and K. pneumonia were the most sensitive organisms to acetone extract and minimum inhibitory concentration (MIC) was 78 µg/ml. Synergistic effect of acetone extract and commercial antibiotics (chloroamphenicol and ceftazidime) against pathogenic bacteria was investigated. The best synergistic activity was with combination of acetone extract and ceftazidime against B. subtilis and P. aeruginosa with FIC indices 0.312 and 0.093 respectively. Only the polar solvent acetone extract showed promising antibacterial and synergistic activity. These results indicate that combination between plant extract and the antibiotics could be useful in fighting emerging drug-resistant microorganisms and choice of the solvent plays a prominent role in evaluating antimicrobial activity of medicinal plants. Flowers can be taken as an alternative source of antimicrobial agent against the human pathogens.

In this work, we report for the first time, synthesis of silver nanoparticles using Cassia roxburghii leaf extract and evaluate its synergistic antibacterial efficacy and antioxidant potential. The synergistic antimicrobial activity of silver nanoparticles with commercial antibiotics against Gram-positive, Gram-negative bacteria and fungi was evaluated. The antioxidant potential of synthesized silver nanoparticles was evaluated by FRAP and ABTS radical scavenging antioxidant assays. UV–Vis spectra peak at 473 and color change from colorless to brown color confirmed the formation of AgNPs. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern confirmed the crystalline nature of synthesized nanoparticles. Transmission electron microscopy (TEM) analysis revealed the average size of particles to be 15–20 nm. Fourier transform infrared spectroscopy (FTIR) revealed the functional groups C. roxburghii leaf that was responsible for the reduction and capping process of nanoparticles. C. roxburghii leaf extract synthesized AgNPs showed good synergistic antimicrobial against Gram-negative bacteria even better than some of the antibiotics used as positive control; they also showed antioxidant potential. The results suggest that the synthesized nanoparticles can be used to treat multidrug resistant microorganisms and stress related diseases and disorders.

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