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.

A novel approach for the utilisation of fruit waste is attempted in the present investigation. Mangifera indica seed aqueous extract was utilised for green synthesis of silver nanoparticles (AgNPs). The phytoconstituents in the seed acted as reducing and stabilising agent for AgNP formation. UV-Vis, Zeta potential, FT-IR, XRD, TEM, SAED, EDX analysis were used to characterise the green synthesised AgNPs. UV-vis spectra showed characteristic spectra at 450 nm; XRD and SAED confirmed the crystalline nature while TEM revealed the shape to be round and average size was 26.85 nm. FT-IR revealed functional groups like alcohol or phenols, carboxylic acids, ketones, amines, aromatic amines, aliphatic amines, alkyl halides and alkynes which were responsible for AgNP formation. The nanoparticles showed more antibacterial activity than antifungal activity and antibacterial activity towards Gram-negative bacteria was more than Gram-positive bacteria. Dose dependent antioxidant activity (DPPH, SO and ABTS) and dose dependent cytotoxic effect against HeLa, MCF-7 and normal fibroblast cell lines was envisaged. The green synthesised AgNPs exhibited three different bioactivities (3-in-1 system) i.e. dose dependent antimicrobial, antioxidant and cytotoxic activity. Fruit waste can be successfully utilised for silver nanoparticles formation which can be therapeutically useful and effective.

In this study, gold nanoparticles (AuNPs) were synthesised using seed extract of mango (Mangifera indica) which is considered as waste and generally thrown away into the environment. The bioactive molecules in the seed act as reducing agent to synthesise AuNPs without using any external agent. The characterisation of green synthesised AuNPs was done using various spectroscopic techniques. Visual colour change from colourless to ruby red colour confirmed the formation of AuNPs which was further confirmed by maximum absorption peak at 550 nm by UV-spectra. Crystalline nature was confirmed by XRD technique while round, triangle and irregular shape and 19.45 nm size was confirmed by TEM and SAED analysis. FTIR analysis confirmed the presence of alcohol or phenol, carboxylic acid, ketones, amines, aromatic amines, aliphatic amines, alkyl halides and alkynes in M. indica seed which were responsible for the reduction of gold to AuNPs. The green synthesised AuNPs were evaluated for their antimicrobial, antioxidant and cytotoxic potential. They showed moderate antibacterial, cytotoxic and dose-dependent antioxidant activity. Seeds of M. indica instead of discarding can be successfully utilised for AuNPs synthesis which can be used as a natural source of antimicrobial, antioxidant and anticancer agent. Graphical Abstract

Caesalpinia pulcherrima flower extract mediated synthesis of silver nanoparticles was attempted in the present work including optimization of some procedure parameters. Characterization of synthesized silver nanoparticles was done by various spectral analyses. The size of synthesized silver nanoparticles was 12 nm and they were spherical in shape. The green synthesized silver nanoparticles were further evaluated for antimicrobial, antioxidant, cytotoxic, and genotoxic activities; they showed good antimicrobial, antioxidant, and cytotoxic effects. Genotoxic study revealed non-toxic nature at lower concentration. Overall results suggest that the synthesized silver nanoparticles have pronounced applicability in pharmaceutical and biomedical field.

To assess the effects of extraction methods on antioxidant activities of selected Indian medicinal flora. Different parts of plants were extracted by hydroalcoholic and decoction methods using water and various concentrations of methanol (ME) viz. 75%, 50% and 25% ME. The antioxidant activity of all the different extracts was evaluated using two different antioxidant assays viz. 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical scavenging assay and superoxide anion radical scavenging assay. Total phenol and flavonoid content was also estimated. The results showed that the extracting solvent significantly altered the antioxidant property estimations of screened plants. High correlations between phenolic compositions and antioxidant activities of extracts were observed. High levels of antioxidant activities were detected in Manilkara zapota (M. zapota) as compared with other screened plants. The results obtained appear to confirm the effect of different methods on extraction of antioxidants and antioxidant property of M. zapota.

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.