Antibacterial and antioxidant activity of green synthesized Zinc oxide nanoparticles using polyphenol extract from Mentha piperita seeds

In the recent decade, zinc oxide nanoparticles (ZnO NPs) have been widely explored owing to their versatile properties and prodigious demands in the drug delivery, medical, energy storage, cosmetics, and the healthcare sectors. Therefore, the current work opts for an environmentally benign method to prepare ZnO NPs. The leaf extract of Calendula officinalis L. acts as a reducing agent for the metal ions; therefore, in the current research, ZnO NPs were prepared via green route by using Calendula officinalis leaf extract. Furthermore, the ZnO NPs were analysed with different spectroscopic techniques to confirm the structure and stability of nanomaterials. The prepared ZnO NPs were characterized by XRD, FE-SEM, FT-IR and UV–Vis studies. Also, the antioxidant and antimicrobial properties of the synthesized ZnO NPs were investigated. The XRD result of synthesized ZnO NPs showed the crystalline size 28.23 nm with wurtzite hexagonal structure along with the most intense peak (101). Following preliminary confirmations of the intended ZnO NPs, both big and small agglomerated forms were observed in the FE-SEM, which is often used to determine their exterior assembly. Further, the results of Fourier transform infrared spectroscopy (FT-IR) indicated the formation of pure ZnO NPs with an absorption peak of the Zn–O bond between 4000 cm−1 and 500 cm−1 and no discernible peak in the monitoring range. The UV–Vis spectrum of the green synthesized ZnO NPs were revealed two prominent absorption peaks at 355 nm and 370 nm with energy band gap of 2.986 eV. Using the 1, 1-di phenyl-2-picrylhydrazyl (DPPH) test, the antioxidant activity of the described ZnO NPs was assessed. It demonstrated how, ZnO NPs significantly increased their antioxidant activity by scavenging 1, 1-di phenyl-2-picrylhydrazyl (DPPH) free radicals. It could be seen that synthesis of the naturally occurring plant product ZnO NPs have been acting as an alternate of chemical antioxidant. The antimicrobial analysis was also performed with the help of disk diffusion method where three multi-drug resistant human pathogens namely Staphylococcus aureus, Klebsiella pneumoniae and E.coli were used. The Zone of Inhibition diameter values are 35.2 mm ± 0.9, 23.6 mm ± 0.1 and 13.5 mm ± 0.1, respectively, which showed that the ZnO NPs was highly effective against S. aureus. Thus, the green synthesis method of ZnO NPs using leaf extract of Calendula officinalis is evidence that it is superior and environmentally friendly method for the preparation of ZnO NPs and hence it can be utilized in various nano-medicine approaches.

Zinc oxide nanoparticles (ZnO-NPs) have been extensively researched for their potential applications in various fields such as pharmaceuticals, cosmetics, biotechnology, sensing, photocatalysis, and photovoltaics due to their unique nanoscale properties. However, the conventional methods for producing ZnO NPs require the use of hazardous chemicals and high energy consumption, which imposes certain limitations. In contrast, the green synthesis of ZnO-NPs using plant extracts, especially Origanum majorana, has gained much attention as a promising alternative approach. Plant extracts contain phytochemicals that are biologically safe and non-toxic, making them a preferred choice. In addition, the ZnO-NPs synthesized with O. majorana extracts exhibit higher stability and can be customized in terms of shape and size, unlike the ZnO-NPs obtained by bacterial or fungal methods. The aqueous leaf extract of O. majorana contains flavonoids, tannins, and phenolic derivatives, which serve as reducing and capping agents for the biosynthesis of ZnO-NPs. These extracts also contain functional groups such as -OH and -C=O, which further enhance the physicochemical properties of the resulting ZnO-NPs and influence their ability to target specific molecules. The plant-mediated synthesis of ZnO-NPs using O. majorana leaf extract is not only fast and straightforward but also offers a wide range of functionalized nanoparticles with specific morphologies and sizes. These ZnO-NPs prepared with O. majorana have been shown to have potential applications in various fields, including antimicrobial, antioxidant, and anticancer activities. This review focuses specifically on the antimicrobial applications of ZnO-NPs synthesized using O. majorana leaf extract.

Annona muricata belongs to the family Annonaceae and the leaf extract has traditionally been used as an antipyretic, anti-diabetic, antihypertensive, and antimalarial. The study aims to formulate zinc oxide nanoparticles (ZnO NPs) using Annona muricata leaf extract (AME) and evaluate its biological activities. The biosynthesized ZnO NPs were characterized using UV-vis spectroscopy, FTIR, XRD and SEM. GC-MS analysis of AME indicated sesquiterpenes, acetogenins, alkaloids, flavonoids, fatty acids and other compounds. The presence of ZnO NPs was confirmed by the UV-vis absorption spectrum with a peak at 370 nm. XRD and FTIR showed the stabilized ZnO NPs using AME bioactive compounds with an average particle size of 79.14 nm. SEM and EDX revealed spherical and hexagonal morphology. Minimum inhibitory concentration experiments revealed that MIC values for P. aeruginosa and B. subtilis were 1.25mg/mL and 0.32mg/mL, respectively. Antioxidant activities of the AME, AME-ZnO NPs and ascorbic acid (standard) using DPPH assay revealed IC50 values of 2.17mg/mL, 1.66mg/mL and 0.23mg/mL, respectively. The formulated ZnO NPs also aided in the photocatalysis of methylene blue at a degradation rate of 66.8% after 180 min. These results collectively highlight the promising therapeutic potential of A. muricata biogenic zinc oxide nanoparticles for developing future therapies due to antibacterial, photocatalytic and antioxidant activities.

Annona muricata belongs to the family Annonaceae and the leaf extract has traditionally been used as an antipyretic, anti-diabetic, antihypertensive, and antimalarial. The study aims to formulate zinc oxide nanoparticles (ZnO NPs) using Annona muricata leaf extract (AME) and evaluate its biological activities. The biosynthesized ZnO NPs were characterized using UV-vis spectroscopy, FTIR, XRD and SEM. GC-MS analysis of AME indicated sesquiterpenes, acetogenins, alkaloids, flavonoids, fatty acids and other compounds. The presence of ZnONPs was confirmed by the UV-vis absorption spectrum with a peak at 370 nm. XRD and FTIR showed the stabilized ZnO NPs using AME bioactive compounds with an average particle size of 79.14 nm. SEM and EDX revealed spherical and hexagonal morphology. Minimum inhibitory concentration experiments revealed that MIC values for P. aeruginosa and B. subtilis were 1.25mg/mL and 0.32mg/mL, respectively. Antioxidant activities of the AME, AME-ZnO NPs and ascorbic acid (standard) using DPPH assay revealed IC50 values of 2.17mg/mL, 1.66mg/mL and 0.23mg/mL, respectively. The formulated ZnO NPs also aided in the photocatalysis of methylene blue at a degradation rate of 66.8% after 180 min. These results collectively highlight the promising therapeutic potential of A. muricata biogenic zinc oxide nanoparticles for developing future therapies due to antibacterial, photocatalytic and antioxidant activities.

Cytotoxicity of green synthesized zinc oxide nanoparticles using Musa acuminata on Vero cells

Bacterial infections remain a critical global health concern, often leading to prolonged self-medication, extended healing times, treatment failures, increased hospitalization, and higher healthcare costs, alongside increased mortality rates. Recent research efforts have focused on enhancing human health and environmental sustainability through innovative synthesis techniques. This study presents a straightforward and cost-effective method for the green synthesis of zinc oxide nanoparticles (ZnO NPs) using fruit extract from Washingtonia robusta H. Wendl and investigated their antibacterial activity. The W. robusta fruit extract underwent high-performance liquid chromatography (HPLC), resulting in the isolation of four distinct fractions that were tested for antibacterial activity against various Gram-positive and Gram-negative bacteria. The methanolic fraction demonstrated the highest antibacterial potential and was analyzed for bioactive compounds using gas chromatography-mass spectrometry. This analysis identified ten biochemical constituents, including hexasiloxane (43.28%), E-9-tetradecenoic acid (12.99%), oleic acid (10.12%), and heptasiloxane (9.83%). The ZnO NPs using methanolic fraction and characterized using various techniques, including ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, zeta potential analysis, and transmission electron microscopy. The antibacterial efficacy of the ZnO NPs was evaluated against Escherichia coli ATCC25922, and Bacillus cereus ATCC6633. The antibacterial activity was assessed. Results indicated that the ZnO NPs exhibited a good antibacterial activity with average inhibition zones 18 mm against E. coli, and 24 mm against B. cereus. The MIC values for ZnO NPs were 35 µg/ml against E. coli and 25 µg/ml against B. cereus. The MBC values matched with MIC results that indicated the potent bactericidal action of the prepared ZnO NPs.

In an era of eco-friendly development, the green synthesis of metal nanoparticles using plant extracts has become a focus of researcher attention. The present work introduces method of a green synthesis of Zinc oxide nanoparticles (G ZnO NPs) using orange peel extract and their size and morphology were examined using high resolution transmission electron microscope (HRTEM). Additionally, its impact in comparison with chemically synthesized Zinc oxide nanoparticles (C ZnO NPs) was examined on females, nymphs and larvae of stored grain mites Caloglyphus mycophagous (Megnin) and Mycetoglyphus fungivorus Oudemans. Stored mites are responsible for notable losses of cereals including wheat, rice, soybeans and maize which are among the essential agricultural goods that contribute to the bulk of a global food security basis. Three different concentrations of both types of ZnO NPs (10, 30 and 60 ppm) were utilized. The mortality rate (%) was recorded after 24, 48, 72 and 96 hour (h) post-exposure to each tested concentration. The results of high-resolution transmission electron microscope showed that the size of C and G ZnO NPs were 35 and 3 nm, respectively. Both types of ZnO NPs showed toxicity against tested stages and the mortality rates were increased by concentration and exposure time increase. Chemical ZnO NPs was more effective than G ZnO NPs to all stages of mites post -initial exposures, and then all had the same effect by passing time. Females and nymphs of both tested mites recorded 100% mortality after 72h post-exposure to 60 ppm of both ZnO NPs, while larvae of M. fungivorus recorded this mortality percentage after 24h post-exposure to all tested concentrations of each ZnO NPs except with G ZnO NPs at 10ppm, the mortality was (90%). The same result (100%) was observed in C. mycophagous larvae after 48h post-exposure. The deposited eggs by treated females of each mite were highly significantly decreased and did not hatch at all. Strong adherences of tested ZnO NPS were visualized clearly attached to different parts of dead females by images of Scanning Electron Microscopy (SEM). The result of this work suggests that G ZnO NPs are effective candidate agents against storage mites.

Green synthesized nanoparticles are believed to alleviate the detrimental effects of chemical fertilizers and the multidrug resistance of various microbial strains. This study evaluates the use of bush tea-mediated zinc oxide nanoparticles (ZnO NPs) for chickpea fertilization and assesses their cytotoxicity, antioxidant and antibacterial activity. The study demonstrated that the application of ZnO NPs improved the number of leaves, nodules, biomass and yield of chickpea cultivars under glasshouse conditions. The authors suggest that biosynthesized ZnO NPs are a good plant growth stimulant. The control with no nanoparticles application, had higher values of photosynthetic rate and water use efficiency in the Desi genotype whereas for the Kabuli genotype, 25 mg/L showed higher values of stomatal conductance and transpiration efficiency, while 15 mg/L gave the highest water use efficiency and photosynthetic rate. Furthermore, the inhibitory activities of bacteria were reported in which E. coli and S. aureus were the most sensitive bacterial strains. The ZnO NPs also quenched free radicals that demonstrate antioxidant activity. Thus, they can be beneficial to both plants and humans as they reduce oxidative stress that can cause diseases. Furthermore, toxicity to cells was evaluated and ZnO NPs were less toxic to the studied cells with IC50 values of 16.17 µg/mL and 21.30 µg/mL against lung cancer and embryonic cell lines. Thus, the use of ZnO nanoparticles with antimicrobial activity could help fight against several diseases attacking humans and plants.

Zinc oxide Nanoparticles, Biosynthesis, characterization and their potent photocatalytic degradation, and antioxidant activities

With an increasing focus on the application of nanoparticles in the field of research, this study aims to evaluate the in-vitro antibacterial properties of chemically and green synthesized zinc oxide nanoparticles (ZnO NPs) from two plant sources Delonix elata and Gynura cusimbua. The bioactive compounds present in the leaf extracts were utilized to stabilize the nanoparticles. UV-Visible spectrophotometry (UV-Vis), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) were used to elucidate the optical and structural properties of the synthesized ZnO NPs. The in-vitro antibacterial potential of ZnO NPs were evaluated by Agar Disc Diffusion Assay against two pathogenic bacterial strains: Bacillus cereus, a gram-positive animal pathogen and Pseudomonas syringae, a gram-negative plant pathogen, making it a well-rounded approach. The UV–visible spectrum was measured in 250 – 400 nm range and the crystallite structure was analyzed via XRD. SEM-EDS (Energy-Dispersive X-ray Spectroscopy) analysis confirmed the nanostructures with partial nanoflakes and aggregates for all three samples of the synthesized ZnO NPs. The D. elata ZnO NPs showed relatively greater antimicrobial activity against both the bacterial strains than that of G. cusimbua ZnO NPs. Consequently, plant-based NPs may be an excellent strategy for developing versatile and environmentally friendly biomedical products. They have an added advantage due to their pre-existing medicinal properties, which make them a more suitable alternative to the broadly used chemically synthesized nanoparticles. KEY WORDS: Delonix elata, Gynura cusimbua, Zinc oxide Nanoparticle, antimicrobial activity, Bacillus cereus, Pseudomonas syringae.

This study aimed to assess the apoptosis-inducing mechanism of zinc oxide nanoparticles (ZnO NPs) stabilized by Solanum xanthocarpum plant extract in human osteosarcoma MG63 cells. In the present study, we synthesized ZnO NPs from S. xanthocarpum extract and evaluated its anticancer mechanism on MG 63 cells. The synthesized ZnO NPs were characterized by ultraviolet spectroscopy, X-ray crystallography, transmission electron microscopy, energy dispersive X-ray, and Fourier-transform infrared spectroscopy analysis. The mean size of the synthesized ZnO NPs was 21.62 ± 7.45 nm and spherical in shape. The cytotoxicity of ZnO NPs on MG63 cells was determined by MTT assay. The Western blot analysis was carried out to examine the expression of apoptotic and autophagy-related proteins in MG63 cells. The findings of the study reveal that ZnO NPs treatment showed concentration-dependent cytotoxicity, increased lipid peroxidation, decreased antioxidant activity, increased reactive oxygen species generation, and increased DNA damage. In addition, ZnO NPs treatment increased the expression of apoptotic members such as p53, Bax, caspase-3, -8, and -9 while downregulating Bcl-2 expression in MG63 cells. Furthermore, ZnO NPs treatment suppressed the P13K/AKT/mTOR signaling pathway and increased the expression of LC3 and beclin-1 in MG63 cells. The present study demonstrated that ZnO NPs induced apoptosis and autophagy in MG63 cells through modifying apoptotic and autophagy-related proteins.

Nanotechnology is a fast-growing field with diverse applications in various disciplines. Based on the applications in diverse fields and the medicinal significance, R. roseum was phytochemically investigated and was used for the synthesis of zinc oxide nanoparticles (ZnO-NPs). Biosynthesized NPs were characterized using UV spectrophotometry (UV), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM), and used in antioxidant, antibacterial, and seed nano priming activities. Antibacterial activity was observed against Klebsiella pneumoniae, Bacillus subtilis, Enterococcus faecalis, and Staphylococcus aureus, with the maximum zone of inhibition recorded against S. aureus (23mm ± 0.57) at 1000µg/ml. ZnO-NPs exhibited the highest antioxidant activity (75.2%) at 100µg/mL in comparison with the standard (ascorbic acid), which showed 79% activity at the same concentration. The IC50 value of R. roseum-mediated ZnO-NPs obtained was 35.79 at a 20µg/mL ZnO-NP concentration. Seed priming with R. roseum-mediated ZnO NPs markedly enhanced maize growth, with the highest performance recorded at 200ppm, yielding 3.33 ± 0.40g fresh weight, 3.20 ± 0.1g dry weight, and 6 ± 1 leaves. At this concentration, seedlings also exhibited increased root (13.5 ± 0.57mm) and shoot length (12.6 ± 0.57cm) along with elevated chlorophyll content (34.9 ± 4.57), indicating significant improvement in physiological attributes. Compared to the control, nanoparticle treatment at 50µg/mL increased peroxidase activity from 18.4 to 31.3 U mg⁻1 protein, superoxide dismutase from 22.6 to 36.9 U mg⁻1 protein, and catalase from 15.2 to 27.8 U mg⁻1 protein. In conclusion, green-synthesized ZnO-NPs are effective and can be utilized in agriculture, biomedical, and other fields.

This study aimed to investigate the characterization of zinc oxide nanoparticles (ZnONPs) produced from Cucurbita pepo L. (pumpkin seeds) and their selective cytotoxic effectiveness on human colon cancer cells (HCT 116) and African Green Monkey Kidney, Vero cells. The study also investigated the antioxidant activity of ZnONPs. The study also examined ZnONPs' antioxidant properties. This was motivated by the limited research on the comparative cytotoxic effects of ZnO NPs on normal and HCT116 cells. The ZnO NPs were characterized using Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Transmission Electron Microscope/Selected Area Electron Diffraction (TEM/SAED), and Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) for determination of chemical fingerprinting, heat stability, size, and morphology of the elements, respectively. Based on the results, ZnO NPs from pumpkins were found to be less than 5 μm and agglomerates in nature. Furthermore, the ZnO NPs fingerprinting and SEM-EDX element analysis were similar to previous literature, suggesting the sample was proven as ZnO NPs. The ZnO NPs also stable at a temperature of 380°C indicating that the green material is quite robust at 60-400°C. The cell viability of Vero cells and HCT 116 cell line were measured at two different time points (24 and 48 h) to assess the cytotoxicity effects of ZnO NP on these cells using AlamarBlue assay. Cytotoxic results have shown that ZnO NPs did not inhibit Vero cells but were slightly toxic to cancer cells, with a dose-response curve IC50 = ~409.7 μg/mL. This green synthesis of ZnO NPs was found to be non-toxic to normal cells but has a slight cytotoxicity effect on HCT 116 cells. A theoretical study used molecular docking to investigate nanoparticle interaction with cyclin-dependent kinase 2 (CDK2), exploring its mechanism in inhibiting CDK2's role in cancer. Further study should be carried out to determine suitable concentrations for cytotoxicity studies. Additionally, DPPH has a significant antioxidant capacity, with an IC50 of 142.857 μg/mL. RESEARCH HIGHLIGHTS: Pumpkin seed extracts facilitated a rapid, high-yielding, and environmentally friendly synthesis of ZnO nanoparticles. Spectrophotometric analysis was used to investigate the optical properties, scalability, size, shape, dispersity, and stability of ZnO NPs. The cytotoxicity of ZnO NPs on Vero and HCT 116 cells was assessed, showing no inhibition of Vero cells and cytotoxicity of cancer cells. The DPPH assay was also used to investigate the antioxidant potential of biogenic nanoparticles. A molecular docking study was performed to investigate the interaction of ZnO NPs with CDK2 and to explore the mechanism by which they inhibit CDK2's role in cancer.

Multifaceted applications of chitosan-L-ornithine modified ZnO nanoparticles: Antibacterial, antioxidant, and anticancer potentials

PurposeTo study the cytotoxic evaluation, antimicrobial and confocal analysis of zinc oxide nanoparticles (ZnO NPs) obtained from a novel plant product fennel (Foeniculum vulgare Mill.) seed extract (FSE).MethodsZnO NPs were analyzed using UV–Vis spectroscopy, XRD, FTIR, TEM and EDX techniques. The MTT cell cytotoxicity assay measured the proliferation and survival of MCF-7 cells treated at different concentrations of FSE-derived ZnO NPs. The antimicrobial activity towards pathogenic bacteria and yeast strains was investigated.ResultsThe UV–Vis spectra showed two peaks at 438 nm and 446 nm, confirming nanoparticle formation. The SEM morphology results showed porous ranging from 23–51 nm. The antitumor activity value (IC50) was at 50 µg/mL and 100 µg/mL. Besides, morphological changes of MCF-7, cells treated at different concentrations of FSE of ZnO NPs were observed in cell cultures transfected with a transient pCMV6-XL4-GFP-expressing vector containing C-terminal domain GFP-tagged proteins, which resulted in an apoptotic effect. Antimicrobial IZ ranged up No Inhibition to 18.00 ± 0.4. The IZ revealed at the highest concentration was E. faecium VRE and yeast Cryptococcus sp. (18.00 ± 0.4. mm), followed by S. aureus (17.00 ± 0.2 mm) and P. aeruginosa and the yeast C. parapsilosis (16 ± 0.4 mm). The IZ was equal to that caused by the nystatin to Cryptococcus sp., which was significantly highest than ampicillin treatments of S. aureus, P. aeruginosa, C. albicans, and C. parapsilosis. The MIC value of the FSE-derived ZnO NPs tested against E.faecium and C.albicans was 6.00 µg/mL (E. faecium and C. albicans). It was 32.00 µg/mL (S. aureus, S. typhimurium and Cryptococcus sp.), 64.00 µg/mL (P. aeruginosa), and 128 µg/mL (C. parapsilosis).ConclusionAs far as it is to our knowledge, this study established, for the first time, the biological activities of biosynthesized ZnO NPs from FSE and their synergistic therapeutic potential.