Arivarasan Vishnu Kirthi

Green synthesis of titanium dioxide nanoparticles using Psidium guajava extract and its antibacterial and antioxidant properties

OBJECTIVE To determine the efficacies of antibacterial and antioxidant activities of aqueous leaf extract of Psidium guajava mediated biosynthesis of titanium dioxide nanoparticles (TiO2 NPs). METHODS Synthesized TiO2 NPs were tested by disc diffusion method against against human pathogenic bacteria. The total antioxidant activity and phenolic content (Folin-Ciocalteau method) of synthesized TiO2 NPs and aqueous plant extract were determined. The scavenging radicals were estimated by DPPH method. The synthesized TiO2 NPs were characterized by XRD, FTIR, FESEM and EDX. RESULTS FTIR spectra of synthesized TiO2 NPs exhibited prominent peaks at 3 410 cm(-1) (alkynes), 1 578 cm(-1), 1 451 cm(-1) (alkanes), and 1 123 cm(-1)(C-O absorption). The morphological characterization of synthesized TiO2 NPs was analysed by FESEM which showed spherical shape and clusters with an average size of 32.58 nm. The maximum zone of inhibition was observed in the synthesized TiO2 NPs (20 μg/mL) against Staphylococcus aureus (25 mm) and Escherichia coli (23 mm). The synthesized TiO2 NPs showed more antibacterial activity than the standard antibiotic disk, tetracycline which drastically reduces the chances for the development of antibiotics resistance of bacterial species. The plant aqueous extract and synthesized TiO2 NPs were found to possess maximum antioxidant activity when compared with ascorbic acid. The content of phenolic compounds (mg/g) in leaf aqueous extract and synthesized TiO2 NPs were found to be 85.4 and 18.3 mgTA/g, respectively. CONCLUSIONS Green synthesized TiO2 NPs provides a promising approach can satisfy the requirement of large-scale industrial production bearing the advantage of low-cost, eco-friendly and reproducible.

Biological approach to synthesize TiO2 nanoparticles using Aeromonas hydrophila and its antibacterial activity

Nanosized materials have been an important subject in basic and applied sciences. A novel, low-cost, green and reproducible bacteria, Aeromonas hydrophila mediated biosynthesis of titanium dioxide nanoparticles (TiO2 NPs) was reported. The resulting nanoparticles were characterized by FTIR, XRD, AFM and FESEM with EDX. FTIR showed characteristic bands (1643 and 3430 cm(-1)) finds the role of carboxyl group OH stretching amine NH stretch in the formation of TiO2 NPs. The XRD spectrum confirmed that the synthesized TiO2 NPs were in the form of nanocrystals, as evidenced by the peaks at 2θ values of 27.47°, 31.77°, 36.11°, 41.25°, 54.39°, 56.64° and 69.54° were identified as 110, 100, 101, 111, 211, 220 and 301 reflections, respectively. The crystallite sizes were calculated using Scherrers formula applied to the major intense peaks and found to be the size of 40.50 nm. The morphological characterization was analyzed by FESEM and the analysis showed the NPs smooth shaped, spherical and uneven. GC-MS analysis showed the main compounds found in A. hydrophila were uric acid (2.95%), glycyl-L-glutamic acid (6.90%), glycyl-L-proline (74.41%) and L-Leucyl-D-leucine (15.74%). The potential glycyl-L-proline could have played an important role as a capping agent. A possible mechanism for the biosynthesis of TiO2 NPs has been proposed. The antibacterial activity of the synthesized TiO2 NPs was assessed by well diffusion method toward A. hydrophila, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis and showed effective inhibitory activity against S. aureus (33 mm) and S. pyogenes (31 mm).

Evaluation of stem aqueous extract and synthesized silver nanoparticles using Cissus quadrangularis against Hippobosca maculata and Rhipicephalus (Boophilus) microplus

The present study was to determine the efficacies of anti-parasitic activities of synthesized silver nanoparticles (Ag NPs) using stem aqueous extract of Cissus quadrangularis against the adult of hematophagous fly, Hippobosca maculata (Diptera: Hippoboscidae), and the larvae of cattle tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). Contact toxicity method was followed to determine the potential of parasitic activity. Twelve milliliters of stem aqueous extract of C. quadrangularis was treated with 88 ml of 1mM silver nitrate (AgNO(3)) solution at room temperature for 30 min and the resulting solution was yellow-brown color indicating the formation extracellular synthesis of Ag NPs. The synthesized Ag NPs were characterized with UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) spectroscopy. The synthesized Ag NPs were recorded by UV-visible spectrum at 420 nm and XRD patterns showed the nanoparticles crystalline in nature. FTIR analysis confirmed that the bioreduction of Ag((+)) ions to Ag NPs were due to the reduction by capping material of plant extract. FESEM image of Ag NPs showed spherical and oval in shape. By using the Braggs Law and Scherrers constant, the average mean size of synthesized Ag NPs was 42.46 nm. The spot EDX analysis showed the complete chemical composition of the synthesized Ag NPs. The mortality obtained by the synthesized Ag NPs from the C. quadrangularis was more effective than the aqueous extract of C. quadrangularis and AgNO(3) solution (1 mM). The adulticidal activity was observed in the aqueous extract, AgNO(3) solution and synthesized Ag NPs against the adult of H. maculata with LC(50) values of 37.08, 40.35 and 6.30 mg/L; LC(90) values of 175.46, 192.17 and 18.14 mg/L and r(2) values of 0.970, 0.992 and 0.969, respectively. The maximum efficacy showed in the aqueous extract, AgNO(3) solution and synthesized Ag NPs against the larvae of R. (B.) microplus with LC(50) values of 50.00, 21.72 and 7.61 mg/L; LC(90) values of 205.12, 82.99 and 22.68 mg/L and r(2) values of 0.968, 0.945 and 0.994, respectively. The present study is the first report on antiparasitic activity of the experimental plant extract and synthesized Ag NPs. This is an ideal eco-friendly and inexpensive approach for the control of H. maculata and R. (B.) microplus.

Acaricidal activity of synthesized titanium dioxide nanoparticles using Calotropis gigantea against Rhipicephalus microplus and Haemaphysalis bispinosa.

OBJECTIVE To assess the acaricidal activity of titanium dioxide nanoparticles (TiO2 NPs) synthesized from flower aqueous extract of Calotropis gigantea(C. gigantea) against the larvae of Rhipicephalus (Boophilus) microplus [R. (B.) microplus] and the adult of Haemaphysalis bispinosa (H. bispinosa). METHODS The lyophilized C. gigantea flower aqueous extract of 50 mg was added with 100 mL of TiO(OH)2 (10 mM) and magnetically stirred for 6 h. Synthesized TiO2 NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectroscopy (EDX). The synthesised TiO2 NPs were tested against the larvae of R. (B.) microplus and adult of H. bispinosa were exposed to filter paper impregnated method. RESULTS XRD confirmed the crystalline nature of the nanoparticles with the mean size of 10.52 nm. The functional groups for synthesized TiO2 NPs were 1 405.19, and 1 053.45 cm(-1) for -NH2 bending, primary amines and amides and 1 053.84 and 1 078.45 cm(-1) for C-O. SEM micrographs of the synthesized TiO2 NPs showed the aggregated and spherical in shape. The maximum efficacy was observed in the aqueous flower extract of C. gigantea and synthesized TiO2 NPs against R. (B.) microplus (LC50=24.63 and 5.43 mg/L and r(2)=0.960 and 0.988) and against H. bispinosa (LC50= 35.22 and 9.15 mg/L and r(2) = 0.969 and 0.969), respectively. CONCLUSIONS The synthesized TiO2 NPs were highly stable and had significant acaricidal activity against the larvae of R. (B.) microplus and adult of H. bispinosa. This study provides the first report of synthesized TiO2 NPs and possessed excellent anti-parasitic activity.

Antimalarial activities of medicinal plants traditionally used in the villages of Dharmapuri regions of South India.

ETHNOPHARMACOLOGICAL RELEVANCE An ethnopharmacological investigation of medicinal plants traditionally used to treat diseases associated with fevers in Dharmapuri region of South India was undertaken. Twenty four plants were identified and evaluated for their in vitro activity against Plasmodium falciparum and assessed for cytotoxicity against HeLa cell line. AIM OF THE STUDY This antimalarial in vitro study was planned to correlate and validate the traditional usage of medicinal plants against malaria. MATERIALS AND METHODS An ethnobotanical survey was made in Dharmapuri region, Tamil Nadu, India to identify plants used in traditional medicine against fevers. Selected plants were extracted with ethyl acetate and methanol and evaluated for antimalarial activity against erythrocytic stages of chloroquine (CQ)-sensitive 3D7 and CQ-resistant INDO strains of Plasmodium falciparum in culture using the fluorescence-based SYBR Green I assay. Cytotoxicity was determined against HeLa cells using MTT assay. RESULTS Promising antiplasmodial activity was found in Aegle marmelos [leaf methanol extract (ME) (IC(50)=7 μg/mL] and good activities were found in Lantana camara [leaf ethyl acetate extract (EAE) IC(50)=19 μg/mL], Leucas aspera (flower EAE IC(50)=12.5 μg/mL), Momordica charantia (leaf EAE IC(50)=17.5 μg/mL), Phyllanthus amarus (leaf ME IC(50)=15 μg/mL) and Piper nigrum (seed EAE IC(50)=12.5 μg/mL). The leaf ME of Aegle marmelos which showed the highest activity against Plasmodium falciparum elicited low cytotoxicity (therapeutic index>13). CONCLUSION These results provide validation for the traditional usage of some medicinal plants against malaria in Dharmapuri region, Tamil Nadu, India.

Evaluation of antibacterial activity of selected medicinal plant extracts from south India against human pathogens

Abstract Objective The present study was to evaluate the antibacterial properties of 21 crude extracts from leaf and flower of Aristolochia indica (A. indica), Cassia angustifolia (C. angustifolia) , leaf of Catharanthus roseus (C. roseus), Diospyros melanoxylon (D. melanoxylon), Dolichos biflorus (D. biflorus), Gymnema sylvestre (G. sylvestre ) and Justicia procumbens (J. procumbens). Methods The ethyl acetate, acetone and methanol extract of medicinal plants were evaluated against Gram-positive Bacillus cereus (B. cereus) and Gram-negative bacteria Aeromonas hydrophila (A. hydrophila), Enterobacter aerogenes (E. aerogenes), Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) by using well diffusion assay and minimum inhibitory concentration (MIC). Results The crude plant extracts demonstrated broad spectrum activity against all bacteria. The highest inhibitory zone was observed in leaf methanol extract of A. indica against E. aerogenes (25 mm), and E. coli (20 mm), flower methanol extract of C. angustifolia against B. cereus (22 mm) and leaf acetone extract of G. sylvestre against B. cereus (22mm). The MIC values of leaf methanol extract of A. indica against K. pneumonia (22.6μg/ml), and flower extract showed against E. coli (MIC: 24.2μg/ml), leaf ethyl acetate extract of C. angustifolia against K. pneumoniae (MIC: 28.4μg/ml). Acetone ethyl acetate and methanol extracts of D. melanoxylon and D. biflorus showed the lowest MIC activity value of >30 μg/ml against all tested pathogens. Conclusion The antibacterial activity could be confirmed in most species used in traditional medicine in South India. Nevertheless, traditional knowledge might provide some leads to elucidate potential candidates for future development of new antibiotic agents.

Effect of sub-acute exposure to nickel nanoparticles on oxidative stress and histopathological changes in Mozambique tilapia, Oreochromis mossambicus

The aim of the present study was to assess the oxidative stress, antioxidant response and histopathological changes of nickel nanoparticles (Ni NPs) exposure (14 days) in Mozambique tilapia, Oreochromis mossambicus. Ni NPs were synthesized by metal salt reduction method and characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The XRD peaks at 44°, 51° and 76° were indexed to the (111), (200) and (220) Braggs reflections of cubic structure of Nickel, respectively. The crystallite sizes were calculated using Scherrers formula applied to the major intense peaks and found to be the size of 56nm. TEM images showed that the synthesized Ni NPs are spherical in shape. Biochemical analysis indicated that the superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity was significantly affected by Ni NPs treated O. mossambicus. Reduced antioxidant enzymes and the contents of antioxidants were lowered in the liver and gills of fishes treated with Ni NPs. After 14 days of exposure, a significant accumulation of Ni in the Ni NPs in experimental group was observed in the gill and skin tissues, with the highest levels found in the liver. Ni NPs exposed fish showed nuclear hypertrophy (NH), nuclear degeneration (ND), necrosis (NC) and irregular-shaped nuclei were observed in liver tissue. The hyperplasia of the gill epithelium (GE), lamellar fusion of secondary lamellae (LF), dilated marginal channel (MC), epithelial lifting (EL) and epithelial rupture were observed in gill tissue. Degeneration in muscle bundles (DM), focal area of necrosis (NC) vacuolar degeneration in muscle bundles (VD), edema between muscle bundles (ED) and splitting of muscle fibers were noticed in skin tissue. Further ecotoxicological evaluation will be made concerning the risk of Ni NPs on aquatic environment.

Novel and simple approach using synthesized nickel nanoparticles to control blood-sucking parasites.

The present study was on assessment of the anti-parasitic activities of nickel nanoparticles (Ni NPs) against the larvae of cattle ticks Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum (a.) anatolicum (Acari: Ixodidae), fourth instar larvae of Anopheles subpictus, Culex quinquefasciatus and Culex gelidus (Diptera: Culicidae). The metallic Ni NPs were synthesized by polyol process from Ni-hydrazine as precursor and Tween 80 as both the medium and the stabilizing reagent. The synthesized Ni NPs were characterized by Fourier transform infrared (FTIR) spectroscopy analysis which indicated the presence of Ni NPs. Synthesized Ni NPs showed the X-ray diffraction (XRD) peaks at 42.76°, 53.40°, and 76.44°, identified as 111, 220, and 200 reflections, respectively. Scanning electron microscopy (SEM) analysis of the synthesized Ni NPs clearly showed that the Ni NPs were spherical in shape with an average size of 150 nm. The Ni NPs showed maximum activity against the larvae of R. (B.) microplus, H. a. anatolicum, A. subpictus, C. quinquefasciatus and C. gelidus with LC(50) values of 10.17, 10.81, 4.93, 5.56 and 4.94 mg/L; r(2) values of 0.990, 0.993, 0.992, 0.950 and 0.988 and the efficacy of Ni-hydrazine complexes showed the LC(50) values of 20.35, 22.72, 8.29, 9.69 and 7.83 mg/L; r(2) values of 0.988, 0.986, 0.989, 0.944 and 0.978, respectively. The findings revealed that synthesized Ni NPs possess excellent larvicidal parasitic activity. To the best of our knowledge, this is the first report on larvicidal activity of blood feeding parasites using synthesized Ni NPs.

An Investigation of the Cytotoxicity and Caspase-Mediated Apoptotic Effect of Green Synthesized Zinc Oxide Nanoparticles Using Eclipta prostrata on Human Liver Carcinoma Cells

Cancer is a leading cause of death worldwide and sustained focus is on the discovery and development of newer and better tolerated anticancer drugs, especially from plants. In the present study, a simple, eco-friendly, and inexpensive approach was followed for the synthesis of zinc oxide nanoparticles (ZnO NPs) using the aqueous leaf extract of Eclipta prostrata. The synthesized ZnO NPs were characterized by UV-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), High-resolution transmission electron microscopy (HRTEM), and Selected area (electron) diffraction (SAED). The HRTEM images confirmed the presence of triangle, radial, hexagonal, rod, and rectangle, shaped with an average size of 29 ± 1.3 nm. The functional groups for synthesized ZnO NPs were 3852 cm−1 for H-H weak peak, 3138 cm−1 for aromatic C-H extend, and 1648 cm−1 for Aromatic ring stretch. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT), caspase and DNA fragmentation assays were carried out using various concentrations of ZnO NPs ranging from 1 to 100 mg/mL. The synthesized ZnO NPs showed dose dependent cytopathic effects in the Hep-G2 cell line. At 100 mg/mL concentration, the synthesized ZnO NPs exhibited significant cytotoxic effects and the apoptotic features were confirmed through caspase-3 activation and DNA fragmentation assays.

Green synthesis of copper nanoparticles using Eclipta prostrata leaves extract and their antioxidant and cytotoxic activities

The present study outlines the development of a method to synthesize copper nanoparticles (CuNPs) by mixing copper acetate solution with leaf extract of Eclipta prostrata without using any surfactant or external energy. E. prostrata leaf extract function as an excellent reducing agent of copper ions, and the biosynthesized CuNPs are safer for the environment. The powder X-ray diffraction (XRD) pattern provided evidence for the formation of face-centered cubic structure ranging from 23 to 57 nm, with an average size of 31±1.2 nm. Fourier transform infrared spectroscopy (FTIR) was used to identify the biomolecules and capping reagents in the E. prostrata leaf extract that may be responsible for the reduction of copper ions and the stability of the bioreduced nanoparticles. The biosynthesized CuNPs displayed considerable antioxidant capacity. Similarly, in vitro anticancer studies demonstrated the cytotoxicity value of synthesized CuNPs against tested HepG2 cells. The findings of the present study suggested that biosynthesized CuNPs that utilize extracts of E. prostrata may be used for therapeutic application, and thus are a promising nanomaterial.