Abdul Abdul Rahuman

Larvicidal activity of synthesized silver nanoparticles using Eclipta prostrata leaf extract against filariasis and malaria vectors.

Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In this study, larvicidal activity of synthesized silver nanoparticles (AgNPs) utilizing aqueous extract from Eclipta prostrata, a member of the Asteraceae was investigated against fourth instar larvae of filariasis vector, Culex quinquefasciatus say and malaria vector, Anopheles subpictus Grassi (Diptera: Culicidae). The synthesized AgNPs characterized by UV-vis spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). SEM analyses of the synthesized AgNPs were clearly distinguishable measured 35-60 nm in size. Larvae were exposed to varying concentrations of aqueous extract of synthesized AgNPs for 24h. The maximum efficacy was observed in crude aqueous, and synthesized AgNPs against C. quinquefasciatus (LC(50)=27.49 and 4.56 mg/L; LC(90)=70.38 and 13.14 mg/L), and against A. subpictus (LC(50)=27.85 and 5.14 mg/L; LC(90)=71.45 and 25.68 mg/L) respectively. The chi-square value were significant at p<0.05 level. These results suggest that the synthesized AgNPs have the potential to be used as an ideal eco-friendly approach for the control of the Culex tritaeniorhynchus and A. subpictus. This method is considered as a new approach to control vectors. Therefore, this study provides first report on the mosquito larvicidal activity of synthesized AgNPs against vectors.

Novel microbial route to synthesize ZnO nanoparticles using Aeromonas hydrophila and their activity against pathogenic bacteria and fungi

In the present work, we describe a low-cost, unreported and simple procedure for biosynthesis of zinc oxide nanoparticles (ZnO NPs) using reproducible bacteria, Aeromonas hydrophila as eco-friendly reducing and capping agent. UV-vis spectroscopy, XRD, FTIR, AFM, NC-AFM and FESEM with EDX analyses were performed to ascertain the formation and characterization of ZnO NPs. The synthesized ZnO NPs were characterized by a peak at 374 nm in the UV-vis spectrum. XRD confirmed the crystalline nature of the nanoparticles and AFM showed the morphology of the nanoparticle to be spherical, oval with an average size of 57.72 nm. Synthesized ZnO NPs showed the XRD peaks at 31.75°, 34.37°, 47.60°, 56.52°, 66.02° and 75.16° were identified as (100), (002), (101), (102), (110), (112) and (202) reflections, respectively. Rietveld analysis to the X-ray data indicated that ZnO NPs have hexagonal unit cell at crystalline level. The size and topological structure of the ZnO NPs was measured by NC-AFM. The morphological characterization of synthesized nanoparticles was analyzed by FESEM and chemical composition by EDX. The antibacterial and antifungal activity was ended with corresponding well diffusion and minimum inhibitory concentration. The maximum zone of inhibition was observed in the ZnO NPs (25 μg/mL) against Pseudomonas aeruginosa (22±1.8 mm) and Aspergillus flavus (19±1.0 mm). Bacteria-mediated ZnO NPs were synthesized and proved to be a good novel antimicrobial material for the first time in this study.

Effect of Feronia limonia on mosquito larvae

Bioassay guided fractionation of the acetone extract of Feronia limonia dried leaves afforded a potent mosquito larvicide, identified as n-hexadecanoic acid and found to be effective against fourth instar larvae of Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti, with LC50 of 129.24, 79.58 and 57.23 ppm, respectively.

Fungus-mediated biosynthesis and characterization of TiO2 nanoparticles and their activity against pathogenic bacteria

In the present study, the biosynthesis of TiO(2) nanoparticles (TiO(2) NPs) was achieved by a novel, biodegradable and convenient procedure using Aspergillus flavus as a reducing and capping agent. Research on new, simple, rapid, eco-friendly and cheaper methods has been initiated. TiO(2) NPs were characterized by FTIR, XRD, AFM, SEM and TEM studies. The X-ray diffraction showed the presence of increased amount of TiO(2) NPs which can state by the presence of peaks at rutile peaks at 100, 002, 100 and anatase forms at 101 respectively. SEM observations revealed that synthesized TiO(2) NPs were spherical, oval in shape; individual nanoparticles as well as a few aggregate having the size of 62-74 nm. AFM shows crystallization temperature was seen on the roughness of the surface of TiO(2). The Minimum inhibitory concentration value for the synthesized TiO(2) NPs was found to be 40 μg ml(-1) for Escherichia coli, which was corresponding to the value of well diffusion test. This is the first report on antimicrobial activity of fungus-mediated synthesized TiO(2) NPs, which was proved to be a good novel antibacterial material.

Efficient phyto-synthesis and structural characterization of rutile TiO2 nanoparticles using Annona squamosa peel extract.

In the present study, the biosynthesis of rutile TiO(2) nanoparticles (TiO(2) NPs) was achieved by a novel, biodegradable and convenient procedure using fruit peel Annona squamosa aqueous extract. This is the first report on the new, simple, rapid, eco-friendly and cheaper methods for the synthesis of rutile TiO(2) NPs at lower temperature using agricultural waste. Rutile TiO(2) NPs were characterized by UV, XRD, SEM, TEM and EDS studies. The UV-Vis spectrophotometer results were promising and showed a rapid production of TiO(2) NPs with a surface plasmon resonance occurring at 284 nm. The formation of the TiO(2) NPs as observed from the XRD spectrum is confirmed to be TiO(2) particles in the rutile form as evidenced by the peaks at 2θ=27.42°, 36.10°, 41.30° and 54.33° when compared with the literature. The TEM images showed polydisperse nanoparticles with spherical shapes and size 23±2 nm ranges.

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.

Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus and Culex gelidus.

OBJECTIVE To investigate the larvicidal activity of synthesized silver nanoparticles (Ag NPs) utilizing aqueous bark extract of Ficus racemosa (F. racemosa) was tested against fourth instar larvae of filariasis vector, Culex quinquefasciatus (Cx. quinquefasciatus) and japanese encephalitis vectors, Culex gelidus (Cx. gelidus). METHODS The synthesized Ag NPs was characterized by UV-vis spectrum, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). The larvicidal activities were assessed for 24 h against the larvae of Cx. quinquefasciatus and Cx. gelidus with varying concentrations of aqueous bark extract of F. racemosa and synthesized Ag NPs. LC(50) and r(2) values were calculated. RESULTS The maximum efficacy was observed in crude aqueous extract of F. racemosa against the larvae of Cx. quinquefasciatus and Cx. gelidus (LC(50)=67.72 and 63.70 mg/L; r(2)=0.995 and 0.985) and the synthesized Ag NPs (LC(50)=12.00 and 11.21 mg/L; r(2)=0.997 and 0.990), respectively. Synthesized Ag NPs showed the XRD peaks at 2 θ values of 27.61, 29.60, 35.48, 43.48 and 79.68 were identified as (210), (121), (220), (200) and (311) reflections, respectively. The FTIR spectra of Ag NPs exhibited prominent peaks at 3,425, 2,878, 1,627 and 1,382 in the region 500-3,000 cm(-1). The peaks correspond to the presence of a stretching vibration of (NH) C=O group. SEM analysis showed shape in cylindrical, uniform and rod with the average size of 250.60 nm. CONCLUSIONS The biosynthesis of silver nanoparticles using bark aqueous extract of F. racemosa and its larvicidal activity against the larvae of disease spreading vectors. The maximum larvicidal efficacy was observed in the synthesized Ag NPs.

Evaluation of different extracts and synthesised silver nanoparticles from leaves of Euphorbia prostrata against Haemaphysalis bispinosa and Hippobosca maculata

The present study was based on assessments of the antiparasitic activity to determine the efficacies of hexane, chloroform, ethyl acetate, acetone, methanol and aqueous leaf extracts of Euphorbia prostrata Ait. (Euphorbiaceae) and synthesised Ag nanoparticles (NPs) using aqueous leaf extract against the adult cattle tick Haemaphysalis bispinosa Neumann (Acarina: Ixodidae) and the haematophagous fly Hippobosca maculata Leach (Diptera: Hippoboscidae). Synthesised Ag NPs were characterised with ultraviolet-vis (UV-vis) spectrum, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) support the biosynthesis of Ag NPs. Parasites were exposed to varying concentrations of plant extracts and synthesised silver NPs for 24 h. All extracts showed the maximum toxic effect on parasites; however, the highest mortality was found in the hexane, chloroform, ethyl acetate, acetone, methanol and aqueous leaf extracts of E. prostrata and synthesised Ag NPs against the adult of H. bispinosa (LC(50)=45.24, 40.07, 21.91, 25.32, 19.30, 10.16 and 2.30 ppm; LC(90)=86.95, 88.66, 70.92, 83.22, 48.28, 70.27 and 8.28 ppm) and against H. maculata (LC(50)=39.37, 41.98, 19.92, 27. 93, 21.97, 9.79 and 2.55 ppm; LC(90)=89.44, 98.52, 76.59, 90.18, 55.07, 54.35 and 9.03 ppm), respectively. Mortality of 100% was found in synthesised Ag NPs at a concentration of 10 mg l(-1). UV-vis spectrograph of the colloidal solution of Ag NPs has been recorded as a function of time. The absorption spectrum of E. prostrata leaf extracts at different wavelengths ranging from 300 to 600 nm revealed a peak at 420 nm after 6 h. The FTIR spectra of Ag NPs exhibited prominent peaks at 3431; 1616; 1381; 1045; 818; 509; and 420 cm(-1). SEM analyses of the synthesised Ag NPs were rod shaped and measured 25-80 nm with an average size of 52.4 nm. The chemical composition of aqueous leaf extract was analysed by gas chromatography-mass spectrometry (GC-MS). The major chemical constituent was identified as 2-phenylethanol. These results suggest that the leaf methanol, aqueous extracts of E. prostrata and green synthesis of Ag NPs have the potential to be used as an ideal eco-friendly approach for the control of H. bispinosa and H. maculata. In addition, toxicity tests were conducted to analyse the toxicological effects of particle size on Daphnia magna and Ceriodaphnia dubia, and the animal model test was evaluated against Bos indicus for 24-h treatment. No toxicity on daphnids and no adverse effects were noted on animals after exposure to solvent extracts and synthesised Ag NPs.

Adulticidal and larvicidal efficacy of some medicinal plant extracts against tick, fluke and mosquitoes

The adulticidal and larvicidal effect of indigenous plant extracts were investigated against the adult cattle tick Haemaphysalis bispinosa Neumann, 1897 (Acarina: Ixodidae), sheep fluke Paramphistomum cervi Zeder, 1790 (Digenea: Paramphistomatidae), fourth instar larvae of malaria vector, Anopheles subpictus Grassi and Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae). The aim of this study was to evaluate the toxic effect of leaf hexane, chloroform, ethyl acetate, acetone and methanol extracts of Annona squamosa L., Centella asiatica (L.) Urban, Gloriosa superba L., Mukia maderaspatensis (L.) M.Roem, Pergularia daemia (Forsk.) Chiov. and Phyllanthus emblica L. were exposed to different concentrations. All plant extracts showed moderate toxic effect on parasites after 24h of exposure; however, the highest mortality was found in leaf hexane extract of A. squamosa, methanol extracts of G. superba and P. emblica against H. bispinosa (LC(50)=145.39, 225.57 and 256.08ppm); methanol extracts of C. asiatica, G. superba, P. daemia and P. emblica against P. cervi (LC(50)=77.61, 60.16, 59.61, and 60.60ppm); acetone, ethyl acetate extracts of A. squamosa, methanol extract of C. asiatica, acetone extracts of G. superba, ethyl acetate, hexane and methanol extracts of P. daemia against A. subpictus (LC(50)=17.48, 18.60, 26.62, 18.43, 34.06, 13.63, and 50.39ppm); and chloroform, ethyl acetate extracts of A. squamosa, ethyl acetate extract of P. daemia, ethyl acetate and methanol extracts of P. emblica against C. tritaeniorhynchus (LC(50)=63.81, 60.01, 31.94, 69.09, and 54.82ppm), respectively. These results demonstrate that methanol extracts of C. asiatica, G. superba, P. daemia and P. emblica extracts may serve as parasites control even in their crude form.

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).