Devarajan Natarajan

Spectral and HRTEM analyses of Annona muricata leaf extract mediated silver nanoparticles and its Larvicidal efficacy against three mosquito vectors Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

Mosquitoes transmit various diseases which mainly affect the human beings and every year cause millions of deaths globally. Currently available chemical and synthetic mosquitocidal agents pose severe side effects, pollute the environment vigorously, and become resistance. There is an urgent need to identify and develop the cost effective, compatible and eco-friendly product for mosquito control. The present study was aimed to find out the larvicidal potential of aqueous crude extract and green synthesized silver nanoparticles (AgNPs) from Annona muricata leaves were tested against fourth instar larvae of three important mosquitoes i.e. Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti using different concentrations of AgNPs (10, 20, 30, 40 and 50 ppm) and the aqueous leaf extract (100, 200, 300, 400, and 500 ppm) for 24 and 48 h. The maximum mortality was noticed in AgNPs than aqueous leaf extract of A. muricata against tested mosquitoes with least LC50 values of 37.70, 31.29, and 20.65 ppm (24h) and 546.7, 516.2, and 618.4 ppm (48 h), respectively. All tested concentrations of AgNps exhibited 100% mortality in A. aegypti larvae at 48 hour observation. In addition, the plant mediated AgNPs were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy, particle size analyser, X-ray diffraction, high resonance transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis for confirmation of nanoparticle synthesis. Based on the findings of the study suggests that the use of A. muricata plant mediated AgNPs can act as an alternate insecticidal agents for controlling target mosquitoes.

Mycosynthesis of silver nanoparticles from Beauveria bassiana and its larvicidal, antibacterial, and cytotoxic effect on human cervical cancer (HeLa) cells

Mosquitoes are the primary vector for transmitting endemic diseases such as yellow fever, Chikungunya, dengue and dengue hemorrhagic fever, malaria, Japanese encephalitis, and lymphatic filariasis in humans and animals. The present study was carried out by the myco-synthesis of silver nanoparticles (AgNPs) using entomopathogenic fungi Beauveria bassiana and its mosquitocidal properties against different larval instars of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The synthesized AgNPs were characterized by UV-visible spectroscopy, X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), Particle Size Analyzer (PSA), Transmission Electron Microscope (TEM), and Energy Dispersive X-ray spectroscopy (EDX), respectively. The surface plasmon resonance band was observed at 430 ± 1.5 nm in the UV-spectrum. The XRD spectrum of crystallic AgNPs shows four strong intense peaks at 2θ values of 38.12°, 54.14°, 64.18°, and 77.48° assigned to 111, 200, 220, and 311, respectively. The complex nature of AgNPs was confirmed by an FTIR spectrum with peaks observed at 3205.77, 1653.20, 1383.50, 1071.12, 825.58, 668.85, and 565.17 cm−1 respectively. The average size of synthesized AgNPs was confirmed by PSA (128 nm). TEM images confirmed the AgNPs size about 20.44 to 34.16 nm (spherical shape) and EDX spectral peak was observed between 1.741 to 5.430 keV. The larvicidal efficacy of different concentrations (50, 100, 150, 200, 250, and 300 μg mL−1) of mycosynthesized AgNPs was tested against first, second, third, and fourth larval instars of A. aegypti (LC50 = 34.655, 20.522, 22.621, and 22.536; LC90 = 170.207, 144.763, 120.934, and 198.394 μg mL−1), A. stephensi (LC50 = 45.822, 16.777, 22.873, and 30.787; LC90 = 298.812, 111.038, 142.154, and 193.092 μg mL−1), and C. quinquefasciatus (LC50 = 49.36, 26.946, 13.199, and 1.478; LC90 = 161.554, 134.590, 104.639, and 58.923 μg mL−1) and 100% mortality effect was observed with the AgNPs. The antibacterial property of synthesized nanoparticles was observed by the well diffusion method with multi-drug resistant bacteria such as Escherichia coli and Staphylococcus aureus. The fungal mediated silver nanoparticles are comparatively rapid and less expensive and have broad application to antibacterial therapy in modern medicine. The cytotoxic effects of silver nanoparticles showed IC50 values of 28.8 ± 2.5 μg mL−1 against normal HeLa (cervical) cells, with a 24 h incubation period. The outcome of the study suggests that the B. bassiana synthesized silver nanoparticles would be more appropriate for environmentally safer bio insecticidal agents for controlling A. stephensi and C. quinquefasciatus mosquitoes.

Photoscopic characterization of green synthesized silver nanoparticles from Trichosanthes tricuspidata and its antibacterial potential.

The present study focused on the finding of reducing agents for the formation of silver nanoparticles (AgNPs) from the plant, Trichosanthes tricuspidata. The synthesized AgNPs were characterized using UV-Visible spectroscopy, particle size analyzer (PSA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. The UV-Visible spectrum resulted a sharp peak (at 430nm) represents the strong plasmon resonance of silver. The average size distributions of AgNPs were found to be 78.49nm, through (PSA), and the silver ion with its crystalline nature was confirmed using intensity (2θ) peak value of 38.22°, 44.66°, 64.61°, and 77.49°. The SEM micrograph revealed that the synthesized AgNPs have a spherical morphology with the size ranges from 20 to 28nm. AFM showed the presence of polydispersed AgNPs with its size (20 to 60nm in height). The gas chromatography-mass spectroscopy (GC-MS) study analyzed the responsible compounds present in the methanolic extracts for the bio-reduction of AgNPs and their antibacterial effect was studied. AgNPs exhibited preponderant activity than the methanolic extracts on clinical pathogens. Thus, the synthesized AgNPs might act as an effective antibacterial agent. Further studies are required to isolate the specific compound responsible for the reduction capability and its their inhibitory mechanisms for target bacterial strains.

Mosquitocidal Effect of Glycosmis pentaphylla Leaf Extracts against Three Mosquito Species (Diptera: Culicidae)

Background The resistance status of malaria vectors to different classes of insecticides used for public health has raised concern for vector control programmes. Alternative compounds to supplement the existing tools are important to be searched to overcome the existing resistance and persistence of pesticides in vectors and the environment respectively. The mosquitocidal effects of Glycosmis pentaphylla using different solvents of acetone, methanol, chloroform and ethyl acetate extracts against three medically important mosquito vectors was conducted. Methods Glycosmis pentaphylla plant leaves were collected from Kolli Hills, India. The WHO test procedures for larval and adult bioassays were used to evaluate extracts against mosquito vectors, and the chemical composition of extracts identified using GC-MS analysis. Results The larvicidal and adulticidal activity of G. pentaphylla plant extracts clearly impacted the three species of major mosquitoes vectors. Acetone extracts had the highest larvicidal effect against An. stephensi, Cx. quinquefasciatus and Ae. aegypti with the LC50 and LC90 values of 0.0004, 138.54; 0.2669, 73.7413 and 0.0585, 303.746 mg/ml, respectively. The LC50 and LC90 adulticide values of G. pentaphylla leaf extracts in acetone, methanol, chloroform and ethyl acetate, solvents were as follows for Cx. quinquefasciatus, An. stephensi and Ae. Aegypti: 2.957, 5.458, 2.708, and 4.777, 3.449, 6.676 mg/ml respectively. The chemical composition of G. pentaphylla leaf extract has been found in 20 active compounds. Conclusions The plant leaf extracts of G. pentaphylla bioactive molecules which are effective and can be developed as an eco-friendly approach for larvicides and adulticidal mosquitoes vector control. Detailed identification and characterization of mosquitocidal effect of individual bioactive molecules ingredient may result into biodegradable effective tools for the control of mosquito vectors.

Beauveria bassiana (Clavicipitaceae): a potent fungal agent for controlling mosquito vectors of Anopheles stephensi , Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae)

Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue, chikungunya and yellow fever, which cause significant morbidity and mortality in humans and domestic animals around the world. Entomopathogenic fungal metabolites act as a mosquito control agent and are potential alternatives to chemical control because they can be innovative and more selective than chemical insecticides. The main aim of the present study was to perform experiments on the larvicidal and pupicidal effects of the entomopathogenic fungus Beauveria bassiana (isolated from infected grasshopper) against the first to fourth instar larvae of Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The larval and pupal mortality were observed after 24 h of exposure. The efficacy of an ethyl acetate mycelium extract at all the tested concentrations (50, 100, 150, 200, 250 and 300 μg mL−1) exhibited better activity against the 1st to 4th instar larvae of An. stephensi (LC50 = 42.82, 39.45, 25.72, and 32.66; LC90 = 254.67, 367.11, 182.27, and 199.20 μg mL−1), Cx. quinquefasciatus (LC50 = 72.38, 68.11, 27.06, and 35.495; LC90 = 481.68, 254.69, 129.83, and 146.24 μg mL−1) and Ae. aegypti (LC50 = 62.50, 52.89, 58.60, and 47.12; LC90 = 314.82, 236.18, 247.53, and 278.52 μg mL−1), respectively. The pupicidal activity of the fungal mycelium extracts was tested against An. stephensi, Cx. quinquefasciatus and Ae. Aegypti, where the ethyl acetate extracts had different LC50 values (LC50 = 40.66, 54.06, 44.26, and LC90 = 184.02, 225.61, and 263.02 μg mL−1). Based on Fourier transform infrared spectroscopy (FTIR) analysis and gas chromatography-mass spectrometry (GC-MS) analyses, the ethyl acetate mycelium extract contained six major chemical compounds identified as 9,12-octadecadienoic acid (ZZ)– (63.16%), n-hexadecanoic acid (21.28%), octadecanoic acid, phenyl methyl ester (10.45%), dehydroegosterol 3,5-dinitrobenzoate (1.86%), squalene (1.66%) and bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)prophyl]maleate (1.56%). The n-hexadecanoic acid standard was found to be better larvicidal against An. stephensi, Cx. quinquefasciatus, followed by Ae. aegypti. The HPLC analysis of the ethyl acetate mycelium extract was compared with that of the n-hexadecanoic acid standard and it was found to show a similar chromatographic peak (at a retention time of 3.383 and 3.378 min). The outcome of the present study identifies the bioactive compounds obtained from B. bassiana that can be used as effective and alternate larvicidal and pupicidal agents against the An. stephensi Cx. quinquefasciatus and Ae. aegypti mosquito vectors.

Medicinal Plants for Anopheles stephensi Liston Larvae Management

Abstract Plants contain several secondary metabolites which are known to be effective in controlling a variety of insects. Chemical insecticides have been used for controlling the breeding of mosquitoes. Due to the problem of insecticide resistance and undesirable effects on non target organisms, a search for alternative larvicidal sources is necessary. Plant secondary metabolites are an ideal source for larvicides. In this study, larvicidal efficacy of different solvent (hexane, chloroform, ethyl acetate, acetone and methanol) crude leaf extracts was investigated against fourth-instar larvae of Anopheles stephensi. Larval bioassay tests were carried out as per WHO protocol and mortality was recorded after 24 h exposure. High larval mortality was observed in acetone extract of Elaeagnus indica with LC50 and LC90 values of 41.18 and 96.37 ppm respectively. The chloroform extract of B. maderaspatensis also showed a high larval mortality with LC50 and LC90 values of 49.18 ppm, and 145.45 ppm respectively. The results of this study revealed that larvicidal potential of acetone extract of Elaeagnus indica and chloroform extract of Blepharis maderaspatensis further effort to characterize the bioactive compounds can be used for effective mosquito control.

Spectral characterization and antibacterial activity of an isolated compound from Memecylon edule leaves

Memecylon edule Roxb. (Melastamataceae family) is a small evergreen tree reported as having ethnobotanical and pharmacological properties. The present study was aimed to investigate the spectral characterization and antibacterial activity of isolated pure compound (3β-hydroxyurs-12-en-28-oic acid (ursolic acid)) from Memecylon edule leaves by performing bioassay guided isolation method. The structure derivation of isolated compound was done by different spectral studies like UV, FT-IR, LC-MS, CHNS analysis, 1D (1H, 13C and DEPT-135) and 2D-NMR (HSQC and HMBC), respectively. About 99.29% purity of the compound was found in LC analysis. 1H NMR spectrum results of compound shown 48 protons appear at different shielded region and most of the protons were present in aliphatic region. Whereas, 13C NMR spectral data resulted seven methyl carbons (CH3), nine methylene carbons (CH2), seven methine carbons (CH) and six non-hydrogenated carbons (C) which are characteristic of pentacyclic triterpene. The isolated pure compound was tested for its antibacterial properties against targeted human pathogens by performing agar well diffusion, MIC and MBC assays and the result exhibits better growth inhibitory effects against S. epidermidis and S. pneumoniae, with the MIC values of 1.56 and 3.15μg/ml. The outcome of this study suggests that the bioactive compound is used for development of plant based drugs in pharmaceutical industry for combating microbial mediated diseases.

Larvicidal, Histopathological Efficacy of Penicillium daleae against Larvae of Culex quinquefasciatus and Aedes aegypti Plus Biotoxicity on Artemia nauplii a Non-target Aquatic Organism

Mosquitoes can transmit the terrible diseases to human beings. Soil-borne fungal products act as potential source for low-cost chemicals, used for developing eco-friendly control agents against mosquito-vector borne diseases. The prime aim of study was to check the larvicidal potential of fungus mycelia (by ethyl acetate solvent) extract from Penicillium daleae (KX387370) against Culex quinquefasciatus and Aedes aegypti and to test the toxicity of brine shrimp Artemia nauplii, by observing the physiological activity. The ethyl acetate extract of P. daleae mycelia (after 15 days) from Potato dextrose broth (PDB) medium revealed better result with least LC50 and LC90 values of I-IV instars larvae of Cx. quinquefasciatus (LC50 = 127.441, 129.087, 108.683, and 93.521; LC90 = 152.758, 158.169, 139.091, and 125.918 μg/ml) and Ae. aegypti (LC50 = 105.077, 83.943, 97.158, and 76.513; LC90 = 128.035, 106.869, 125.640, and 104.606 μg/ml) respectively. At higher concentration (1000 μg/ml) of extracts, mortality begins at 18 h of exposure and attained 100% mortality after 48 h exposure. Overall, the activity was depends on the dose and time of exposure to the extracts. The stereomicroscopic and histopathological analysis of Ae. aegypti and Cx. quinquefasciatus larvae treated with mycelium ethyl acetate extract showed complete disintegration of abdominal region, particularly the midgut and caeca, loss of cuticular parts and caudal hairs. Morphological characterization of the fungi was performed and taxonomically identified through 5.8s rDNA technique. The phylogenetic analysis of rDNA sequence was carried out to find out the taxonomic and the evolutionary sketch of isolate in relation to earlier described genus Penicillium. Behavior and swimming speed alteration was analyzed together with mortality. The results of the experiment indicates that swimming behavior recorder (SBR) is a appropriate tool to detect individual swimming speed of the A. nauplii organisms, since the values have been obtained in accordance with control monitored results showed the 2.75 mm s-1 and after 24 h treated found to be 0.72 mm s-1, respectively. The extract-exposed to A. nauplii showed changes in body structures, i.e., intestine enlargement, eye formation, outer shell malformations and loss of antennae. In the present study, we aimed to investigate the toxicity of the ethyl acetate extract of P. daleae on A. nauplii larvae by performing the mortality, behavior and alterations in swimming responses. This is the first time report on the larvicidal efficacy of P. daleae ethyl acetate extract against Cx. quinquefasciatus and Ae. aegypti larvae.

In vitro evaluation of antioxidant, antiproliferative potentials of bioactive extract-cum-rutin compound Isolated from Memecylon edule leaves and its molecular docking study

Abstract The current study was planned to investigate the antioxidant and anti-proliferative potential of leaf crude extracts and isolated compound (rutin) from Memecylon edule by performing the standard antioxidant and MTT assays. Results suggested that different solvents crude leaf extracts of M. edule expressed varying degree of antioxidant potential on all tested methods (DPPH, NO, OH, O2•- radicals) based on dose depended manner and they also had good reducing ability. Significant high antiradical potential was found in ethyl acetate extract (DPPH IC50 value 26.77 μg/ml, NO IC50 value 27.04 μg/ml, OH IC50 value 30.94 μg/ml, O2•- IC50 value 50.75 μg/ml and FRAP EC50 value 40.43 μg/ml) followed by other extracts. The anti-proliferative activity of potential extract (ethyl acetate extract) which possess high antioxidant activity, and isolated rutin compound was tested (by MTT assay) against U-937 and HT-60 cell lines and the results show dose dependent activity. In addition, docking studies of reported rutin compound exhibits strong inhibition on the active site of VEGFR2 than the co-crystallized ligand N,2-dimethyl-6-(7-(2-morpholinoethoxy) Quinolin-4-yloxy)benzofuran-3-carboxamide.

Anticancer potential of leaf and leaf-derived callus extracts of Aerva javanica against MCF-7 breast cancer cell line

Background: Aerva javanica is an exotic and medicinal plant in India. Aim of the Study: The main goal of this study was to evaluate the antiproliferative properties of leaf and leaf-derived callus extracts against human breast cancer cell line MCF-7. Methods: The plant parts were sequentially extracted with hexane, chloroform, ethyl acetate, acetone, and methanol. The extract was concentrated to yield the crude extract, which was tested for anticancer potentials. The anticancer potential of cytotoxic extracts was determined by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and DNA fragmentation assays in human breast cancer cell lines (MCF-7). Results: All the tested extracts showed significant antiproliferative activities in a concentration- and time-dependent manner. The inhibitory concentration of extract was tested against target cell line, and the results show in vitro leaf of A. javanica has higher inhibitory effect against the tested cancer cells at lower concentration (about 11.89 and 22.45 μg/ml) followed by other samples extracts. Conclusion: The results of the present study conclude in vitro plant sample having more potent anticancer property and support the need of further studies to isolate potential anticancer drug with cancer cell-specific cytotoxicity.