Manickam Paulpandi

In vivo and in vitro effectiveness of Azadirachta indica-synthesized silver nanocrystals against Plasmodium berghei and Plasmodium falciparum, and their potential against malaria mosquitoes

Malaria transmission is a serious emergence in urban and semiurban areas worldwide, becoming a major international public health concern. Malaria is transmitted through the bites of Anopheles mosquitoes. The extensive employ of synthetic pesticides leads to negative effects on human health and the environment. Recently, plant-synthesized nanoparticles have been proposed as highly effective mosquitocides. In this research, we synthesized silver nanoparticles (AgNP) using the Azadirachta indica seed kernel extract as reducing and stabilizing agent. AgNP were characterized by UV-vis spectrophotometry, SEM, EDX, XRD and FTIR spectroscopy. The A. indica seed kernel extract was toxic against Anopheles stephensi larvae and pupae, LC50 were 232.8ppm (larva I), 260.6ppm (II), 290.3ppm (III), 323.4ppm (IV), and 348.4ppm (pupa). AgNP LC50 were 3.9ppm (I), 4.9ppm (II), 5.6ppm (III), 6.5ppm (IV), and 8.2ppm (pupa). The antiplasmodial activity of A. indica seed kernel extract and AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of A. indica seed kernel extract were 63.18μg/ml (CQ-s) and 69.24μg/ml (CQ-r). A. indica seed kernel-synthesized AgNP achieved IC50, of 82.41μg/ml (CQ-s) and 86.12μg/ml (CQ-r). However, in vivo anti-plasmodial experiments conducted on Plasmodium berghei infecting albino mice showed moderate activity of the A. indica extract and AgNP. Overall, this study showed that the A. indica-mediated fabrication of AgNP is of interest for a wide array of purposes, ranging from IPM of mosquito vectors to the development of novel and cheap antimalarial drugs.

Fabrication of nano-mosquitocides using chitosan from crab shells: Impact on non-target organisms in the aquatic environment

Mosquitoes are arthropods of huge medical and veterinary relevance, since they vector pathogens and parasites of public health importance, including malaria, dengue and Zika virus. Currently, nanotechnology is considered a potential eco-friendly approach in mosquito control research. We proposed a novel method of biofabrication of silver nanoparticles (AgNP) using chitosan (Ch) from crab shells. Ch-AgNP nanocomposite was characterized by UV-vis spectroscopy, FTIR, SEM, EDX and XRD. Ch-AgNP were tested against larvae and pupae of the malaria vector Anopheles stephensi obtaining LC50 ranging from 3.18 ppm (I) to 6.54 ppm (pupae). The antibacterial properties of Ch-AgNP were proved against Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi, while no growth inhibition was reported in assays conducted on Proteus vulgaris. Concerning non-target effects, in standard laboratory considtions the predation efficiency of Danio rerio zebrafishes was 68.8% and 61.6% against I and II instar larvae of A. stephensi, respectively. In a Ch-AgNP-contaminated environment, fish predation was boosted to 89.5% and 77.3%, respectively. Quantitative analysis of antioxidant enzymes SOD, CAT and LPO from hepatopancreas of fresh water crabs Paratelphusa hydrodromous exposed for 16 days to a Ch-AgNP-contaminated aquatic environment were conducted. Notably, deleterious effects of Ch-AgNP contaminating aquatic enviroment on the non-target crab P. hydrodromous were observed, particularly when doses higher than 8-10ppm are tested. Overall, this research highlights the potential of Ch-AGNP for the development of newer control tools against young instar populations of malaria mosquitoes, also highlighting some risks concerned the employ of nanoparticles in aquatic environments.

Theranostic potentials of multifunctional chitosan–silver–phycoerythrin nanocomposites against triple negative breast cancer cells

Cancer nanotheranostic materials are useful in real-time monitoring of drug delivery and therapeutic action against tumor cells as they co-deliver therapeutic and imaging functions. In this study, we report the use of natural fluorescent protein (R-phycoerythrin (PE)) in the preparation of novel multifunctional chitosan–silver–phycoerythrin nanocomposites (CS–Ag–PE NCs) and the theranostic potentials of the synthesized nanocomposites (NCs) were evaluated against triple negative breast cancer (MDA-MB-231) cells. Absorption behavior of the synthesized CS–Ag NCs and CS–Ag–PE NCs at different pH was studied by UV-Vis and FT-IR spectroscopy for determining the interaction of silver with chitosan and CS–Ag NCs with PE. Morphological features of CS–Ag NCs and CS–Ag–PE NCs and cellular uptake of CS–Ag–PE NCs were evaluated by TEM. Flow cytometry analyses were performed to determine the conjugation efficiency of CS–Ag-NCs to PE, stability of the CS–Ag–PE NCs and cellular localization of NCs at dose-dependent concentrations. Further, we substantiated the effect of CS–Ag–PE NCs in the activation of ROS mediated caspase-dependent intrinsic apoptosis by analyzing the expression of apoptotic proteins and bcl-2 family genes, respectively. The ionic interaction between PE and CS–Ag NCs resulted in a stable theranostic fluorescent NC complex that enabled the real time probing of delivery, distribution and therapeutic functions of NCs in cancer cells. The theranostic NCs of this study exhibited apoptotic induction potential in cancer cells but low toxicity in normal breast cells.

In vitro anti-viral effect of β-santalol against influenza viral replication.

The anti-influenza A/HK (H3N2) virus activity of β-santalol was evaluated in MDCK cells and investigated the effect of β-santalol on synthesis of viral mRNAs. β-Santalol was investigated for its antiviral activity against influenza A/HK (H3N2) virus using a cytopathic effect (CPE) reduction method. β-Santalol exhibited anti-influenza A/HK (H3N2) virus activity of 86% with no cytotoxicity at the concentration of 100 μg/ml reducing the formation of a visible CPE. Oseltamivir also showed moderate antiviral activity of about 83% against influenza A/HK (H3N2) virus at the concentration of 100 μg/ml. Furthermore, the mechanism of anti-influenza virus action in the inhibition of viral mRNA synthesis was analyzed by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR), and the data indicated an inhibitory effect in late viral RNA synthesis compared with oseltamivir in the presence of 100 μg/ml of β-santalol. β-Santalol should be further studied for therapeutic and prophylactic potential especially for influenza epidemics and pandemics.

Genetic deviation in geographically close populations of the dengue vector Aedes aegypti (Diptera: Culicidae): influence of environmental barriers in South India

Mosquitoes are vectors of devastating pathogens and parasites, causing millions of deaths every year. Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. Recently, dengue transmission has strongly increased in urban and semiurban areas, becoming a major international public health concern. Aedes aegypti (Diptera: Culicidae) is a primary vector of dengue. Shedding light on genetic deviation in A. aegypti populations is of crucial importance to fully understand their molecular ecology and evolution. In this research, haplotype and genetic analyses were conducted using individuals of A. aegypti from 31 localities in the north, southeast, northeast and central regions of Tamil Nadu (South India). The mitochondrial DNA region of cytochrome c oxidase 1 (CO1) gene was used as marker for the analyses. Thirty-one haplotypes sequences were submitted to GenBank and authenticated. The complete haplotype set included 64 haplotypes from various geographical regions clustered into three groups (lineages) separated by three fixed mutational steps, suggesting that the South Indian Ae. aegypti populations were pooled and are linked with West Africa, Columbian and Southeast Asian lineages. The genetic and haplotype diversity was low, indicating reduced gene flow among close populations of the vector, due to geographical barriers such as water bodies. Lastly, the negative values for neutrality tests indicated a bottle-neck effect and supported for low frequency of polymorphism among the haplotypes. Overall, our results add basic knowledge to molecular ecology of the dengue vector A. aegypti, providing the first evidence for multiple introductions of Ae. aegypti populations from Columbia and West Africa in South India.

An in vitro analysis of H1N1 viral inhibition using polymer coated superparamagnetic Fe3O4 nanoparticles

Monodispersed Fe3O4 nanoparticles were prepared by a polyol assisted solvothermal method and their activity against H1N1 influenza A virus was studied. The present study also elucidates the influence of size, shape and surface properties of the pristine, as well as polymer coated, magnetite nanoparticles. X-ray diffraction and Fourier transform infrared spectroscopic observations confirm the high crystallinity and the polymer attachment with the magnetite nanoparticles. Transmission electron microscopy (TEM) images confirm the monodispersed nanoprisms and flower like morphologies of the magnetite nanoparticles. The superparamagnetic behavior and other magnetic properties were also studied by measuring the hysteresis loop using a vibrating sample magnetometer. The cell viability studies of the magnetite nanoparticles using a standard MTT assay confirm the non-toxic nature of the samples. Reverse transcription polymerase chain reaction (RT-PCR) analysis confirms the Fe3O4 nanoparticles inhibit influenza viral RNA synthesis in MDCK cells.

Protein regulation and Apoptotic induction in human breast carcinoma cells (MCF-7) through lectin from G. beauts.

Lectins are proteins that show a variety of biological activities. Nevertheless, information on lectin from Gluttonous beauts and their anticancer activities are very limited. In this study, we purified a lectin from hemolymph of G. beauts and identified its molecular weight to be 66kDa. The effect of lectin at different concentrations (μg/mL) on the cell growth and apoptosis were evaluated against MCF-7 and MCF-10A cells, whereas cytotoxicity to the MCF-7 cells mediated by lectin was observed and the mechanism of action of the lectin in including apoptosis in cancer cells via the intrinsic pathway was also proposed. The MCF-7 cells were employed for in vitro studies on cytotoxicity, induction of apoptosis and apoptotic DNA fragmentation. In MCF-10A cells lectin did not show any adverse effect even at higher concentration. Cell cycle analysis also showed a significant cell cycle arrest on selected cells after lectin treatment. Western blotting suggested that lectin up regulates the apoptotic protein expression in MCF-7 cells while it down regulates the level of Bcl-2 expression.

Probing the interaction of thionine with human serum albumin by multispectroscopic studies and its in vitro cytotoxic activity toward MCF-7 breast cancer cells

The studies on protein–dye interactions are important in biological process and it is regarded as vital step in rational drug design. The interaction of thionine (TH) with human serum albumin (HSA) was analyzed using isothermal titration calorimetry (ITC), spectroscopic, and molecular docking technique. The emission spectral titration of HSA with TH revealed the formation of HSA–TH complex via static quenching process. The results obtained from absorption, synchronous emission, circular dichroism, and three-dimensional (3D) emission spectral studies demonstrated that TH induces changes in the microenvironment and secondary structure of HSA. Results from ITC experiments suggested that the binding of TH dye was favored by negative enthalpy and a favorable entropy contribution. Site marker competitive binding experiments revealed that the binding site of TH was located in subdomain IIA (Sudlow site I) of HSA. Molecular docking study further substantiates that TH binds to the hydrophobic cavity of subdomain IIA (Sudlow site I) of HSA. Further, we have studied the cytotoxic activity of TH and TH–HSA complex on breast cancer cell lines (MCF-7) by MTT assay and LDH assay. These studies revealed that TH–HSA complex showed the higher level of cytotoxicity in cancer cells than TH dye-treated MCF-7 cells and the significant adverse effect did not found in the normal HBL-100 cells. Fluorescence microscopy analyses of nuclear fragmentation studies validate the significant reduction of viability of TH–HSA-treated human MCF-7 breast cancer cells through activation of apoptotic-mediated pathways. Graphical abstract

Induction of intrinsic apoptotic pathway and cell cycle arrest via baicalein loaded iron oxide nanoparticles as a competent nano-mediated system for triple negative breast cancer therapy

Magnetic nanoparticles have shown an increasing number of applications in the field of molecular medicine. In the present study we investigated the controlled synthesis of biocompatible polymer coated iron oxide nanoparticles (Fe2O3) loaded with baicalein and evaluated these for their drug loading and release behaviour. Moreover, the loaded particles were evaluated for their anti-proliferation, cell cycle arrest and apoptosis activation properties in triple negative breast cancer cells. The structure, morphology and magnetic properties of the prepared materials were studied by using scanning electronic microscopy, transmission electronic microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetric analysis, dynamic light scattering analysis and zeta potential analysis. DLS and TEM analysis confirms that the size of the synthesized iron oxide nanoparticles are about 90–100 nm and that they are extremely crystalline and spherical in nature. FTIR analysis confirms that the baicalein molecules were conjugated with PEG-coated iron oxide nanoparticles. X-ray diffraction patterns indicate that the magnetic nanoparticles were highly pure with a spinel structure. Baicalein loaded nanoparticles show a controlled release profile in response to various pH levels. We found significant cell cycle arrest at various phases in the treated group and subsequent apoptotic cell death to be evidenced by AO/EtBr, DAPI and PI of fluorescence microscopy analysis. The TUNEL assay evidences that DNA damage occurs in the treated cells. Further baicalein loaded iron oxide nanoparticles exhibit significant down-regulation of the anti-apoptotic protein Bcl-2 and up-regulation of pro-apoptotic proteins evidenced by Western blotting. Our findings clearly demonstrate that baicalein loaded iron oxide nanoparticles could efficiently deliver the drug of interest, and initiate and execute the apoptotic process in triple negative breast cancer cells. This could open a new window in polymer surface chemistry to develop metal oxide based drug delivery systems for all kinds of cancer therapeutics.