Showing papers by "Annamalai University published in 2018"

Cytochrome P450 Structure, Function and Clinical Significance: A Review

Abstract: Background The cytochrome P450 (CYP) enzymes are membrane-bound hemoproteins that play a pivotal role in the detoxification of xenobiotics, cellular metabolism and homeostasis. Induction or inhibition of CYP enzymes is a major mechanism that underlies drug-drug interactions. CYP enzymes can be transcriptionally activated by various xenobiotics and endogenous substrates through receptor-dependent mechanisms. CYP enzyme inhibition is a principal mechanism for metabolism- based drug-drug interactions. Many chemotherapeutic drugs can cause drug interactions due to their ability to either inhibit or induce the CYP enzyme system. Predictions based on in silico analyses followed by validation have identified several microRNAs that regulate CYPs. Genetic polymorphisms and epigenetic changes in CYP genes may be responsible for inter-individual and interethnic variations in disease susceptibility and the therapeutic efficacy of drugs. Objective The present review is a comprehensive compilation of cytochrome P450 structure, function, pharmacogenetics, pharmacoepigenetics and clinical significance. Conclusion Knowledge about the substrates, inducers, and inhibitors of CYP isoforms, as well as the polymorphisms of CYP enzymes may be used as an aid by clinicians to determine therapeutic strategy, and treatment doses for drugs that are metabolized by CYP gene products.

Facile green synthesis of zinc oxide nanoparticles using Ulva lactuca seaweed extract and evaluation of their photocatalytic, antibiofilm and insecticidal activity.

Abstract: The bioactivity of semiconductor nanocomplexes has been poorly studied in the field of pesticide science. In this research, the synthesis of zinc nanoparticles was accomplished through new effortless green chemistry process, using the Ulva lactuca seaweed extract as a reducing and capping agent. The production of U. lactuca-fabricated ZnO nanoparticles (Ul-ZnO Nps) was characterized by powder X-ray diffraction (XRD), UV-visible, Fourier transform infrared (FTIR) spectroscopy, selected area electron diffraction (SAED) analysis and transmission electron microscopy (TEM). The U. lactuca-fabricated ZnO NPs were tested for their photodegradative action against organic dyes, as well as for antibiofilm and larvicidal activities. The UV visible absorbance spectrum of Ul-ZnO NPs exhibited the absorbance band at 325nm and TEM highlighted average crystallite sizes of nanoparticles of 10-50nm. Methylene blue (MB) dye was efficiently corrupted under sunlight in presence of Ul-ZnO NPs. Excellent bactericidal activity was shown by the Ul-ZnO Nps on Gram positive (Bacillus licheniformis and Bacillus pumilis) and Gram negative (Escherichia coliand Proteus vulgaris) bacteria. High antibiofilm potential was noted under both dark and sunlight conditions. The impact of a single treatment with Ul-ZnO NPs on biofilm architecture was also analyzed by confocal laser scanning microscopy (CLSM) on both Gram positive and Gram negative bacteria. Moreover, Ul-ZnO NPs led to 100% mortality of Aedes aegypti fourth instar larvae at the concentration of 50μg/ml within 24h. The effects of ZnO nanoparticle-based treatment on mosquito larval morphology and histology were monitored. Overall, based on our results, we believe that the synthesis of multifunctional Ul-ZnO Nps using widely available seaweed products can be promoted as a potential eco-friendly option to chemical methods currently used for nanosynthesis of antimicrobials and insecticides.

Biopolymer gelatin-coated zinc oxide nanoparticles showed high antibacterial, antibiofilm and anti-angiogenic activity.

Abstract: The use of natural polymers in drug design plays an important role in biomedical applications. Combinations of nanoparticles (NPs) and biopolymers have been shown to be useful for many purposes. This study focused on gelatin-coated zinc oxide NPs synthesized by co-precipitation. The particles were characterized by UV–Vis spectrum, showing a main peak at 375 nm. The stability and crystalline nature of the particles was evaluated by Zeta potential and X-ray diffraction analysis. Fourier transform infrared spectroscopy (FTIR) revealed the possible functional groups of Ge-ZnO NPs, with strong bands at 3851, 3447, and 2923 cm− 1. Moreover, transmission electron microscopy (TEM) highlighted the presence of spherically shaped Ge-ZnO NPs that were 20 nm in size. Energy dispersive analysis X-ray (EDX) analysis showed that the zinc elemental content of Ge-ZnO NPs was 59.10%. The results of antibacterial activity assays revealed higher inhibition of Ge-ZnO NPs against Gram-negative Pseudomonas aeruginosa at 100 μg/ml over that against Gram-positive Enterococcus faecalis. Greater inhibition of biofilm formation was observed for Gram-negative bacteria compared to Gram-positive bacteria. In addition, Ge-ZnO NPs effectively inhibited the biofilm growth of the fungus Candida albicans at 50 μg/ml. Ge-ZnO NPs reduced the viability of hepatocarcinoma cancer cell lines at 100 μg/ml. Moreover, in chick embryos, notable anti-angiogenesis effects were observed for Ge-ZnO NPs and zinc acetate at 50 μg/ml compared to that observed testing gelatin. Overall, based on the results, Ge-ZnO NPs may be used as a novel agent for the control of biofilm-forming microbial pathogens.

Mosquito control with green nanopesticides: towards the One Health approach? A review of non-target effects

Abstract: The rapid spread of highly aggressive arboviruses, parasites, and bacteria along with the development of resistance in the pathogens and parasites, as well as in their arthropod vectors, represents a huge challenge in modern parasitology and tropical medicine. Eco-friendly vector control programs are crucial to fight, besides malaria, the spread of dengue, West Nile, chikungunya, and Zika virus, as well as other arboviruses such as St. Louis encephalitis and Japanese encephalitis. However, research efforts on the control of mosquito vectors are experiencing a serious lack of eco-friendly and highly effective pesticides, as well as the limited success of most biocontrol tools currently applied. Most importantly, a cooperative interface between the two disciplines is still lacking. To face this challenge, we have reviewed a wide number of promising results in the field of green-fabricated pesticides tested against mosquito vectors, outlining several examples of synergy with classic biological control tools. The non-target effects of green-fabricated nanopesticides, including acute toxicity, genotoxicity, and impact on behavioral traits of mosquito predators, have been critically discussed. In the final section, we have identified several key challenges at the interface between "green" nanotechnology and classic biological control, which deserve further research attention.

Microalgae as Bio-fertilizers for Rice Growth and Seed Yield Productivity

Abstract: The use of nitrogen and phosphorus in the agricultural field has led to a number of environmental problems and reduces the crop yields. Synthetic fertilizer usage is credited with increased soil erosion and degrading local ecosystem. To save the natural environment, use of organic fertilizer has become a best option and also reported as cost effective. Microalgae are considered as potential bio-fertilizers for rice cultivation as these are directly related with their nitrogen fixation ability and other positive effects for plants and soil. As a result of variability in data and N2 levels applied, significant differences between treatment and control groups were not found relative to farm. Hence, Microalgae species were recommended to be used as bio-fertilizer as an alternative to mainstream synthetic fertilizers. This is because of the increased cost of chemical fertilizer that cause soil and water pollution. In comparison, microalgae are a cheap source of N, which does not cause pollution. For this reason, the aim of the microalgae experiment as bio-fertilizer was to minimize the aggressive synthetic fertilizer use in the paddy field and to determine the potentiality of bio-fertilizer application in order to have maximum yield as well as for ensuring eco-friendly environment by avoiding chemical pollution.

Nimbolide, a neem limonoid inhibits cytoprotective autophagy to activate apoptosis via modulation of the PI3K/Akt/GSK-3β signalling pathway in oral cancer.

Abstract: Of late, nimbolide, a limonoid from the neem tree (Azadirachta indica) has gained increasing research attention owing to its potent antiproliferative and apoptosis-inducing effects. The present study was designed to investigate the effect of nimbolide on autophagy and the time point at which the phosphorylation status of GSK-3β and PI3K dictate the choice between autophagy and apoptosis in SCC131 and SCC4 oral cancer cells. Additionally, we analysed changes in the expression of proteins involved in autophagy and apoptosis after therapeutic intervention with nimbolide in a hamster model of oral oncogenesis. Furthermore, we also demonstrate changes in the expression of key genes involved in apoptosis and autophagy during the stepwise evolution of hamster and human OSCCs. Nimbolide-induced stereotypical changes in oral cancer cells characteristic of both apoptosis and autophagy. Time-course experiments revealed that nimbolide induces autophagy as an early event and then switches over to apoptosis. Nimbolide negatively regulates PI3K/Akt signalling with consequent increase in p-GSK-3βTyr216, the active form of GSK-3β that inhibits autophagy. Downregulation of HOTAIR, a competing endogenous RNA that sponges miR-126 may be a major contributor to the inactivation of PI3K/Akt/GSK3 signalling by nimbolide. Analysis of key markers of apoptosis and autophagy as well as p-AktSer473 during sequential progression of hamster and human OSCC revealed a gradual evolution to a pro-autophagic and antiapoptotic phenotype that could confer a survival advantage to tumors. In summary, the results of the present study provide insights into the molecular mechanisms by which nimbolide augments apoptosis by overcoming the shielding effects of cytoprotective autophagy through modulation of the phosphorylation status of Akt and GSK-3β as well as the ncRNAs miR-126 and HOTAIR. Development of phytochemicals such as nimbolide that target the complex interaction between proteins and ncRNAs that regulate the autophagy/apoptosis flux is of paramount importance in cancer prevention and therapeutics.

Green synthesis and characterization of biologically active nanosilver from seed extract of Gardenia jasminoides Ellis.

Abstract: This article reports the utilization of seed extract (GSE) from Gardenia jasminoides Ellis. in the synthesis of silver nanoparticles (Gs-AgNPs) with versatile biological activities. The synthesized Gs-AgNPs were spherical in shape, crystal lattice with an average size of 20 nm as confirmed by UV–vis spectrum, X-ray diffractometer (XRD), Transmission electron microscopy with Energy dispersive X-ray spectroscopy (TEM-EDS) and particle size analyses (PSA). Phenolic compounds, proteins, and terpenoids were likely involved in the Gs-AgNPs synthesis, as indicated by Fourier-transform infrared spectroscopy (FTIR) analysis. The minimum bactericidal concentration (MBC) of the Gs-AgNPs was 12.5 μg·ml−1 for S. enterica Typhimurium and 10 μg·ml−1 for S. aureus. The MBC of the Gs-AgNPs induced >70% bacterial cell death within 60 min, as confirmed by growth curve analysis followed by Confocal laser scanning microscope (CLSM). Gs-AgNPs showed the highest scavenging activity for 1, 2-diphenyl-1-picrylhydrazyl DPPH radical (92.3 ± 0.86%), Nitric oxide (NO) radical (72.5 ± 2.15%), and Hydrogen peroxide H2O2 radical (85.25 ± 1.45%). Anticancer results revealed an IC50 of 15.625 ± 1.3 μg·ml−1 for Gs-AgNPs, whereas it was 580.54 ± 2.5 μg·ml−1 for GSE. The Gs-AgNPs generated high reactive oxygen species (ROS) resulting in induced apoptosis as evident by up-regulation of apoptosis-related protein. In addition, the photocatalytic results revealed about 92% of the reduction in Coomassie Brilliant Blue dye color with Gs-AgNPs. Hence, this work provided economically viable and ecologically sustainable Gs-AgNPs as an alternative biomaterial for future therapeutic applications as antimicrobial, antioxidant, anti-cancer agents and in dye degradation for water remediation.

Attenuation of Aluminum Chloride-Induced Neuroinflammation and Caspase Activation Through the AKT/GSK-3β Pathway by Hesperidin in Wistar Rats

Abstract: Hesperidin, a flavanoglycone abundantly present in citrus fruits, is reported to have antioxidant, anti-inflammatory, and neuroprotective properties. Previous reports from our laboratory indicated the neuroprotective effect of hesperidin against aluminum chloride (AlCl3)-induced memory loss, acetylcholine esterase hyperactivity, oxidative stress, and enhanced expression of amyloid β protein biosynthesis-related markers. However, their role on AlCl3-induced inflammation, caspase activation, Tau pathology, altered Akt/GSK 3β signaling pathway, and Aβ clearance marker has not yet been fully elucidated. Intraperitonial injection of AlCl3 (100 mg/kg body weight) for 60 days significantly elevated the expressions of insulin-degrading enzyme (IDE), cyclin-dependent kinase 5 (CDK 5), and phosphoTau (pTau); inflammatory markers such as glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 (Iba-1), NF-kB, cyclooxygenase-2 (COX-2), interleukin (IL)-1β, IL-4, IL-6, tumor necrosis factor-alpha (TNF-α), inducible nitric oxide synthase (iNOS); and apoptotic markers including cytosolic cytochrome c (cyto c), caspase-3, caspase-8, and caspase-9, and lowered expressions of mitochondrial cyto c, phospho-Akt (pAkt) and phospho-glycogen synthase kinase-3β (pGSK-3β) in the hippocampus and cortex. Co-administration of hesperidin to AlCl3 rats for 60 days significantly ameliorated the aluminum-induced pathological changes. The behavioral studies also supported the above findings. Our results imply that treatment with hesperidin might be a potent option for treating the symptoms of cognitive impairment in Alzheimer’s disease by targeting its most prominent hallmarks.

Remote sensing and GIS based groundwater potential zone mapping in Ariyalur district, Tamil Nadu.

Abstract: The groundwater is the most precious resources around the world and is shrinking day by day. In connection, there is a need for demarcation of potential ground-water zone. The geographical information system (GIS) and remote sensing techniques have become important tools to locate ground-water potential zones. This research has been carried out to identify groundwater potential zone in Ariyalur of south India with help of GIS and remote sensing techniques. To identify the groundwater potential zone used by different thematic layers of geology, geomorphology, drainage, drainage density, lineaments, lineaments density, soil, rainfall, and slope with inverse distance weightage (IDW) methods. From the overall result the potential zone of groundwater in the study area classified into five classes named as very good (13.34 %), good (51.52 %), moderate (31.48 %), poor (2.82 %) and very poor (0.82 %). This study suggested that, very good potential zone of groundwater occur in patches in northern and central parts of Jayamkondam and Palur regions in Ariyalur district. The result exhibited that inverse distance weightage method offers an effective tool for interpreting groundwater potential zones for suitable development and management of groundwater resources in different hydro-geological environments.

Mangrove Forests of India

Abstract: Mangrove forests of India are globally unique with the highest record of biodiversity, gifted with the mangrove genetic paradise at Bhitarkanika, and the globally threatened wildlife species in the Sundarbans. The Sundarbans of India and Bangladesh is the only largest mangrove forest in the world colonized by the Royal Bengal Tigers. Mangroves are dense and floristically diverse along the east coast of India and the Andaman and Nicobar Islands. They are largely distributed in the high energy tidal coast of two extreme conditions: (i) humid and wet in Sundarbans with rich bio-diversity, and (ii) arid and dry in Gujarat with low biodiversity. Despite increasing pressures, the mangrove cover in India increases annually at the rate of 1.2%, as against the global mangrove cover that disappears at 0.66%. However, India has a large track of sparse mangrove stand. This article discusses the present status of mangrove forests, conservation and management strategies being followed successfully in India, and recommends the future directions for mangrove restoration, improvisation of sparse stands, participatory management, and quality publications on mangrove research.

Evaluation of antidiabetic activity of biologically synthesized silver nanoparticles using Pouteria sapota in streptozotocin-induced diabetic rats.

Abstract: Background Medicinal plants and green synthesis of silver nanoparticles (AgNPs) have proven to be good sources of agents effective in the treatment of diabetes mellitus. The present study focused on the green synthesis of AgNPs from the aqueous leaf extract of Pouteria sapota in order to evaluate the in vitro and in vivo antidiabetic properties of this extract and the synthesized AgNPs. Methods The AgNPs were biologically synthesized under ambient conditions from an aqueous leaf extract of P. sapota using the hot percolation method and were characterized using spectroscopic methods, X-ray diffraction, and scanning electron microscopy. The in vitro antidiabetic activity of the aqueous leaf extract and AgNPs was confirmed by non-enzymatic glycosylation of hemoglobin, glucose uptake by yeast cells following exposure of cells to 5 or 10 mmol/L glucose solution, and inhibition of α-amylase. Further, in vivo antidiabetic activity was assessed in streptozotocin-induced rats. Rats were treated with aqueous leaf extract (100 mg/kg) or AgNPs (10 mg/kg) for 28 days. Following treatment, rats were killed for biochemical and histopathological analysis of kidney and liver samples. Results A significant reduction in blood sugar levels was noted in rats treated with leaf extract or AgNPs. Results of in vitro and in vivo analyses in rats treated with leaf extract or AgNPs show that both the extract and the biologically synthesized AgNPs have antidiabetic activity. Conclusion The aqueous leaf extract of P. sapota and AgNPs exhibited efficient antidiabetic activity in the rat model of diabetes and therefore could have potential for development for medical applications in the future.

Cleaner emissions from a DI diesel engine fueled with waste plastic oil derived from municipal solid waste under the influence of n-pentanol addition, cold EGR, and injection timing.

Abstract: Urban planning and development is a decisive factor that increases the automobile numbers which leads to increased energy demand across the globe. In order to meet the escalating requirements of energy, it is necessary to find viable alternatives. Waste plastic oil (WPO) is one such alternative which has dual benefits as it reduces the environmental pollution caused by plastic waste and it could possibly meet the energy requirement along with fossil fuels. The study attempted to reduce emissions from a DI diesel engine fueled with WPO using 30% by volume of n-pentanol with fossil diesel (WPO70P30). EGR (10, 20, and 30%) and injection timing modifications were made with the intention to find optimum engine operating conditions. The experimental results indicated that addition of renewable component like n-pentanol had improved the combustion characteristics by igniting WPO more homogeneously producing a higher premixed combustion phase. Smoke density for WPO70P30 was found to be twice lower than that of neat WPO at standard injection timing of 23°CA bTDC at any given EGR rate, NOx emissions were slightly on the higher side about 12% for WPO70P30 blend against WPO at same operating conditions. WPO70P30 showed lowest smoke and carbon monoxide emissions than diesel and WPO while delivering BTE’s higher than WPO and closer to diesel at all EGR and injection timings. However NOx and HC emissions increased with n-pentanol addition. The use of EGR reduced NOx emissions but was found to aggravate other emissions. It was concluded WPO70P30 can be favorably used in a DI diesel engine at the engines advanced injection timing for better performance than diesel with a slight penalty in NOx emissions.

Neuroprotective role of Asiatic acid in aluminium chloride induced rat model of Alzheimer's disease.

Abstract: Alzheimer's disease (AD) is the most common form of dementia, characterized by memory loss, cognitive impairment and personality disorders accompanied by diffuse structural abnormalities in the brain of elderly people. The current investigation explored the neuroprotective potential of asiatic acid (AA), a natural triterpene of Centella asiatica on aluminium chloride (AlCl3) induced rat model of AD. Oral administration of AlCl3 (100 mg/kg b.w.) for 42 days significantly elevated the levels of Al, activity of acetyl cholinesterase and expressions of amyloid precursor protein, amyloid beta1-42, beta and gamma secretases, glial fibrillary acidic protein, ionized calcium binding adaptor molecule 1, interleukins -1β, 6, 4, 2, tumor necrosis factor alpha, inducible nitric oxide synthase, nuclear factor- k beta and cyclooxygenase-2 in the hippocampus and cortex compared to the control group. Our observations suggested that AA treatment mitigated AlCl3 induced AD associated pathologies, which might be due to its multiple pharmacological actions. Further studies are necessary in order to explore the link between AlCl3-mediated oxidative stress and associated apoptosis to establish its neuroprotective role in AD.