Aligarh Muslim University

About: Aligarh Muslim University is a education organization based out in Aligarh, Uttar Pradesh, India. It is known for research contribution in the topics: Population & Adsorption. The organization has 8218 authors who have published 16416 publications receiving 289068 citations. The organization is also known as: AMU.

Redox cycling of endogenous copper by thymoquinone leads to ROS-mediated DNA breakage and consequent cell death: putative anticancer mechanism of antioxidants.

Abstract: Plant-derived dietary antioxidants have attracted considerable interest in recent past for their chemopreventive and cancer therapeutic abilities in animal models. Thymoquinone (TQ) is the major bioactive constituent of volatile oil of Nigella sativa and has been shown to exert various pharmacological properties, such as anti-inflammatory, cardiovascular, analgesic, anti-neoplastic, anticancer and chemopreventive. Although several mechanisms have been suggested for the chemopreventive and anticancer activity of TQ, a clear mechanism of action of TQ has not been elucidated. TQ is a known antioxidant at lower concentrations and most of the studies elucidating the mechanism have centered on the antioxidant property. However, recent publications have shown that TQ may act as a prooxidant at higher concentrations. It is well known that plant-derived antioxidants can switch to prooxidants even at low concentrations in the presence of transition metal ions such as copper. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Copper is an important metal ion present in the chromatin and is closely associated with DNA bases, particularly guanine. Using human peripheral lymphocytes and comet assay, we first show that TQ is able to cause oxidative cellular DNA breakage. Such a DNA breakage can be inhibited by copper-chelating agents, neocuproine and bathocuproine, and scavengers of reactive oxygen species. Further, it is seen that TQ targets cellular copper in prostate cancer cell lines leading to a prooxidant cell death. We believe that such a prooxidant cytotoxic mechanism better explains the anticancer activity of plant-derived antioxidants.

An efficient micropropagation system for Tylophora indica: an endangered, medicinally important plant

Abstract: An efficient protocol is described for the rapid in vitro multiplication of an endangered medicinal plant, Tylophora indica (Burm. f.) Merrill, via enhanced axillary bud proliferation from nodal explants collected from young shoots of a two-year-old plant. The physiological effects of growth regulators [6-benzyladenine (BA), kinetin (Kin) thidiazuron (TDZ), indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) or α-naphthalene acetic acid (NAA)], ascorbic acid (AA), different strengths of Murashige and Skoog (MS) medium and various pH levels on in vitro morphogenesis were investigated. The highest number (8.6 ± 0.71) of shoots and the maximum average shoot length (5.2 ± 0.31 cm) were recorded on MS medium supplemented with 2.5 μM BA, 0.5 μM NAA and 100 mg/l AA at pH 5.8. Rooting was best achieved on half-strength MS medium augmented with 0.5 μM IBA. The plantlets regenerated in vitro with well-developed shoot and roots were successfully established in pots containing garden soil and grown in a greenhouse with a 90% survival rate. The regenerated plants did not show any immediate detectable phenotypic variation. The described method can be successfully employed for large-scale multiplication and long-term in vitro conservation of T. indica.

Nanostructured semiconducting materials for efficient hydrogen generation

Abstract: Massive production of hydrogen by water decomposition triggered by a solar light active photocatalyst is a major objective in chemistry and a promising avenue to overcome the global energy crisis. The development of efficient, stable, economically viable and eco-friendly photocatalysts for hydrogen production is a challenging task. This article reviews the use of nanocomposite in three combinations: metal oxide–metal oxide semiconductor, metal–metal oxide semiconductor and metal chalcogenide–metal oxide core–shell nanostructures. These core–shell structures occur in two forms: a simple form where the photocatalyst is either in the core or the shell or in a more complex system where the core–shell structure comprises a co-catalyst deposited on a semiconducting material. We discuss the design, synthesis and development of semiconductor-based nanocomposite photocatalysts for hydrogen production. The major points are the role of catalytic active sites, the chemical nature of sacrificial agents, the effect of light sources, the variable light intensity and the energy efficiency calculation. For TiO2-based nanocomposites, the metal oxide or metal co-catalyst loading of 1.0–3.0 wt% was optimal. TiO2 nanotube–CuO hybrid nanocomposites produce 1,14,000 µmol h−1 $${\text{g}}^{ - 1}_{\text{cat}}$$ , whereas TiO2/Au nanocomposites display 1,60,000 µmol h−1 $${\text{g}}^{ - 1}_{\text{cat}}$$ . For core–shell catalysts, a shell thickness of 2–20 nm was found for the best activity, and its performance is as follows: (a) CdS–NiO system produces around 19,949 µmol h−1 $${\text{g}}^{ - 1}_{\text{cat}}$$ and (b) CuO–Cr2O3 as co-catalyst immobilized on TiO2 system produces around 82,390 µmol h−1 $${\text{g}}^{ - 1}_{\text{cat}}$$ .

Land-use change and its socio-environmental impact in Eastern Ethiopia’s highland

Abstract: The Alemaya district (Eastern Ethiopian highlands) is characterized by undulating physiographic features with arid, semi-arid, and humid climatic conditions. This study evaluated socio-environmental changes in land use and land cover during 1985–2011. Screen digitization on remotely sensed data (i.e., Landsat images from 1985 to 2011) was performed to produce 10 classes of land use and land cover. Then, final land-use maps were prepared using a geographic information system following field verification and accuracy assessment. The drying of water bodies, including the prominent lakes Alemaya, Adele, and Tinike, had been the most important environmental change observed. Degraded land, marsh, perennial cropland, and residential areas increased by 37, 438, 42, and 190 %, respectively, whereas grassland, plantation, shrubland, and temporal cropland decreased by 64, 11, 63, and 29 %, respectively. The increase in land degradation (+37 %), the other major observed problem, has made large areas unsuitable for agriculture and has reduced crop productivity. These land-use and land-cover changes have affected both the environment and the livelihoods of local residents; especially the issue related to land degradation requires urgent attention.

Type 2 diabetes mellitus: Role of melatonin and oxidative stress.

Abstract: Type 2 diabetes mellitus caused by transfer of susceptible immortal gene from parent to progeny in individuals prone, and/or in contribution of factors such as obesity and physical inactivity results in chronic extracellular hyperglycemia due to insulin resistance or impaired glucose tolerance. Hyperglycemia leads to increased production of superoxide radical in mitochondrial electron transport chain, consequently, inhibit glyceraldehyde-3-phosphate dehydrogenase activity, increase the flux of substrates that direct the expression of genes responsible for activation of polyol, hexosamine, advanced glycation end products and protein kinase-C pathways enzymes. Simultaneously, these pathways add-up free radicals in the body, hamper cell redox state, alter genes of insulin sensitivity and are responsible for the diabetic complications like retinopathy, atherosclerosis, cardiovascular diseases, nephropathy and neuropathy. Experimental evidence suggests that the indoleamine hormone melatonin is capable of influencing in development of diabetic complications by neutralizing the unnecessary production of ROS, protection of beta cells, as they possess low antioxidant potential and normalize redox state in the cell. However, studies reported the beneficial effects of pharmacological supplementation of melatonin in humans but it has not been extensively studied in a multicountric, multicentric which should include all ethnic population.