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Methanolic extracts of Withania somnifera leaves, fruits and roots possess antioxidant properties and antibacterial activities  [cached]
Alam Nadia,Hossain Monzur,Mottalib Md,Sulaiman Siti
BMC Complementary and Alternative Medicine , 2012, DOI: 10.1186/1472-6882-12-175
Abstract: Background Withania somnifera, also known as ashwagandha, is an important herb in ayurvedic and indigenous medical systems. The present study was designed to evaluate the antioxidant and antibacterial activities of an 80% aqueous methanolic extract of W. somnifera roots (WSREt), fruits (WSFEt) and leaves (WSLEt). Methods Several assays were performed to determine the antioxidant properties of this herb including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP), ferrous chelation and inhibition of β-carotene bleaching. Results The values for DPPH, FRAP, ferrous chelation and inhibition of β carotene bleaching for the three types of extracts ranged from 101.73-801.93 μg/ml, 2.26-3.29 mM Fe/kg, 0.22-0.65 mg/ml and 69.87-79.67%, respectively, indicating that W. somnifera, particularly the leaves, possesses significant antioxidant properties. The mean ascorbic acid content was 20.60-62.60 mg/100 g, and the mean anthocyanin content was 2.86-12.50 mg/100 g. Antibacterial activities were measured using the agar well diffusion method and five pathogenic Gram-negative bacteria: Escherichia coli, Salmonella typhi, Citrobacter freundii, Pseudomonas aeruginosa and Klebsiella pneumoniae. The leaf extracts displayed the highest activity against S. typhi (32.00 ± 0.75 mm zone of inhibition), whereas the lowest activity was against K. pneumoniae (19.00 ± 1.48 mm zone of inhibition). The lowest minimum inhibitory concentration value was 6.25 mg/ml, which was against S. typhi, followed by 12.5 mg/ml against E. coli. Conclusion In addition to its antioxidant properties, W. somnifera exhibited significant antibacterial activities against Gram-negative bacteria, particularly S. typhi.
Chemical constituents of the ethyl acetate extracts of the stem bark and fruits of Dichrostachys cinerea and the roots of Parkia bicolor  [cached]
J. Fotie,A.E. Nkengfack,M.G. Peter,M. Heydenreich
Bulletin of the Chemical Society of Ethiopia , 2004,
Abstract: The antibacterial activities of ethyl acetate, methanol and aqueous extracts of the stem bark of Dichrostachys cinerea and the roots of Parkia bicolor have been evaluated. Ethyl acetate extracts have been investigated, studies that led to a series of known compounds, amongst which many are reported here for the very first time from both the species.
Chemical constituents of the ethyl acetate extracts of the stem bark and fruits of Dichrostachys cinerea and the roots of Parkia bicolor
J. Fotie, A.E. Nkengfack, M.G. Peter, M. Heydenreich, Z.T. Fomum
Bulletin of the Chemical Society of Ethiopia , 2004,
Abstract: The antibacterial activities of ethyl acetate, methanol and aqueous extracts of the stem bark of Dichrostachys cinerea and the roots of Parkia bicolor have been evaluated. Ethyl acetate extracts have been investigated, studies that led to a series of known compounds, amongst which many are reported here for the very first time from both the species. KEY WORDS: Dichrostachys cinerea, Parkia bicolor, Chemical constituents, Antibacterial activity Bull. Chem. Soc. Ethiop. 2004, 18(1), 111-115.
EVALUATION OF NEPHRO-PROTECTIVE AND ANTI-NEPHRO-TOXIC PROPERTIES OF RAKTA PUNARNAVA ROOTS (Boerhaavia diffusa, L.) GOKSHUR FRUITS (Tribulus terrestris, L.) IN DRUG INDUCED NEPHROTOXICITY  [PDF]
Kulkarni Yogini Ramachandra,Apte Bhalchandra Keshav,Kulkarni Pandurang Hari,Patil Ragini Rajan
International Research Journal of Pharmacy , 2012,
Abstract: Kwath of Rakta Punarnava roots (Boerhaavia diffusa, L.) and Gokshur fruits (Tribulus terrestris,L.) were tried for their Nephro-protective and anti-nephro-toxic properties by using Gentamycin induced Nephro-toxic model in Wistar strain Albino Rats. The effects were assessed on the basis of Biochemical and Histo-pathological investigations. Both the selected drugs have proven statistically significant results as Nephro-protective agent whereas Punarnava has got pronounced anti-nephro-toxic action too.
Decoherence without decoherence  [PDF]
Steven Weinstein
Physics , 2009,
Abstract: It has been claimed that decoherence of open quantum systems explains the tendency of macroscopic systems to exhibit quasiclassical behavior. We show that quasiclassicality is in fact an unremarkable property, characterizing generic subsystems of environments even in the absence of dynamical decoherence. It is suggested that decoherence is best regarded as explaining the persistence of true classicality, rather than the emergence, rather than the emergence of quasiclassicality.
Environmental Decoherence versus Intrinsic Decoherence  [PDF]
P. C. E. Stamp
Physics , 2012, DOI: 10.1098/rsta.2012.0162
Abstract: We review the difference between standard environmental decoherence and 'intrinsic decoherence', which is taken to be an ineluctable process of Nature. Environmental decoherence is typically modeled by spin bath or oscillator modes - we review some of the unanswered questions not captured by these models, and also the application of them to experiments. Finally, a sketch is given of a new theoretical approach to intrinsic decoherence, and this scheme is applied to the discussion of gravitational decoherence.
The decoherence criterion  [PDF]
Eleonora Alfinito,Rosario G. Viglione,Giuseppe Vitiello
Physics , 2000, DOI: 10.1142/S0217984901001410
Abstract: The decoherence mechanism signals the limits beyond which the system dynamics approaches the classical behavior. We show that in some cases decoherence may also signal the limits beyond which the system dynamics has to be described by quantum field theory, rather than by quantum mechanics.
Gravitational decoherence  [PDF]
Pieter Kok,Ulvi Yurtsever
Physics , 2003, DOI: 10.1103/PhysRevD.68.085006
Abstract: We investigate the effect of quantum metric fluctuations on qubits that are gravitationally coupled to a background spacetime. In our first example, we study the propagation of a qubit in flat spacetime whose metric is subject to flat quantum fluctuations with a Gaussian spectrum. We find that these fluctuations cause two changes in the state of the qubit: they lead to a phase drift, as well as the expected exponential suppression (decoherence) of the off-diagonal terms in the density matrix. Secondly, we calculate the decoherence of a qubit in a circular orbit around a Schwarzschild black hole. The no-hair theorems suggest a quantum state for the metric in which the black hole's mass fluctuates with a thermal spectrum at the Hawking temperature. Again, we find that the orbiting qubit undergoes decoherence and a phase drift that both depend on the temperature of the black hole. Thirdly, we study the interaction of coherent and squeezed gravitational waves with a qubit in uniform motion. Finally, we investigate the decoherence of an accelerating qubit in Minkowski spacetime due to the Unruh effect. In this case decoherence is not due to fluctuations in the metric, but instead is caused by coupling (which we model with a standard Hamiltonian) between the qubit and the thermal cloud of Unruh particles bathing it. When the accelerating qubit is entangled with a stationary partner, the decoherence should induce a corresponding loss in teleportation fidelity.
Universality of Decoherence  [PDF]
Daniel Braun,Fritz Haake,Walter T. Strunz
Physics , 2000, DOI: 10.1103/PhysRevLett.86.2913
Abstract: We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$ of the isolated system. While the golden rule then does not apply we can discard $H_{\rm sys}$. By allowing for simultaneous couplings to different reservoirs, we reveal decoherence as a universal short-time phenomenon independent of the character of the system as well as the bath and of the basis the superimposed states are taken from. We discuss consequences for the classical behavior of the macroworld and quantum measurement: For the decoherence of superpositions of macroscopically distinct states the system Hamiltonian is always negligible.
Deconstructing Decoherence  [PDF]
J. R. Anglin,J. P. Paz,W. H. Zurek
Physics , 1996, DOI: 10.1103/PhysRevA.55.4041
Abstract: The study of environmentally induced superselection and of the process of decoherence was originally motivated by the search for the emergence of classical behavior out of the quantum substrate, in the macroscopic limit. This limit, and other simplifying assumptions, have allowed the derivation of several simple results characterizing the onset of environmentally induced superselection; but these results are increasingly often regarded as a complete phenomenological characterization of decoherence in any regime. This is not necessarily the case: The examples presented in this paper counteract this impression by violating several of the simple ``rules of thumb''. This is relevant because decoherence is now beginning to be tested experimentally, and one may anticipate that, in at least some of the proposed applications (e.g., quantum computers), only the basic principle of ``monitoring by the environment'' will survive. The phenomenology of decoherence may turn out to be significantly different.
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