Platelet-Activating Factor (PAF) Antagonistic Activity of a New Biflavonoid from <em>Garcinia nervosa</em> var. <em>pubescens</em> King

The methanol extract of the leaves of Garcinia nervosa var. pubescens King, which showed strong inhibitory effects on platelet-activating factor (PAF) receptor binding, was subjected to bioassay-guided isolation to obtain a new biflavonoid, II-3,I-5, II-5,II-7,I-4',II-4'-hexahydroxy-(I-3,II-8)-flavonylflavanonol together with two known flavonoids, 6-methyl-4'-methoxyflavone and acacetin. The structures of the compounds were elucidated by spectroscopic methods. The compounds were evaluated for their ability to inhibit PAF receptor binding to rabbit platelets using ³H-PAF as a ligand. The biflavonoid and acacetin showed strong inhibition with IC₅₀ values of 28.0 and 20.4 μM, respectively. The results suggest that these compounds could be responsible for the strong PAF antagonistic activity of the plant.     

Systems of nonlinear Volterra integro-differential equations

An efficient method based on operational Tau matrix is developed, to solve a type of system of nonlinear Volterra integro-differential equations (IDEs). The presented method is also modified for the problems with separable kernel. Error estimation of the new schemes are analyzed and discussed. The advantages of this approach and its modification is that, the solution can be expressed as a truncated Taylor series, and the error function at any stage can be estimated. Methods are applied on the four problems with separable kernel to show the applicability and efficiency of our schemes, specially for those problems at broad intervals.     

N-lump and interaction solutions of localized waves to the (2 + 1)-dimensional asymmetrical Nizhnik–Novikov–Veselov equation arise from a model for an incompressible fluid

The present article deals with M-soliton solution and N-soliton solution of the (2 + 1)-dimensional asymmetrical Nizhnik–Novikov–Veselov equation by virtue of Hirota bilinear operator method. The obtained solutions for solving the current equation represent some localized waves including soliton, breather, lump, and their interactions, which have been investigated by the approach of the long-wave limit. Mainly, by choosing the specific parameter constraints in the M-soliton and N-soliton solutions, all cases of the one breather or one lump can be captured from the two, three, four, and five solitons. In addition, the performances of the mentioned technique, namely, the Hirota bilinear technique, are substantially powerful and absolutely reliable to search for new explicit solutions of nonlinear models. Meanwhile, the obtained solutions are extended with numerical simulation to analyze graphically, which results in localized waves and their interaction from the two-, three-, four-, and five-soliton solutions profiles. They will be extensively used to report many attractive physical phenomena in the fields of acoustics, heat transfer, fluid dynamics, classical mechanics, and so on.     

Suppression of Pulmonary Tumor Promotion and Induction of Apoptosis by <Emphasis Type="Italic">Crocus sativus</Emphasis> L. Extraction

Crocus sativus L., commonly known as saffron, is the raw material for one of the most expensive spice in the world, and it has been used in folk medicine for centuries. We investigated the potential of the ethanolic extract of saffron to induce cytotoxic and apoptosis effects in carcinomic human alveolar basal epithelial cells (A549), a commonly used cell culture system for in vitro studies on lung cancer. The cells were cultured in Dulbecco’s modified Eagle’s medium with 10% fetal bovine serum treated with different concentrations of the ethanolic extract of saffron for two consecutive days. Cell viability was quantitated by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Apoptotic cells were determined using annexin V–fluorescein isothiocyanate by flow cytometry. Saffron could decrease the cell viability in the malignant cells as a concentration- and time-dependent manner. The IC₅₀ values against the A549 cell lines were determined as 1,200 and 650 μg/ml after 24 and 48 h, respectively. Saffron-induced apoptosis of the A549 cells in a concentration-dependent manner, as determined by flow cytometry histogram of treated cells that induced apoptotic cell death, is involved in the toxicity of saffron. It might be concluded that saffron could cause cell death in the A549 cells, in which apoptosis plays an important role. Saffron could also be considered as a promising chemotherapeutic agent in lung cancer treatment in future.     

New Insights into Molecular Mechanism behind Anti-Cancer Activities of Lycopene

Lycopene is a well-known compound found commonly in tomatoes which brings wide range of health benefits against cardiovascular diseases and cancers. From an anti-cancer perspective, lycopene is often associated with reduced risk of prostate cancer and people often look for it as a dietary supplement which may help to prevent cancer. Previous scientific evidence exhibited that the anti-cancer activity of lycopene relies on its ability to suppress oncogene expressions and induce proapoptotic pathways. To further explore the real potential of lycopene in cancer prevention, this review discusses the new insights and perspectives on the anti-cancer activities of lycopene which could help to drive new direction for research. The relationship between inflammation and cancer is being highlighted, whereby lycopene suppresses cancer via resolution of inflammation are also discussed herein. The immune system was found to be a part of the anti-cancer system of lycopene as it modulates immune cells to suppress tumor growth and progression. Lycopene, which is under the family of carotenoids, was found to play special role in suppressing lung cancer.     

Tension spline solution of nonlinear sine-Gordon equation

The sine-Gordon equation plays an important role in modern physics. By using spline function approximation, two implicit finite difference schemes are developed for the numerical solution of one-dimensional sine-Gordon equation. Stability analysis of the method has been given. It has been shown that by choosing the parameters suitably, we can obtain two schemes of orders O(k²+k²h²+h²)\mathcal{O}(k^{2}+k^{2}h^{2}+h^{2}) and O(k²+k²h²+h⁴)\mathcal{O}(k^{2}+k^{2}h^{2}+h^{4}). At the end, some numerical examples are provided to demonstrate the effectiveness of the proposed schemes.     

Spin-flip assisted tunneling through quantum dot based magnetic tunnel junctions

We theoretically study the spin-polarized transport through double barrier magnetic tunnel junction (DBMTJ) consisting of the quantum dot sandwiched by two ferromagnetic (FM) leads. The tunneling current through the DBMTJ is evaluated based on the Keldysh nonequilibrium Green’s function approach. The self-energy and Green’s function of the dot are analytically obtained via the equation of motion method, by systematically incorporating two spin-flip phenomena, namely, intra-dot spin-flip, and spin-flip coupling between the lead and the central dot region. The effects of both spin-flip processes on the spectral functions, tunneling current and tunnel magnetoresistance (TMR) are analyzed. The spin-flip effects result in spin mixing, thus contributing to the spectral function of the off-diagonal Green’s function components ( G_s[`(s)] ^r )\left( {G_{\sigma \bar \sigma }^r } \right). Interestingly, the spin-flip coupling between the lead and dot enhances both the tunneling current and the TMR for applied bias above the threshold voltage V _th . On the other hand, the intra-dot spin-flip results in an additional step in the I-V characteristics near V _th . Additionally, it suppresses the tunneling current but enhances the TMR. The opposing effects of the two types of spin-flip on the tunneling current means that one spin-flip mechanism can be engineered to counteract the other, so as to maintain the tunneling current without reducing the TMR. Their additive effect on the TMR enables the DBMTJ to attain a large tunneling current and high TMR for above threshold bias values.     

Synthesis of new 2‐ferrocenyl‐5‐fluoro‐6‐(4‐substituted‐1‐piperazinyl)‐1H‐benzimidazoles of potential biological interest

New substituted 2‐ferrocenylbenzimidazole derivatives are prepared by the oxidation of corresponding Schiff's bases in situ, generated from corresponding 1,2‐diamino‐4‐fluoro‐5‐(1‐piperazinyl)benzenes and 2‐ferrocenecarboxaldehyde using nitrobenzene.     

Improving the high variable bioavailability of griseofulvin by SEDDS

To enhance the dissolution and oral absorption of poorly water-soluble griseofulvin (GF), self-emulsifying drug delivery system (SEDDS) composed of oil, surfactant and cosurfactant for oral administration of griseofulvin was formulated, and its physicochemical properties and pharmacokinetic parameters were evaluated. The solubility of griseofulvin was further improved by the addition of hydrochloric acid. Droplet size of griseofulvin emulsion was kept constant both in simulated gastric fluid without pepsin and simulated intestinal fluid throughout 12 weeks incubation period. Griseofulvin in the SEDDS rapidly dissolved in different dissolution media. This was not the case for the commercial GRIS-PEG tablets. In different fed diet groups, AUC 0-->24 h, Cp max, and T max of griseofulvin after oral administration of SEDDS in rats were comparable to those after oral dose of GRIS-PEG tablet. Although, in fed lipidic diet group, the mean AUC and Cp max after oral administration of GRIS-PEG in rats were 1.28 and 1.15 fold higher, respectively, compared with those of SEDDS, these have not shown to be significantly different. These results demonstrate that the SEDDS of griseofulvin composed of Capmul GMO-50, Poloxamer and Myvacet 9-45 greatly enhanced the dissolution of griseofulvin (without ultramicronisation). However, food intake effect on the bioavailability of griseofulvin has remained. Thus, this system may provide a useful dosage form for oral water-insoluble drugs which have problems in their dissolution.