Anti-HIV-1 and cytotoxicity of the alkaloids of Erythrina abyssinica Lam. growing in Sudan

Erythrina abyssinica Lam. is an important medicinal plant growing in Sudan; its seeds were investigated for the first time for their alkaloidal constituents and biological activity. The in vitro cytotoxicity of the crude alkaloidal fraction (CAF) against the cell lines HeLa, Hep-G2, HEP-2, HCT116, MCF-7 and HFB4 showed promising activity, with IC?? values of 13.8, 10.1, 8.16, 13.9, 11.4 and 12.2?μg?mL?1, respectively. Doxorubicin (positive control) showed in vitro cytotoxic activity with IC?? values 3.64, 4.57, 4.89, 3.74, 2.97 and 3.96?μg?mL?1, respectively. Bioassay-guided fractionation and isolation of the CAF led to the isolation of five Erythrina alkaloids, identified as erythraline, erysodine, erysotrine, 8-oxoerythraline and 11-methoxyerysodine. These were evaluated for their in vitro cytotoxic activity against Hep-G2 which resulted in IC?? values 17.60, 11.80, 15.80, 3.89 and 11.40?μg?mL?1, respectively. Furthermore, in vitro cytotoxic activity against HEP-2 was evaluated, which resulted in IC?? values 15.90, 19.90, 21.60, 18.50 and 11.50?μg?mL?1, respectively. The CAF caused a reduction in the viability of mock-infected MT-4 cells with a CC?? of 53?μM and a 50% protection of MT-4 cells against HIV-1 induced cytopathogeneticy with a EC?? of >53?μM, compared with EFV as a positive control, which had a CC?? of 45?μM and an EC?? of 0.003?μM. We concluded that the isolated alkaloids were responsible for the carcinogenic actions of the plant extract previously reported in the literature.     

Development and validation of HPLC method for simultaneous estimation of piperine and guggulsterones in compound Unani formulation (tablets) and a nanoreservoir system

An attempt has been made to develop and validate a simultaneous HPLC method for novel approach of drug release via oil‐in‐water (o/w) nanoemulsion formulation and Habb‐e‐Khardal Unani tablet containing piperine and guggul sterones E and Z as main ingredients. Nanoemulsion was prepared by titration method using sefsol‐218 as an oily phase, cremophor‐EL as a surfactant, transcutol as a co‐surfactant and distilled water as an aqueous phase. The formulation was optimized on the basis of thermodynamic stability and dispersibilty test. The nanoformulation was evaluated for particle size, surface morphology, electrical conductivity and viscosity determination. The in vitro dissolution was carried out by dialysis bag method. Drugs were quantified using an HPLC method developed in‐house with a C₁₈ column as stationary phase and acetonitrile and water as mobile phase at λ_max of 240 nm. The optimized formulation showed higher drug release, lower droplet size and less viscosity as compared with the conventional Habb‐e‐Khardal Unani tablet. The present study illustrated the potential of nanoemulsion dosage form in improving biopharmaceutic performance of piperine and guggul sterone. The HPLC method was also found to be quite sufficient for the routine quality control of formulations containing piperine and guggul sterone E and Z as ingredients and also for in vitro drug release studies. Copyright © 2011 John Wiley & Sons, Ltd.     

Flexible microfluidic cloth-based analytical devices using a low-cost wax patterning technique

This paper describes the fabrication of microfluidic cloth-based analytical devices (μCADs) using a simple wax patterning method on cotton cloth for performing colorimetric bioassays. Commercial cotton cloth fabric is proposed as a new inexpensive, lightweight, and flexible platform for fabricating two- (2D) and three-dimensional (3D) microfluidic systems. We demonstrated that the wicking property of the cotton microfluidic channel can be improved by scouring in soda ash (Na(2)CO(3)) solution which will remove the natural surface wax and expose the underlying texture of the cellulose fiber. After this treatment, we fabricated narrow hydrophilic channels with hydrophobic barriers made from patterned wax to define the 2D microfluidic devices. The designed pattern is carved on wax-impregnated paper, and subsequently transferred to attached cotton cloth by heat treatment. To further obtain 3D microfluidic devices having multiple layers of pattern, a single layer of wax patterned cloth can be folded along a predefined folding line and subsequently pressed using mechanical force. All the fabrication steps are simple and low cost since no special equipment is required. Diagnostic application of cloth-based devices is shown by the development of simple devices that wick and distribute microvolumes of simulated body fluids along the hydrophilic channels into reaction zones to react with analytical reagents. Colorimetric detection of bovine serum albumin (BSA) in artificial urine is carried out by direct visual observation of bromophenol blue (BPB) colour change in the reaction zones. Finally, we show the flexibility of the novel microfluidic platform by conducting a similar reaction in a bent pinned μCAD.     

Applications of supercritical fluid extraction (SFE) of palm oil and oil from natural sources

Supercritical fluid extraction (SFE), which has received much interest in its use and further development for industrial applications, is a method that offers some advantages over conventional methods, especially for the palm oil industry. SC-CO? refers to supercritical fluid extraction (SFE) that uses carbon dioxide (CO?) as a solvent which is a nontoxic, inexpensive, nonflammable, and nonpolluting supercritical fluid solvent for the extraction of natural products. Almost 100% oil can be extracted and it is regarded as safe, with organic solvent-free extracts having superior organoleptic profiles. The palm oil industry is one of the major industries in Malaysia that provides a major contribution to the national income. Malaysia is the second largest palm oil and palm kernel oil producer in the World. This paper reviews advances in applications of supercritical carbon dioxide (SC-CO?) extraction of oils from natural sources, in particular palm oil, minor constituents in palm oil, producing fractionated, refined, bleached, and deodorized palm oil, palm kernel oil and purified fatty acid fractions commendable for downstream uses as in toiletries and confectionaries.     

Water-wire catalysis in photoinduced acid-base reactions

The pronounced ability of water to form a hyperdense hydrogen (H)-bond network among itself is at the heart of its exceptional properties. Due to the unique H-bonding capability and amphoteric nature, water is not only a passive medium, but also behaves as an active participant in many chemical and biological reactions. Here, we reveal the catalytic role of a short water wire, composed of two (or three) water molecules, in model aqueous acid-base reactions synthesizing 7-hydroxyquinoline derivatives. Utilizing femtosecond-resolved fluorescence spectroscopy, we tracked the trajectories of excited-state proton transfer and discovered that proton hopping along the water wire accomplishes the reaction more efficiently compared to the transfer occurring with bulk water clusters. Our finding suggests that the directionality of the proton movements along the charge-gradient H-bond network may be a key element for long-distance proton translocation in biological systems, as the H-bond networks wiring acidic and basic sites distal to each other can provide a shortcut for a proton in searching a global minimum on a complex energy landscape to its destination.     

Finding optimal finite field strengths allowing for a maximum of precision in the calculation of polarizabilities and hyperpolarizabilities

The finite field method, widely used for the calculation of static dipole polarizabilities or the first and second hyperpolarizabilities of molecules and polymers, is thoroughly explored. The application of different field strengths and the impact on the precision of the calculations were investigated. Borders could be defined and characterized, establishing a range of feasible field strengths that guarantee reliable numerical results. The quality of different types of meshes to screen the feasible region is assessed. Extrapolation schemes are presented that reduce the truncation error and allow to increase the precision of finite field calculations by one to three orders of magnitude. © 2013 Wiley Periodicals, Inc.     

Evaluation of Antimicrobial Activity of Some Newly Synthesized 4‐Thiazolidinones

The antimicrobial activity of thirteen newly synthesized 4‐thiazolidinones (TZONs) and four dithiolane derivatives was assessed against susceptible and resistant bacteria, including MRSA, as well as Candida albicans. The structure‐activity relationships revealed that 4‐Thiazolidinone derivatives harboring p‐chlorophenyl and dicarboxyethyl at the 2‐ethenyl and 5‐arylidine positions of the thiazolidinone ring display considerable antibacterial properties. No antifungal activity was recorded by all tested compounds against Candida albicans. The possible potentiative (synergistic) effect of the most active compounds to a few commercial antibiotics was also investigated.     

Evaluation of Antifungal and Antioxidant Activity of Newly Synthesized 4‐Thiazolidinones

The antifungal and antioxidant activities of thirty newly synthesized 4‐thiazolidinone (TZON) derivatives were assessed against some fungal species including Candida albicans and Aspergillus niger. The introduction of different arylidene moieties at 5‐positions of the thiazolidinone ring successfully enhanced its biological activity. The structure–activity relationships revealed that 4‐thiazolidinone derivatives harboring dicarboxyethyl (at the 2‐ethenyl) and p‐nitrophenylhydrazyl arm (at the 5‐arylidine positions of the thiazolidinone ring) display considerable antifungal and antioxidant properties.     

Synthesis of New Pyrazolo[1.5.4-de]quinoxalines

New pyrazolo[1.5.4-de]quinoxaline derivatives were prepared by the action of 7-aminoindazole 1 on diethyl and dimethyl acetylene dicarboxylates. The structures of the obtained compounds and the direction of cyclization were investigated through a crystallographic study of compound 2. Further alkylation, hydrogenation, and bromination were also explored. The action of potassium thiocyanate on the obtained halo product led to a tetracyclic compound of 1.3-thiazolo[3.4-a]pyrazolo[1.5.4-de]quinoxaline series.