Phenolic compounds from Eucalyptus gomphocephala with potential cytotoxic and antioxidant activities

Two new phenolic compounds, 2,4,6-trihydroxy-5-methyl-acetophenone 2-O-beta-D-glucopyranoside (3), and benzyl alcohol 7-O-(3',4',6'-tri-O-galloyl)-beta-D-glucopyranoside (8), together with eight known phenolic compounds, were isolated from the 70% aqueous acetone extract of Eucalyptus gomphocephala DC. (Myrtaceae). The isolated compounds were elucidated based on their 1H, 13C, DQF-COSY, selective 1D-TOCSY, HSQC, and HMBC NMR spectroscopic and ESI-MS data. The antioxidant effect of the phenolic compounds was tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical and super oxide anion radical scavenging assays. The cytotoxicity of the isolated compounds was evaluated using HeLa cell line.     

Novel diphenylamine 2,4'-dicarboxamide based azoles as potential epidermal growth factor receptor inhibitors: synthesis and biological activity

Several hybrid molecules of diphenylamine-2,4'-dicarboxamide with various azolidinones and related heterocyclic rings have been synthesized and explored as epidermal growth factor receptor (EGFR) kinase inhibitors. Most of them displayed promising in vitro tyrosine kinase inhibition as well as potent cellular antiproliferative activity in the EGFR over-expressing breast cancer cell line (MCF-7). Compounds 12b and 13b that exhibited the highest inhibition in the kinase assay (89, 81% inhibition at 10 μM, respectively), showed potent antiproliferative effect against MCF-7 tumor cell line (IC(50) 1.04, 0.91 μM respectively). Molecular docking studies revealed that these compounds can bind to ATP binding site of the EGFR kinase domain and were involved in H-bonding with Met 793, in analogy to the known EGFR tyrosine kinase inhibitors. Moreover, compounds 15a-c possessed profound antitumor activity (IC(50) 0.59-0.73 μM) and significant EGFR-TK inhibition, making them of particular interest. In summary, the newly synthesized compounds provide promising new lead for the future design and development of anticancer agents of potential EGFR-TK inhibitory activity.     

Spectrofluorimetric and Spectrophotometric Stability‐Indicating Methods for the Analysis of Veralipride in Presence of Its Degradants and in Spiked Human Plasma

Spectrofluorimetric and spectrophotometric stability‐indicating methods were developed and validated for analysis of veralipride (Ver) in presence of its hydrolytic and oxidative degradants. The spectrofluorimetric method was based on direct measurement of the intrinsic fluorescence of Ver at 366 nm after excitation at 299 nm using sodium lauryl sulfate (SLS) as micelle enhancer. The fluorescence intensity plot was linear over the concentration range 1.0–10.0 µg·mL^?1. The high sensitivity of the method allowed its successful application to the analysis of Ver in spiked human plasma. Two other methods were developed. They are based on the oxidative coupling reaction of Ver with 3‐methyl benzothiazolin‐2‐one hydrazone (MBTH) hydrochloride in presence of ceric ammonium sulphate in an acidic medium. The first method depends on spectrophotometric measurement of the stable green colored oxidative coupling product at 660 nm. The different experimental parameters affecting the reaction were optimized. Linearity range is 10.0–100.0 µg·mL^?1. The second method depends on a fluorescence quenching effect of Ver on the fluorescence of Ce³⁺. The difference in fluorescence intensity was measured at 380 nm after excitation at 300 nm. This method is applicable over the concentration ranges 0.25–2.50 µg·mL^?1. The methods were validated according to the ICH guidelines. They were successfully applied for the analysis of Ver in drug substance, drug product and in laboratory prepared mixtures containing different percentages of hydrolytic and oxidative degradants.     

Period-three route to chaos induced by a cyclic-fold bifurcation in passive dynamic walking of a compass-gait biped robot

This paper presents a study of the passive dynamic walking of a compass-gait biped robot as it goes down an inclined plane. This biped robot is a two-degrees-of-freedom mechanical system modeled by an impulsive hybrid nonlinear dynamics with unilateral constraints. It is well-known to possess periodic as well as chaotic gaits and to possess only one stable gait for a given set of parameters. The main contribution of this paper is the finding of a window in the parameters space of the compass-gait model where there is multistability. Using constraints of a grazing bifurcation on the basis of a shooting method and the Davidchack–Lai scheme, we show that, depending on initial conditions, new passive walking patterns can be observed besides those already known. Through bifurcation diagrams and Floquet multipliers, we show that a pair of stable and unstable period-three gait patterns is generated through a cyclic-fold bifurcation. We show also that the stable period-three orbit generates a route to chaos.     

Validated Densitometric TLC Method for Analysis of (R)- and (S)-Bupivacaine,Using Cyclodextrin Derivatives as Chiral Selectors

JPC – Journal of Planar Chromatography – Modern TLC - Anovel economic procedure for stereospecific separation and analysis of (R)-and (S)-bupivacaine has been developed and validated....     

Spectrofluorimetric and spectrophotometric stability-indicating methods for determination of some oxicams using 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl)

Two sensitive and selective spectrofluorimetric and spectrophotometric stability-indicating methods have been developed for the determination of some non-steroidal anti-inflammatory oxicam derivatives namely lornoxicam (Lx), tenoxicam (Tx) and meloxicam (Mx) after their complete alkaline hydrolysis. The methods are based on derivatization of alkaline hydrolytic products with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The products showed an absorption maximum at 460 nm for the three studied drugs and fluorescence emission peak at 535 nm in methanol. The color was stable for at least 48 h. The optimum conditions of the reaction were investigated and it was found that the reaction proceeds quantitatively at pH 8, after heating in a boiling water bath for 30 min. The methods were found to be linear in the ranges of 1-10 microg ml(-1) for Lx and Tx and 0.5-4.0 microg ml(-1) for Mx for spectrophotometric method, while 0.05-1.0 microg ml(-1) for Lx and Tx and 0.025-0.4 microg ml(-1) for Mx for the spectrofluorimetric method. The validity of the methods was assessed according to USP guidelines. Statistical analysis of the results revealed high accuracy and good precision. The suggested procedures could be used for the determination of the above mentioned drugs in pure and dosage forms as well as in the presence of their degradation products.     

Ion solvation in 3-methyl-2-oxazolidone

In continuing previous studies of the solvation behavior of electrolytes in nonaqueous media, a series of tetraalkylammonium tetraphenylborates, cesium and rubidium tetraphenylborates, tetraalkylammonium perchlorates, and tetraphenylarsonium chloride were investigated by proton magnetic resonance spectroscopy in 3-methyl-2-oxazolidone, a solvent with high dielectric constant, high polarity, and wide liquid range. In this study, as in a previous investigation, it was found that salt solutions containing the tetraphenylborate anion were found to shift the proton peaks upfield, indicating an increase in electron density around solvent protons. In this study the same effect has been noted for tetraphenylborate as well as tetraphenylarsonium ion and is attributed to the large diamagnetic anisotropy of the aromatic solute molecules which results in circulation of electrons induced by the magnetic field. This ring current causes shielding of the solvent protons, and the shielding increases as the concentration of aromatic solute increases, resulting in upfield morement of chemical shift irrespective of whether the aromatic moiety is the cation or anion.     

The Real Powers of the Convolution of a Gamma Distribution and a Bernoulli Distribution

In this paper, we essentially compute the set of x,y>0 such that the mapping \(z\longmapsto(1-r+re^{z})^{x}(\frac{\lambda}{\lambda-z})^{y}\) is a Laplace transform. If X and Y are two independent random variables which have respectively Bernoulli and Gamma distributions, we denote by μ the distribution of X+Y. The above problem is equivalent to finding the set of x>0 such that μ ^*x exists.     

Evaluation of the Effect of Elite Jojoba Lines on the Chemical Properties of their Seed Oil

Jojoba oil (JO) extracted from seeds has outstanding properties, including anti-inflammatory, antioxidant, and antibacterial activities, and can be stored forlong periodsof time. The unique properties of jojoba oil depend on its chemical composition; therefore, the effect of the jojoba genotype on the chemical properties and active components of the seed oil was evaluated in this study. Oil samples were collected from 15 elite Egyptian jojoba lines. The chemical composition, such as moisture, crude fiber, crude oil, ash, and crude protein of elite lines’ seeds was determined to investigate the variation among them based on the jojoba genotype. In addition, the iodine value was obtained to measure the degree of jojoba oil unsaturation, whereas the peroxide number was determined as an indicator of the damage level in jojoba oil. Fatty acid composition was studied to compare elite jojoba lines. Fatty acid profiles varied significantly depending on the jojoba genotype. Gadoleic acid exhibited the highest percentage value (67.85–75.50%) in the extracted jojoba oil, followed by erucic acid (12.60–14.81%) and oleic acid (7.86–10.99%). The iodine value, peroxide number, and fatty acid composition of the tested elite jojoba lines were compared withthose reported by the International Jojoba Export Council (IJEC). The results showed that the chemical properties of jojoba oils varied significantly, depending on the jojoba genotype.