The genus Machaerium (Fabaceae): taxonomy,phytochemistry, traditional uses and biological activities

Machaerium, in the family Fabaceae, predominantly is a genus of a Neotropical distribution of trees, shrubs, and lianas occurring from southern Mexico to Brazil and northern Argentina and as far as South America. Several Machaerium species are widely used in traditional medicine and are considered to have multiple medicinal properties. This review aims to provide up-to-date and comprehensive information on the taxonomy, phytochemistry, traditional uses and biological activities of plants in the genus Machaerium.     

A novel ferroin membrane sensor for potentiometric determination of iron

A novel potentiometric approach for both batch and flow injection determination of iron(II) and/or iron(III) is described. It is based on the formation and monitoring of ferroin with a PVC membrane sensor containing ferroin-TPB as an electroactive component plasticized with 2-nitrophenyl phenyl ether. The sensor exhibits fast Nernstian response for ferroin with a cationic calibration slope of 30 +/- 0.2 mV/concentration decade down to 4 x 10(-7)M ferroin (0.03 ppm Fe) at pH 3-9. Interferences from common inorganic cations are negligible or can be eliminated by a pretreatment with DDC. The ferroin sensor was successfully applied to the determination of iron contents in water, alloys, rocks and pharmaceuticals. The results show good correlation with data obtained by the standard spectrophotometric ferroin method, the coefficient of correlation is better than 0.7%.     

Development of a diamine biosensor

An amperometric diamine sensor is developed for clinical applications in diagnosis of bacterial vaginosis (BV). The sensor is based on crosslinked putrescine oxidase (PUO) which catalyzes the conversion of diamines (mainly putrescine and cadaverine) to products including hydrogen peroxide. The hydrogen peroxide is detected anodically at platinum electrode polarized at 0.5 V versus Ag/AgCl. Platinum-plated gold electrodes used as a substrate for the sensor construction, are batch-fabricated on a flexible polyimide foil (Kapton(R), DuPont). A three-electrode cell configuration is used in all amperometric measurements. The sensor construction is based on three layers: an inner layer to reject the interference effect of oxidizable molecules, an outer diffusion controlling layer, and in addition, an enzyme middle layer. The enzyme layer was immobilized by crosslinking PUO with bovine serum albumin (BSA) using glutaraldehyde (GA). An optimization study of the enzyme solution composition was carried out. With the optimized enzyme layer, the biosensor showed a very high sensitivity and fast response time of ca. 20 s. The sensor has a linear dynamic range from (0.5-300 muM) for putrescine that covers the expected biological levels of the analyte. Details on sensor fabrication and characterization are given in the present work.     

Design,Synthesis, Biological Evaluation,and Computational Studies of Novel Tri-Aryl Imidazole-Benzene Sulfonamide Hybrids as Promising Selective Carbonic Anhydrase IX and XII Inhibitors

A novel series of tri-aryl imidazole derivatives 5a–n carrying benzene sulfonamide moiety has been designed for their selective inhibitory against hCA IX and XII activity. Six compounds were found to be potent and selective CA IX inhibitors with the order of 5g > 5b > 5d > 5e > 5g > 5n (Ki = 0.3–1.3 μM, and selectivity ratio for hCA IX over hCA XII = 5–12) relative to acetazolamide (Ki = 0.03 μM, and selectivity ratio for hCA IX over hCA XII = 0.20). The previous sixth inhibitors have been further investigated for their anti-proliferative activity against four different cancer cell lines using MTT assay. Compounds 5g and 5b demonstrated higher antiproliferative activity than other tested compounds (with GI₅₀ = 2.3 and 2.8 M, respectively) in comparison to doxorubicin (GI₅₀ = 1.1 M). Docking studies of these two compounds adopted orientation and binding interactions with a higher liability to enter the active side pocket CA-IX selectively similar to that of ligand 9FK. Molecular modelling simulation showed good agreement with the acquired biological evaluation.     

Design,Synthesis, and Pharmacological Assay of Novel Compounds Based on Pyridazine Moiety as Potential Antitumor Agents

In an endeavor to develop antitumor agents, we made a credible survey regarding synthesis, structure, and pharmacological assay of novel pyridazine derivatives, so that 2‐((6‐(4‐chloro‐3‐methylphenyl)pyridazin‐3‐yl)oxy)acetohydrazide 3 was utilized as scaffold to build novel compounds 4 – 19 by reaction with various electrophilic reagents, followed by determination and explanation atropisomerism phenomena and tauomerism ratio such as keto‐enol and lactam–lactim tautomers for some synthesized compounds. In vitro, these compounds were screened for antitumor efficacy versus two cell lines, namely, hepatocellular carcinoma and mammary gland breast cancer, by using MTT assay. Among the examined compounds, compound 16 was exhibited promising potent activity (IC₅₀ = 8.67 ± 0.7 μM) versus HepG2 cell line. Meanwhile, compounds 3 and 16 were manifested the very highest efficacy (IC₅₀ = 5.68 ± 0.6 and 9.41 ± 0.9 μM) versus MCF‐7 cell line.     

Design,Synthesis, and Biological Evaluation of Novel Pyrazole,Oxazole, and Pyridine Derivatives as Potential Anticancer Agents Using Mixed Chalcone

New pyrazole, oxazole, and pyridine derivatives bearing naphthalene and furan moieties have been prepared by condensing 3‐(furan‐2‐yl)‐1‐(naphthalen‐2‐yl)prop‐2‐en‐1‐one 1 with different nitrogen and carbon nucleophiles such as hydrazine, hydroxylamine, cyclohexanone, cyclopentanone, ethyl cyanoacetate, and malononitrile, respectively. Cyclization of chalcone 1 with malononitrile in refluxing ethanol and ammonium acetate gave the corresponding dihydropyridine, which was condensed with different carbon electrophilic reagents such as ethyl cyanoacetate, ethyl acetoacetate, formamide, and acetic anhydride to yield the pyridine derivatives 13 – 16 . Elemental and spectroscopic evidences characterized all the newly synthesized compounds. All of the newly synthesized compounds were tested in vitro for their anti‐proliferative activities against HePG‐2 and MCF‐7 cell lines. Compounds 11 , 8 , and 15 displayed promising growth inhibitory effect toward the two cell lines compared with the standard drug doxorubicin.     

Flavonoids and biological activities of Jussiaea repens

A new acylated avicularin, namely avicularin 2'-(4'-O-n-pentanoyl)-gallate (1) along with 12 metabolites have been isolated from the ethyl acetate extract of the aerial parts of Jussiaea repens L. (Onagraceae). Their structures were established as trifolin 2'-O-gallate (2), quercetrin (3), guaijaverin (4), reynoutrin (5), juglanin (6), avicularin (7), hyperin (8), trifolin (9), hyperin 2'-O-gallate (10), rutin (11), kaempferol (12) and quercetin (13) on the basis of their chromatographic properties, chemical and spectroscopic evidences. The investigated ethyl acetate extract was found to be non-toxic (LD(50) up to the maximum soluble dose 4 g kg(-1) body wt.) and had significant antioxidant, hepatoprotective, anti-inflammatory and antidiabetic activities. Also some of the isolated flavonoids showed cytotoxic activity against Ehrlich ascitis carcinoma cells.     

Magnetic properties of nanoparticles glass–ceramic rich with copper ions

The current study aimed at the assessment of CuO gradual addition on the crystallization behavior and magnetic properties of ferromagnetic glass ceramic in the system Fe₂O₃·CaO·ZnO·SiO₂. Ferromagnetic glass–ceramics with a high quantity of magnetite were designed to be crystallized in the system Fe₂O₃·CaO·ZnO·SiO₂. The influences of gradual addition of CuO and melting temperature on the sequence of crystallization and magnetic properties were studied. The X-ray diffraction patterns showed the presence of nanometric magnetite crystals in a glassy matrix after direct cooling from the melt without any additional heat treatments. Increasing the melting temperature resulted in an increase in the magnetite crystallization. The addition of up to 20 g CuO/100 g batch composition revealed a decreasing effects in both endo- and exothermic values, whereas, the same values were inversely increased with increasing the CuO addition to 30 g. In general, increasing the CuO amounts greatly enhanced the crystallization of magnetite. A significant amount of delaffosite (CuFeO₂) was unexpectedly detected and increased by increasing both the added amount of CuO and the treatment temperature. The XRD results detected some traces of cuprite (Cu₂O) in the samples of high CuO content. The TEM results reflected the precipitation of nano-magnetite crystals in the 2–10 nm size range. Magnetic hysteresis cycles were analyzed using a vibrating sample magnetometer with a maximum applied field of 20 kOe at room temperature in quasi-static conditions. From the obtained hysteresis loops, the saturation magnetization (Ms), remanence magnetization (Mr) and coercivity (Hc) were determined.     

Antioxidant galloylated flavonol glycosides from Calliandra haematocephala

Three new acylated quercetin rhamnosides have been isolated from the leaves and stem of Calliandra haematocephala Hassk. (Fabaceae) and their structures were established as quercitrin 2'-O-caffeate (1), quercitrin 3'-O-gallate (2) and quercitrin 2',3'-di-O-gallate (3). Also, 17 known compounds were identified as gallic acid (4), methyl gallate (5), caffeic acid (6), myricitrin (7), quercitrin (8), myricetin 3-O-beta-D-4C1-glucopyranoside (9), afzelin (10), isoquercitrin (11), myricetin 3-O-(6'-O-galloyl)-beta-D-glucopyranoside (12), myricitrin 2'-O-gallate (13), quercitrin 2'-O-gallate (14), afzelin 2'-O-gallate (15), myricitrin 3'-O-gallate (16), afzelin 3'-O-gallate (17), 1,2,3,4,6-penta-O-galloyl-beta-D-4C1-glucopyranose (18), myricitrin 2',3'-di-O-gallate (19), quercetin 3-O-methyl ether (20), for the first time from the genus Calliandra except for 6. Compounds 7, 8, 13, 14, 16 and 19 exhibited moderate to strong radical scavenging properties on lipid peroxidation, hydroxyl radical, superoxide anion generation and DPPH radical in comparison with that of quercetin as a positive control in vitro. Compounds 7 and 8 exhibited lethal effect towards brine shrimp Artemia salina.     

Computing f-divergences and distances of high-dimensional probability density functions

Very often, in the course of uncertainty quantification tasks or data analysis, one has to deal with high-dimensional random variables. Here the interest is mainly to compute characterizations like the entropy, the Kullback–Leibler divergence, more general $f$-divergences, or other such characteristics based on the probability density. The density is often not available directly, and it is a computational challenge to just represent it in a numerically feasible fashion in case the dimension is even moderately large. It is an even stronger numerical challenge to then actually compute said characteristics in the high-dimensional case. In this regard it is proposed to approximate the discretized density in a compressed form, in particular by a low-rank tensor. This can alternatively be obtained from the corresponding probability characteristic function, or more general representations of the underlying random variable. The mentioned characterizations need point-wise functions like the logarithm. This normally rather trivial task becomes computationally difficult when the density is approximated in a compressed resp. low-rank tensor format, as the point values are not directly accessible. The computations become possible by considering the compressed data as an element of an associative, commutative algebra with an inner product, and using matrix algorithms to accomplish the mentioned tasks. The representation as a low-rank element of a high order tensor space allows to reduce the computational complexity and storage cost from exponential in the dimension to almost linear.