Determination of the polyphenolic content of a Capsicum annuum L. extract by liquid chromatography coupled to photodiode array and mass spectrometry detection and evaluation of its biological activity

The present study was aimed to investigate the polyphenolic profile of a pepper (Capsicum annuum L.) extract from Algeria and evaluate its biological activity. The total polyphenol content of the extract was determined as 1.373 mg of gallic acid equivalents (±0.0046), whereas the flavonoids were determined as 0.098 mg of quercetin (±0.0015). The determination of the complete polyphenolic profile of the extract was achieved by liquid chromatography with an RP‐amide column in combination with photodiode array and mass spectrometry detection through an electrospray ionization interface. A total of 18 compounds were identified, of which five were reported for the first time in the sample tested. Quercetin rhamnoside was the most abundant compound (82.6 μg/g of fresh pepper) followed by quercetin glucoside (19.86 μg/g). The antioxidant activity and antimicrobial effects were also determined. For the antimicrobial tests assessed against Gram‐positive and Gram‐negative bacteria, kaempferol showed the strongest inhibitory effect followed by quercetin and caffeic acids. In the study of the cytotoxicity of the extract, the cancer cells (U937) were more affected than the normal cells (peripheral blood mononucleated cells), with more than 62% inhibition at the highest concentration.     

On the singular limit of a model transport semigroup

We consider the diffusion limit of a model transport equation on the torus or the whole space, as a scaling parameter ε (the mean free path), tends to zero. We show that, for arbitrary initial data $u_0(x,v)$\nopagenumbers\end , the solution converges in norm topology for each $t>0$\nopagenumbers\end , to the solution of a diffusion equation with initial data \def\d{{\rm d}}$u_D^0(x)=\int u_0(x,v)\,\d v$\nopagenumbers\end . The proof relies on Fourier analysis which diagonalizes the transport operator, a Dunford functional calculus and the analysis of the behaviour of the transport spectrum as ε tends to zero. Copyright © 2000 John Wiley & Sons, Ltd.     

Haematococcus pluvialis as a Potential Source of Astaxanthin with Diverse Applications in Industrial Sectors: Current Research and Future Directions

Haematococcus pluvialis, a green microalga, appears to be a rich source of valuable bioactive compounds, such as astaxanthin, carotenoids, proteins, lutein, and fatty acids (FAs). Astaxanthin has a variety of health benefits and is used in the nutraceutical and pharmaceutical industries. Astaxanthin, for example, preserves the redox state and functional integrity of mitochondria and shows advantages despite a low dietary intake. Because of its antioxidant capacity, astaxanthin has recently piqued the interest of researchers due to its potential pharmacological effects, which include anti-diabetic, anti-inflammatory, and antioxidant activities, as well as neuro-, cardiovascular-, ocular, and skin-protective properties. Astaxanthin is a popular nutritional ingredient and a significant component in animal and aquaculture feed. Extensive studies over the last two decades have established the mechanism by which persistent oxidative stress leads to chronic inflammation, which then mediates the majority of serious diseases. This mini-review provides an overview of contemporary research that makes use of the astaxanthin pigment. This mini-review provides insight into the potential of H. pluvialis as a potent antioxidant in the industry, as well as the broad range of applications for astaxanthin molecules as a potent antioxidant in the industrial sector.     

含偶氮苯与噻吩结构单元的共轭聚合物合成及酸致变色性质

以1,3-二(二苯膦基)丙烷二氯化镍(Ⅱ)作催化剂[Ni(dpp)Cl2],通过2,5-二溴噻吩格式试剂与4,4′-二碘偶氮苯共聚得到了一种新型共轭聚合物.采用红外光谱、核磁共振氢谱对聚合物的结构进行表征并通过紫外-可见吸收光谱、荧光光谱、X-射线衍射、热失重分析(TGA)、差热分析(DTA)等测试手段对聚合物的性能进行了详细的研究.紫外可见光谱分析结果表明,聚合物在384 nm处显示了偶氮苯发色团的特征吸收峰,相对于单体红移34 nm.在聚合物的氯仿溶液中观察到酸致变色现象,即分别加入CF3COOH和CH3SO3H后,溶液颜色由黄色分别变成墨绿色和紫色,而加入三乙胺溶液后溶液恢复到初始颜色.在25℃下测得的特性粘数为0.53 dL/g.热失重分析结果显示,该聚合物具有较好的热稳定性.     

Speciation of manganese in fresh water-I Use of EPR studies

The process of standardization of the use of electron paramagnetic resonance (EPR) spectrometry in the determination of Mn(II) species in aqueous solution by comparison with atomic absorption spectrometry (AAS) is discussed. It is shown that EPR signals obtained from standardized aqueous solutions of manganese(II) perchlorate and nitrate in the concentration range of 0.05-2 mg/l. do not vary significantly over the pH range 2.1-7.0. Study of the effect (on the manganese EPR signals) of the addition of inorganic ions commonly found in significant concentrations in natural waters, viz. chloride, sulphate and bicarbonate, has shown that such ions, at the levels reported to occur in surface fresh waters, will not complex manganese(II); however, evidence is obtained that humic acid/manganese complexes could be present in such waters. The EPR signals are not affected by ionic strengths of the levels found in fresh waters.     

Potential Anticancer Activity of the Furanocoumarin Derivative Xanthotoxin Isolated from Ammi majus L. Fruits: In Vitro and In Silico Studies

Ammi majus L., an indigenous plant in Egypt, is widely used in traditional medicine due to its various pharmacological properties. We aimed to evaluate the anticancer properties of Ammi majus fruit methanol extract (AME) against liver cancer and to elucidate the active compound(s) and their mechanisms of action. Three fractions from AME (Hexane, CH₂Cl₂, and EtOAc) were tested for their anticancer activities against HepG2 cell line in vitro (cytotoxicity assay, cell cycle analysis, annexin V-FITC apoptosis assay, and autophagy efflux assay) and in silico (molecular docking). Among the AME fractions, CH₂Cl₂ fraction revealed the most potent cytotoxic activity. The structures of compounds isolated from the CH₂Cl₂ fraction were elucidated using ¹H- and ¹³C-NMR and found that Compound 1 (xanthotoxin) has the strongest cytotoxic activity against HepG2 cells (IC₅₀ 6.9 ± 1.07 µg/mL). Treating HepG2 cells with 6.9 µg/mL of xanthotoxin induced significant changes in the DNA-cell cycle (increases in apoptotic pre-G1 and G2/M phases and a decrease in the S-phase). Xanthotoxin induced significant increase in Annexin-V-positive HepG2 cells both at the early and late stages of apoptosis, as well as a significant decrease in autophagic flux in cancer compared with control cells. In silico analysis of xanthotoxin against the DNA-relaxing enzyme topoisomease II (PDB code: 3QX3) revealed strong interaction with the key amino acid Asp479 in a similar fashion to that of the co-crystallized inhibitor (etoposide), implying that xanthotoxin has a potential of a broad-spectrum anticancer activity. Our results indicate that xanthotoxin exhibits anticancer effects with good biocompatibility toward normal human cells. Further studies are needed to optimize its antitumor efficacy, toxicity, solubility, and pharmacokinetics.     

Syntheses of novel 1,5-benzodiazepine derivatives: Crystal structures,spectroscopic characterizations,Hirshfeld surface analyses,molecular docking studies,DFT calculations,corrosion inhibition anticipation,and antibacterial activities

A series of newly pyrazolo-1,5-benzodiazepine derivatives ( 5 - 7 ) was performed and characterized by using ¹H, ¹³C-NMR spectroscopic measurements. The molecular and crystal structures of two compounds 2 and 7 have also been further examined by single-crystal X-ray crystallography showing that the alkyl groups are beard by sulfur atom and to pyrazolic nitrogen atom in position 2 and not in position 1 of the tricyclic compounds as described in the literature. In addition, through Hirshfeld surface analysis, molecular docking studies, and DFT calculations, the closest contact between the active atoms of the compound can be determined. Also, the Monte Carlo simulations outcomes show that compounds 2 and 7 can be considered as a good acidic corrosion inhibitor for the aluminum metal, while emphasizing that the compound 7 provides enhanced prevention. Finally, compounds 1 to 7 were evaluated for their antibacterial activity against Gram-positive and Gram-negative microbial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus. The results obtained demonstrated the antibacterial activity of compounds 1 to 7 tested using the minimal inhibitory concentration.     

Efficient Entrapment of Oxirane Ring Containing Compounds in Thermally Stable Poly(urea-formaldehyde) Polymer Shell Wall

This article aims to address the problems associated with the encapsulation of oxirane ring containing compounds in poly(urea-formaldehyde) (PUF) shell for application in self-healing composite systems. The main objectives were to produce non-agglomerated, stable microcapsules, and to control the pH drop during the encapsulation via oil-in-water emulsion polymerization. In the modified method; two stage additions of urea and formaldehyde monomers, core to shell ratio, weight percent and combination of two surfactants/emulsifiers were altered to produce the desired product. Analysis was done with optical microscope (OM), scanning electron microscopy (SEM), FTIR, particle size analyzer, and thermogravimetric analysis (TGA). The pH drop was confirmed by using a common epoxy resin, an epoxy functionalized polydimethylsiloxane (E-PDMS), and epoxidized palm oil (EPO) as cores. The modified oil-in-water emulsion polymerization of PUF was effective in preventing the pH drop during the encapsulation and a product stable for more than 3 months with less agglomeration was produced. The method produced microcapsules having diameters less than 100 μm at lower agitation rates. The modified method is only applicable to epoxy resin and not for compounds like amine hardeners. The use of stable microcapsules in self-healing coatings can lead towards cost reduction implied for repair and maintenance purposes.