Maher El-Hashash

Antioxidant properties of methanolic extracts of the leaves of seven Egyptian Cassia species

Antioxidant properties of methanolic extracts of the leaves of seven Egyptian Cassia species In the present study, antioxidant activity of methanolic extracts of the leaves of seven Egyptian Cassia species was investigated using two methods, the phosphomolyb-date method and 1,1 diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity method.· The results revealed that C. glauca is the most potent species and that the activity of other plant species decreases in the following order: C. grandis > C. nodosa > C. fistula > C. didymobtrya > C. occidentalis > C. sophera. Defatted methanolic extract of the most active plant C. glauca was subjected to fractionation using different organic solvents such as CHCl3, EtOAc and BuOH. Antixidant activities of the fractions were investigated and the results showed that ethyl acetate fraction possessed high activity. Total phenolic and flavonoid concentrations of each plant extract were determined using the Folin-Ciocalteu reagent and aluminum chloride. Correlation between radical scavenging capacities of extracts and total phenolic concentration was observed. Antioksidativno djelovanje metanolnih ekstrakata listova sedam egipatskih vrsta roda Cassia U radu je ispitano antioksidativno djelovanje metanolnih ekstrakata listova sedam egipatskih vrsta roda Cassia koristeći fosfomolibdatnu metodu i metodu vezanja slobodnih 1,1-difenil-2-pikrilhidrazil radikala (DPPH). Rezultati pokazuju da C. glauca ima najveć u aktivnost te da se djelovanje smanjuje sljedećim redom: C. grandis > C. nodosa > C. fistula > C. didymobtrya > C. occidentalis > C. sophera. Odmašćeni metanolni ekstrakt najaktivnije biljke C. glauca frakcioniran je pomoću različitih organskih otapala kao što su CHCl3, EtOAc i BuOH. Ispitivanje antioksidativnog djelovanja pojedinih frakcija pokazuje da je etil-acetatna frakcija najaktivnija. Pomoću Folin-Ciocaltuovog reagensa i aluminijevog klorida određena je ukupna koncentracija fenola i flavonoida svakog pojedinog ekstrakta. Uočena je korelacija između sposobnosti hvatanja slobodnih radikala i ukupnog sadržaja fenola.

Synthesis and Regioselective Reaction of Some Unsymmetrical Heterocyclic Chalcone Derivatives and Spiro Heterocyclic Compounds as Antibacterial Agents

A number of novel heterocyclic chalcone derivatives can be synthesized by thermal and microwave tools. Treatment of 4-(4-Acetylamino- and/or 4-bromo-phenyl)-4-oxobut-2-enoic acids with hydrogen peroxide in alkaline medium were afforded oxirane derivatives 2. Reaction of the epoxide 2 with 2-amino-5-aryl-1,3,4-thiadiazole derivatives yielded chalcone of imidazo[2,1-b]thiadiazole derivative 4 via two thermal routes. In one pot reaction of 4-bromoacetophenone, diethyloxalate, and 2-amino-5-aryl-1,3,4-thiadiazole derivatives in MW irradiation (W 250 and T 150 °C) under eco-friendly conditions afforded an unsuitable yield of the desired chalcone 4d. The chalcone derivatives 4 were used as a key starting material to synthesize some new spiroheterocyclic compounds via Michael and aza-Michael adducts. The chalcone 4f was similar to the aryl-oxo-vinylamide derivatives for the inhibition of tyrosine kinase and cancer cell growth. The electron-withdrawing substituents, such as halogens, and 2-amino-1,3,4-thiadiazole moeity decreasing the electron density, thereby decreasing the energy of HOMO, and the presence of imidazothiadiazole moiety should improve the antibacterial activity. Thus, the newly synthesized compounds were evaluated for their anti-bacterial activity against (ATCC 25923), (ATCC 10987), (ATCC 274,) and (SM514). The structure of the newly synthesized compounds was confirmed by elemental analysis and spectroscopic data.

Phytochemical Investigation and in vitro Antioxidant Activity of Different Leaf Extracts of Salix mucronata Thunb.

The present study was aimed to determine the phytochemicals constituents of Salix mucronata Thunb. leaf extracts and their antioxidant activities. Dried leaf powders were extracted with MeOH, MeOH (85%), MeOH (70%) and distilled water. The different extracts were monitored for phytochemical screening. Total phenolic and flavonoid contents were measured by Folin-Ciocalteu and aluminum chloride assays. The antioxidant potential of tested extracts was evaluated using DPPH, ABTS and total antioxidant capacity (TAC) assays. The results showed that, MeOH (85%) extract exhibited high total phenolic and flavonoid contents (TPC=131.39±2.49 mgGAE /g ext. and TFC= 67.69±1.47 mg RE /g ext.). Also, MeOH (85%) extract showed high antioxidant activities (DPPH SC50= 98.76±0.46 (µg/ml), ABTS= 45.83±0.32 mm Trolox® eq. /100 gm extract and TAC= 199.18±2.19 mg equivalent of ascorbic acid /g ext.). On other hand, EtOAc fraction derived from MeOH (85%) extract exhibited the highest antioxidant activity; DPPH SC50= 50.19±0.24 (µg/ml), ABTS= 76.22±1.61 (mm Trolox® eq. /100 gm ext.) and TAC= 249.86±3.74 (mg equivalent of ascorbic acid /g ext.). This study demonstrated that, S. mucronata leaf is a good source of natural antioxidants. Also, there is a high correlation between the total phenolic content and the antioxidant activity.

A chemically modified electrode: decay kinetics for ferrocenes adsorbed on a carbon electrode

Abstract Electrochemical properties of immobilized ferrocene compounds on high-order pyrolytic graphite (HOPG), and first- and second-order ferricinium decay kinetics for a series of ferrocylidene cyclohexanones and acetophenones and diferrocenylphenylphosphine immobilized on HOPG are described.

Preparation and characterization of yeast cell wall beta-glucan encapsulated humic acid nanoparticles as an enhanced aflatoxin B1 binder

This study aimed to assess the effect of encapsulating humic acid inside yeast cell walls (YCW) to detoxify AFB1 in in vitro gastrointestinal models. Glucan Mannan Lipid Particles (GMLPs) from Saccharomyces cerevisiae cell walls showed the highest AFB1 adsorption in simulated gastric fluid (SGF) after 10 min, and in simulated intestinal fluid (SIF) after 1 h. GMLPs are hollow 3-4 micron porous microspheres that provide an efficient system for the synthesis and encapsulation of AFB1-absorbing nanoparticles (NPs). Humic acid nanoparticles (HA-NPs) were synthesized within the GMLP cavity by complexation with ferric chloride. Encapsulating HA-NPs in GMLPs increased HA-NP stability in SIF. The hybrid GMLP HA-NP formulation synergistically enhanced AFB1 binding compared to individual GMLP and HA components in SGF and in SIF. Cytotoxicity on a murine macrophage cell line demonstrated that GMLP HA-NP-AFB1 complexes were stable in both SGF and SIF, detoxified AFB1 and are suitable for in vivo testing.

Synthesis and anticancer activity of novel quinazolinone and benzamide derivatives

In trying to develop new anticancer agents, a series of quinazolinone and benzamide derivatives were synthesized via reaction of 6-iodo-2-phenyl-4H-benzoxazin-4-one with nitrogen nucleophiles, namely, formamide, ammonium acetate, hydrazine hydrate, hydroxylamine hydrochloride, substituted aromatic amines, benzyl amine, and/or thiocarbonohydrazide. All compounds were fully characterized by means of IR, MS, and 1H-NMR spectra. Some of the synthesized compounds were evaluated in vitro for their anti-proliferative activity against HePG-2 and MCF-7 cell lines. 2-(Benzoylamino)-N-(4-hydroxyphenyl)-5-iodobenzamide and tetrazino[1,6-c]quinazoline-3(4H)-thione derivative were the most potent against the two cancer cells comparable to that of doxorubicin. Most of the synthesized compounds also exhibited good cytotoxic activity.

Synthesis, antileishmanial and cytotoxicity activities of fused and nonfused tetrahydroquinoline derivatives

Developing novel antileishmanial, and cytotoxic drugs has been a significant area in modern pharmaceutical research. A series of novel triazolo[4,3-a]quinoline, triazino[4,3-a]quinoline, thiadiazepino[5,6-b]quinoline and pyrazolquinoline have been synthesized from the reaction of 2-hydrazinyltetrahydroquinoline-3-carbonitrile with formamide, formic acid, ethyl chloroacetate, carbon disulphide in an alcoholic solution of potassium hydroxide acetyl acetone and/or ethyl cyanoacetate, respectively. These compounds were evaluated for their in vitro studies against L. major leishmanial. The brine shrimp bioassay was also conducted to study their in vitro cytotoxic properties which displayed potent cytotoxic activity against Vincristine. The newly synthesized compounds were all characterized through IR, 1H-NMR, and MS.