El-Sayed M.E. Mahdy

Phenolic compounds from Foeniculum vulgare (Subsp. Piperitum) (Apiaceae) herb and evaluation of hepatoprotective antioxidant activity

Objective: The study was designed to evaluate the antioxidant and hepatoprotective activities of the 80% methanolic extract as well as the ethyl acetate (EtOAc) and butanol (BuOH) fractions of the wild fennel (Foeniculum vulgare (Subsp; Piperitum)) and cultivated fennel (F. vulgare var. azoricum). In addition, quantification of the total phenolic content in the 80% methanol extract of fennel wild and cultivated herbs is measured. Materials and Methods: An amount of 400 g of air dried powdered herb of wild and cultivated fennel were sonicated with aqueous methanol (80%), successively extracted with Hexane, EtOAc, and n-BuOH. The EtOAc and n-BuOH were subjected to repeated column chromatography on silica gel and Sephadex LH-20. The antioxidant effect was determined in vitro using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Hepatoprotective activity was carried out using a Wistar male rat (250–300 g). Total phenolic and flavonoid contents were determined as chlorogenic acid and rutin equivalents, respectively. Results: Two phenolic compounds, i.e., 3,4-dihydroxy-phenethylalchohol-6-O-caffeoyl-β-D-glucopyranoside and 3΄,8΄-binaringenin were isolated from the fennel wild herb, their structures were elucidated by spectral methods including 1D NMR, 2D NMR, and UV. The EtOAc and BuOH fractions of wild fennel were found to exhibit a radical scavenging activity higher than those of cultivated fennel. An in vitro method of rat hepatocytes monolayer culture was used for the investigation of hepatotoxic effects of the 80% methanol extract on the wild and cultivated fennel, which were >1000 and 1000 μg/mL, respectively. As well as, their hepatoprotective effect against the toxic effect of paracetamol (25 mM) was exerted at 12.5 μg/mL concentration. Conclusions: Fennel (F. Vulgare) is a widespread plant species commonly used as a spice and flavoring. The results obtained in this study indicated that the fennel (F. vulgare) herb is a potential source of natural antioxidant. Two phenolic compounds, i.e. 3,4-dihydroxy-phenethylalchohol-6-O-caffeoyl-β-D-glucopyranoside (A) and 3΄,8΄-binaringenin (B) were isolated from the fennel wild herb for the first time.

A New Class of Antimetabolites: Pyridine Thioglycosides as Potential Anticancer Agents

The present study was designed for highlighting and focusing on the cytotoxic activity of a new class of antimetabolites both on human cell lines, namely liver carcinoma cell line (Hepg2), lung carcinoma cell line (H460), breast carcinoma cell line (MCF7), brain carcinoma cell line (U251), and animal cell line EAC (Ehrlich ascites carcinoma cells). The results revealed that some of these modified deazapyrimidine thioglycosides have significant cytotoxic activity against EAC cells with growth inhibition percentage ranged between 80% to 90%. The possible inhibitory mechanism of the pyridine thioglycosides was explored by studying the cell cycle perturbation of thioglycosides against human cell lines (in vitro) as well as the most suitable time for maximum compound cytotoxic activity after 6, 18, and 24 h of incubation. To confirm the cytotoxic activity of these compounds, they have been tested for their apoptotic and antiproliferative activity in vivo against solid Ehrlich tumours using five groups of Swiss albino mice for 37 days from inoculation and three treatments, 250, 500 and 1,000 μg/kg body weight. There was signifi cant reduction in Ehrlich tumour size in case of the 500 and 1,000 μg/kg body weight group but mild significant tumour reduction in the 250 μg/kg body weight group. Histograms of DNA per cell for each treatment group indicated that there was a dose-dependent increase in the preG1 phase with a corresponding complete arrest of cells from entering the G2/M phase compared to the untreated EAC group. In conclusion, pyridine thioglycosides have proven good cytotoxic effects against EAC cells and also significant cytotoxic activity against the four tested human cell lines. Flow cytometric DNA ploidy analysis of pyridine thioglcyosides against the Hepg2 and U251 cell lines revealed that the postulated mechanism of action of pyridine thioglcyosides is cell cycle arrest in the S phase. This is similar to antimetabolites and cell cycle arrest in the G2/M phase (M phase) in the same way as microtubule inhibitors like pyridine thioglycosides are cell-cycle-specific in the S phase and the M phase (in case of human cell lines) and have apoptotic effects (in case of animal cell line).

Fish oil omega-3 fatty acids reduce the severity of radiation-induced oxidative stress in the rat brain

Abstract Purpose: To evaluate the modulator role of fish oil (FO) on some biochemical changes in the brain of gamma-irradiated rats (RAD). Material and methods: Male albino rats Sprague Dawley were divided into four groups (n = 10). (i) Control: received vehicle via gavages during 28 days; (ii) FO: received fish oil (400 mg/kg/day) via gavages during 28 days; (iii) RAD: received vehicle for 7 days before whole body gamma-irradiation with 8 Gy given in four fractions each 7 days apart and continued during the irradiation period; and (iv) FO+ RAD: received FO for 7 days before exposure to the first dose of irradiation and FO treatment was continued during the irradiation period. Animals were sacrificed 24 hours post the last irradiation dose. Results: A significant increase of malondialdehyde (MDA) and protein carbonyl (CO) content associated with a significant decrease of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities and glutathione (GSH) content were recorded in the brain of irradiated rats. Oxidative stress was accompanied by a significant decrease of eicosapentaenoic (EPA) and docosahexaenoic (DHA) levels. Aspartic (Asp) and glutamic (Glu) acid levels were increased. Serotonin level showed a decrease associated with enhanced monoamine oxidase (MAO) activity and increased 5-hydroxyindolacetic acid (5-HIAA) level. FO treatment reduced the severity of radiation-induced oxidative stress, alteration of Asp and Glu levels and serotonin metabolism concomitant with increased EPA and DHA levels. Conclusion: FO attenuates the severity of radiation-induced biochemical disorders in the brain by counteracting the radiation-induced decrease of EPA and DHA. Further studies are needed concerning the long-term implications of our findings.

The activity of detoxifying enzymes in the infective juveniles of Heterorhabditis bacteriophora strains: Purification and characterization of two acetylcholinesterases

The infectivity and detoxifying enzyme activities including glutathione-S-transferase (GST), acetylcholinesterase (AChE) and carboxylesterase (CaE) are investigated in the infective juveniles (IJs) of six different strains of Heterorhabditis bacteriophora as a biocontrol agent against insect pests. The specific activities ranged from 10.8-29.8 and 50-220units/mg protein for GST and AChE, respectively; and from 24.7-129 and 22.6-77.3units/mg protein for CaE as estimated by P-nitrophenyl and α-naphthyl acetates, respectively. H. bacteriophora EM2 strain has the highest infectivity and the highest enzymatic activities as well. AChE is the predominant detoxifying enzyme that might imply its major role in the detoxification of insecticide(s). The isoenzyme pattern demonstrated two major slow-moving isoforms in all EPN strains examined. Purification of two AChE isoforms, AChEAII and AChEBI, from H. bacteriophora EM2 strain is performed by ammonium sulfate precipitation, gel filtration on Sephacryl S-200 and chromatography on DEAE-Sepharose. AChEAII and AChEBII have specific activities of 1207 and 1560unit/mg protein, native molecular weights of 180 and 68kDa, and are found in dimeric and monomeric forms, respectively. Both isoforms showed optimum activity at pH8.5 and 35°C. AChEBI exhibited higher thermal stability and higher activation energy than AChEAII. The enzymatic activities of purified AChEs are completely inhibited by Hg(+2) and Ni(+2) and greatly enhanced by Mn(+2). The substrate specificity, the relative efficiency of substrates hydrolysis, substrate inhibition and inhibition by BW284C51, but not by iso-OMPA, clearly indicated that they are true AChEs; their properties are compared with those recorded for insects as target hosts for H. bacteriophora EM2.

Acetylcholinesterases from entomopathogenic nematode Heterorhabditid bacteriophora: Susceptibility to insecticides and immunological characteristics

Acetylcholinesterases (AChEs) from the infective juveniles (IJs) of entomopathogenic nematode (EPN) have been investigated with respect to their susceptibility to insecticides and immunological characteristics, aiming at nominating the most compatible insecticide(s) to be used in conjunction with the most insecticide-tolerant EPN strain before incorporation in integrated pest management (IPM) programs. The inhibition kinetics of two purified AChE isoenzymes, AChEAII and AChEBI isolated from Heterorhabditid bacteriophora EM2 strain, by different insecticides revealed that the insensitivity to inhibition by such insecticides could be arranged in a descending order as; methomyl>carbofuran>acetamiprid>oxamyl>malathion. Except for malathion, the insecticides competitively inhibited AChEs with Ki values ranging from 0.1 to 15mM and IC50 values from 1.25 to 23mM. The two AChE isoforms are several folds less sensitive to inhibition by methomyl and carbofuran compared to those previously reported for other insect species. AChEBI was used as an immunogen to raise anti-AChEBI antisera in rabbits. The prepared antisera cross-reacted with AChEs of five different heterorhabditid nematode strains implying the presence of common epitopes shared along all the examined strains. Such studies could aid in the rational selection of the compatible insecticide(s) and the prepared polyclonal anti-AChE antisera would be a valuable immunodiagnostic tool for evaluating the most insecticide-tolerant EPN strain(s) in IPM programs.