Nahla Ayoub

Ain Shams University, Al Qāhirah, Al Qāhirah, Egypt

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Publications (20)32.07 Total impact

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    ABSTRACT: Epidemiological studies have proven an association between consumption of polyphenols and prevention of Alzheimer's disease, the most common form of dementia characterized by extracellular deposition of amyloid beta plaques. The aim of this study is pharmacological screening of the aqueous alcohol extract of Markhamia platycalyx leaves, Schotia brachypetala leaves and stalks, and piceatannol compared to aqueous alcohol extract of Camellia sinensis leaves as potential Alzheimer's disease drugs. LC-HRESI(-ve)-MS(n) was performed to identify phenolics' profile of Schotia brachypetala stalks aqueous alcohol extract and revealed ten phenolic compounds as first report: daidzein, naringin, procyanidin isomers, procyanidin dimer gallate, quercetin 3-O-rhamnoside, quercetin 3-O-glucuronide, quercetin hexose gallic acid, quercetin hexose protocatechuic acid, and ellagic acid. Alzheimer's disease was induced by a single intraperitoneal injection of LPS. Adult male Swiss albino mice were divided into groups of 8-10 mice each receiving treatment for six days. In vivo behavioral tests (Y maze and object recognition) and in vitro estimation of amyloid beta 42 by ELISA showed significant differences between results of treated and nontreated animals.
    BioMed Research International 01/2014; 2014:843263. · 2.71 Impact Factor
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    ABSTRACT: The anti-inflammatory effect of two main components in the aqueous ethanol extract of both Corchorus olitorius (Co) and Vitis vinifera (Vv), namely quercetin 3-O-β-D-4C1 galactoside and quercetin 3-O-β-D-4C1 glucuronide, respectively, were investigated. The major components were isolated and their structures elucidated. It was observed that the two extracts decreased carrageenan-induced rat paw oedema in inflammatory exudates with histopathological changes, decreased density of TNF-α immunoreactive cells, inhibited vascular permeability induced by acetic acid and increased nitric oxide production in the rat air pouch. Biochemical assays showed that extracts of both plants restored reduced glutathione level and increased superoxide dismutase activity and both were active against COX-I and COX-II enzymes inhibition. The isolated compounds inhibited COX-I and had doubled inhibition percentage effect on COX-II enzymes, as confirmed by in silico docking studies. These extracts also showed activity against metastatic melanoma, leukemia and osteosarcoma cell lines.
    Journal of Functional Foods 07/2013; 5(3):1204-1216. · 2.63 Impact Factor
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    ABSTRACT: The volatile constituents of the oil from the leaves of Ficus carica Linn. (Moraceae), isolated by hydrodistillation,were analysed by GC and GC-MS. The leaf oil was found to contain 66 compounds, of which 44 compounds were identified. The oil was rich in oxygenated compounds of different classes, (Z)-3-hexenyl benzoate (19.8 %) was the most abundant. The other major components were n-Tetracosane (11.6 %), n-hexadecanoic acid (9.2 %), n-Docosane (7.7 %), (E)-2-hexenal (7.2 %), phytol (6.7 %) and n-nonanal (3.9 %).
    Journal of essential oil-bearing plants JEOP 03/2013; 13(3):316-321. · 0.29 Impact Factor
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    ABSTRACT: Cuphea hyssopifolia Kunth (Family Lythraceae) is a herb, newly cultivated in Egypt. Its richness in phenolics had led to test for its antioxidant and cytotoxic activities and isolation of its componenets. Also it urges us to check for its genotyping. Isolation of some phenolics was done using usual chromatographic techniques. The genetic fingerprinting of the aerial parts of C. hyssopifolia Kunth was determined using RAPD-PCR (Random Amplified Polymorphic DNA) technique which has been widely used in plants for the construction of genetic maps using 10 primers. The antioxidant activity of the extract was measured using the stable free radical DPPH assay while its cytoctoxic property was tested using different cell lines viz MCF7 (breast carcinoma cell line), HEP2 (larynx carcinoma cell line), HCT116 (colon carcinoma cell line) and HEPG2 (liver carcinoma cell line) adopting SRB method. Several compounds had been isolated from the aqueous methanolic extract of the aerial parts of C. hyssopifolia Kunth namely valoneic acid dilactone (1), 1,3−O−digalloyl-4-,6-hexahydroxydiphenoyl-β-D− 4 C 1 -glucopyarnose (2), gallic acid (3), genistein-7-O-β-D-4 C 1 -glucopyranoside (4), myricetin−3 − O− β-D− 4 C 1 -glucopyarnoside (5), 3, 4, 5-trimethoxy benzoic acid (6), vanilic acid (7) and quercetin (8). Primer OPP-01 was the best sequence for dominating C. hyssopifolia Kunth cultivated in Egypt. The antioxidant activity of the extract showed an inhibition 95.5% compared to that of ascorbic acid 98.35%. The extract showed moderate cytotoxic activity with IC 50 ranging from 73.4 to 92.5 ug/ml for the tested cell lines. The study suggests that C. hyssopifolia Kunth may be the potential rich source of natural antioxidant. INTRODUCTION: Cuphea hyssopifolia Kunth (Lythraceae), a small shrub native to Mexico and Guatemala, is cultivated in Egypt as a horticultural plant [1].
    Journal of Pharmacognosy and Phytochemistry. 11/2012; 1(4):68-78.
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    ABSTRACT: An HPLC–PDA–ESI/MS/MS method was developed to identify the phytoconstituents of the EtOAc fraction of Eucalyptus gomphocephala DC. The antioxidant effect of the EtOAc fraction together with its sub-fractions was determined in vitro. The cytotoxicity was evaluated on different cell lines. The EtOAc fraction exhibited strong antioxidant activity, reduced the viability of all cell lines and was more active on MCF-7 and HepG-2 cell lines. Subsequently, the cytotoxicity of the sub-fractions and the isolated compounds were tested on MCF-7, HepG-2. The EtOAc fraction possessed potential antitumour promoting properties. It inhibited the stimulated NO (20%), 5-LOX (48.0%) and COX-2 (49.7%) respectively (at concentration of 20μg/ml). This study suggests that this fraction is a source of different antioxidant and cytotoxic compounds with potential chemopreventive properties that might prevent different stages of the carcinogenesis process.
    Food Chemistry 08/2012; · 3.33 Impact Factor
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    ABSTRACT: Three ellagitannins and one disulfated flavonol were isolated from the aerial parts of Reaumuria vermiculata L. Besides that, 16 known compounds were characterized as well. The structures of all compounds were elucidated on the basis of spectroscopic data including 1D and 2D NMR and ESI HR-FTMS. The in vivo antioxidant activity using the oxygen radical absorbance capacity (ORAC) method, of the extract, its column fractions and two of the isolated ellagitannins was accomplished. In addition, a possible cytotoxicity of the extract and two of the new ellagitannins on HaCaT human keratinocytes and the activity of both compounds against the prostate cancer cell line (PC-3) were also assessed, whereby a potent cytotoxicity with IC₅₀ less than 1 μg/ml was determined for both compounds. Besides, the extract exhibited a potential cytotoxic effect against four different solid tumor cell lines, namely liver (Huh-7), colorectal (HCT-116), breast (MCF-7) and prostate (PC-3). The IC₅₀s were found to be substantially low (ranged from 1.3±0.15 to 2.4±0.22 μg/ml) with relatively low resistance possibility reaching to 0% in the case of Huh-7 cell.
    Fitoterapia 06/2012; 83(7):1256-66. · 2.23 Impact Factor
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    ABSTRACT: Chemical investigation on leaves of Annona muricata resulted in the isolation of the flavonol triglycoside, quercetin 3-O-α-rhamnosyl-(1″″ → 6″)-β-sophoroside, together with twelve known phenolics. The structures of these compounds were established by 1D- and 2D-nuclear magnetic resonance spectroscopic techniques and mass spectrometry data. The in vitro antioxidant studies of the investigated aqueous ethanol extract and its column fractions were accomplished using the oxygen radical absorbance capacity (ORAC) method. A stimulating effect on HaCaT human keratinocytes by the leaf extract was also assessed. Il-6 production after UV irradiation was not influenced by A. muricata leaf extract.
    Archives of Pharmacal Research 05/2012; 35(5):761-7. · 1.54 Impact Factor
  • Food Chemistry 01/2012; 133(3):1017–1024. · 3.33 Impact Factor
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    ABSTRACT: Assessment of the UV protecting potential of an aqueous methanol leaf extract of Harpephyllum caffrum proved that it possesses a distinct radical scavenging effect and inhibits the production of the proinflammatory cytokine IL-6 by human keratinocytes (HaCaT cells) following UV radiation. Phytochemical investigation of this extract led to isolation and structural determination of the hitherto unknown phenolics, kaempferol 3-O-(2″-sulphatogalactopyranoside), its quercetin analogue and 3-methoxyellagic acid 4-O-galactopyranoside in addition to 18 known phenolic compounds. The structures were determined by spectroscopic and conventional methods of analysis. Flavonoid sulphatoglycosides which have been rarely found in nature were major phenolic constituents of this plant, and this is the first report of the isolation of any of them from Anacardiaceae. The extract was found to diminish UV phototoxic reaction of keratinocytes. However, the isolated kaempferol sulphatogalactopyranoside did not interact with UVB triggered IL-6 production of HaCaT keratinocytes.
    Fitoterapia 08/2011; 82(8):1265-71. · 2.23 Impact Factor
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    ABSTRACT: A wide range of phytochemical constituents have been reported from genus Cuphea are tannins , flavonoids, triterpenes, sterols, aromatic acids, carbohydrates, unsaturated fatty acids and alkanes. This genus is biologically studied for cytotoxic activities, antiviral activities, antimicrobial activities, anti-Helicobacter pylori activities, antiprotozoal activities, cardiovascular activities, antioxidant activities and anti-diuretic activities. It has been evaluated for the cytological parameters, reduction of plasma cholesterol and losing weight.
    Research Journal of Pharmaceutical, Biological and Chemical Sciences,www.rjpbcs.com,. 07/2011; 2(3):847-855.
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    Records of Natural Products 01/2011; 5(4):271–280. · 1.56 Impact Factor
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    ABSTRACT: The inhibitory glycine receptor (GlyR) is a key mediator of synaptic signaling in spinal cord, brain stem, and higher central nervous system regions. The flavonoids quercetin and genistein have been identified previously as promising GlyR antagonists in vitro, but their detailed mechanism of action was not known. Here, inhibition of recombinant human α1 GlyRs in HEK 293 cells by genistein, quercetin, and strychnine was studied using whole-cell recording techniques. The interaction of several inhibitors applied alone or in combination was analyzed using a minimum mechanism of receptor activation and inhibition. Receptor inhibition in vivo was studied in a mouse model of strychnine toxicity. Genistein, quercetin, and strychnine were noncompetitive GlyR inhibitors. The inhibitory potency of one flavonoid (either genistein or quercetin) was not affected by simultaneous application of the other, suggesting that both flavonoids target the same site on the receptor. In combination with strychnine, flavonoid inhibition was augmented, indicating that strychnine binds to a position on the receptor physically distant from the flavonoid site. Potentiation of strychnine inhibition by flavonoids was also observed in vivo, where harmless doses of flavonoids enhanced strychnine toxicity in mice. Thus, in vitro and in vivo studies demonstrated a true synergism between flavonoids and strychnine for GlyR inhibition. The mechanism-based approach used here allows a rapid analysis of the effects of single drugs versus drug combinations.
    Toxicological Sciences 11/2010; 118(1):171-82. · 4.33 Impact Factor
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    ABSTRACT: 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.
    Natural product communications 10/2010; 5(10):1639-42. · 0.96 Impact Factor
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    ABSTRACT: Evaluation of the activity of an aqueous alcoholic extract obtained from the leaves of Heimia myrtifolia (Lythraceae) by determining its stimulating effect on two human osteoblastic cell lines HOS58 and SaOS-2 indicated its potential for use in the prevention and treatment of osteoporosis. In addition, the extract was found to significantly increase the mineralization of cultivated human bone cell SaOS-2, in which a strong dose-dependent increase was observed. A phytochemical investigation of the extract also confirmed that H. myrtifolia is capable of synthesizing and accumulating appreciable amounts of several phenolics, thus leading to the isolation and characterization of sixteen of these constituents. Identified among these isolates were a new natural product, 1,6-di-O-dehydrotrigalloyl-β-D-(4)C(1)-glucopyranose, and a rare natural product (this marks its second report), 5,7,4'-trihydroxy-3-methoxyflavanone (dihydrokaempferol-3-O-methyl ether). Structures of these isolates were fully elucidated on the basis of conventional methods of analysis and confirmed by ESI/MS and (1)H and (13)C-NMR analysis.
    Drug discoveries & therapeutics. 10/2010; 4(5):341-8.
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    ABSTRACT: This review presents an overview of azaphilones isolated from different species of fungi, detailing their chemical structures and biological activities as covered in the recent literature. Over 170 different azaphilone compounds occur in fungi belonging to 23 genera from 13 families: these azaphilones can be classified into ten different structural groups. Numerous azaphilone structures have been described, particularly from members of the Trichocomaceae and Xylariaceae families. Azaphilones exhibit a wide range of interesting biological activities, such as antimicrobial, antifungal, antiviral, antioxidant, cytotoxic, nematicidal and anti-inflammatory activities. Many of these effects may be explained by the reactions of azaphilones with amino groups, such as those found in amino acids, proteins and nucleic acids, resulting in the formation of vinylogous γ-pyridones. KeywordsAzaphilones-Bioactivity-Lactones- Trichocomaceae - Xylariaceae
    Phytochemistry Reviews 06/2010; 9(2):315-342. · 4.15 Impact Factor
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    ABSTRACT: A liquid chromatography-diode array detection-electrospray ionization mass spectrometric (HPLC-PDA-ESI/MS/MS) method was used for the analysis of the phenolic composition of the ethanolic extract obtained from the leaves of Pleiogynium timorense (DC.) Leenh. Twenty compounds were detected and tentatively characterized. In addition, further phytochemical investigations of the extract resulted in the isolation of twelve major phenolic compounds. Evidence of the structures of these compounds was obtained based on the interpretation of the UV, 1H NMR, 13C NMR and DQF-COSY spectral data. The antioxidant effect of the ethanolic extract was examined in vitro using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and super oxide anion radical scavenging assays. DPPH radical scavenging activity was observed for the extract, with an IC50 of 21.9 microg/mL, while its super oxide anion scavenging activity was less pronounced, with an IC50 of 123.5 microg/mL The ethanolic extract showed significant hypoglycemic, antioxidant and anti-inflammatory properties. This study suggests that the ethanolic extract of Pleiogynium timorense is a potential source of antioxidant compounds, relatively non-toxic, and have possible beneficial health effects.
    Natural product communications 04/2010; 5(4):545-50. · 0.96 Impact Factor
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    ABSTRACT: Due to our interest in bioactive plant derived materials, the hepatoprotective activity of the aqueous alcoholic extract of Gentiana spicata AEGS (Gentianaceae) on carbon tetrachloride treated rats was investigated. CCl4 used at a concentration of 1 mL/kg.b.wt. significantly increased the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). However, pre-treatment with AEGS and its individual components significantly prevented the increase in these enzymes, which are the major indicators of liver injury. Biochemical assays of liver homogenate showed that AEGS and its components restored reduced glutathione (GSH) depletion reduced the level of thiobarbituric acid reactive substances (TBARS). Furthermore, liver histological observation also showed an obvious amelioration in liver cell necrosis, liver lesions, and fatty changes in pre-treated groups. Phytochemical investigation of the extract showed high phenolic content and led to the isolation and identification of the new carboxygentisic acid, 1,4-dicarboxy 2,5-dihydroxybenzene, for which we suggest the name spicatic acid, together with the known flavonoids, quercetin 3-O-[(2,3,4-triacetyl-α-rhamnopyranosyl)1'''→6''] 3-acetyl-β-galactopyranoside and quercetin 3-O-[(2,3,4-triacetyl-α-rhamnopyranosyl)1'''→6'']-4-acetyl-β-galactopyranoside, epicatechin, catechin and their gallolyated derivatives. All structures were elucidated on the basis of conventional analytical methods and confirmed by high resolution ESIMS, 1D- and 2D-NMR data. The new phenolic 4-carboxygentisic acid, spicatic acid is of special interest as it represents the first phenolic acid in nature which bears two carboxyl functions in one aromatic ring.
    Drug discoveries & therapeutics. 12/2009; 3(6):278-86.
  • Nahla Ayoub, Dennis Lass, Wulf Schultze
    International Journal of Medicinal Mushrooms - INT J MED MUSHROOMS. 01/2009; 11(1):55-60.
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    ABSTRACT: The essential oils of Eryngium yuccifolium Michaux. (Apiaceae) were isolated from the leaves, stalks and roots by hydrodistillation. Analysis of the oils by GC and GC–MS revealed that the leaves oil contained 49 compounds, of which germacrene D (18.3%), terpinolene (17.8%), bicyclogermacrene (8.8%), -pinene (7.6%), ß-caryophyllene (6.2%) and falcarinol (9.6%) were found to be the major constituents. In addition, 40 compounds were identified from the stalk oil, among which, germacrene D (38.4%), -amorphene (12.2%), bicyclogermacrene (10.1%), bicyclosesquiphellandrene (3.4%) and falcarinol (3.2%) were the major components. The roots oil was found to contain 25 compounds, of which, terpinolene (25.8%), trans-β-bergamotene (18.6%) and the benzaldehyde 2,3,6-trimethylbenzaldehyde (13.9%), were the major constituents. Yuccifolol (nonadeca-1,11-diene-4,6,8-triyne-3,10-diol), a novel polyacetylene, was isolated and identified from the hexane:ether extract of the aerial parts, together with the known polyacetylenes, falcarinone [heptadeca-1,9-(Z)-dien-4,6-diyn-3-one], falcarinol (heptadeca-1,9-dien-4,6-diyn-3-ol) and heptadeca-1,8-diene-4,6-diyne-3,9-diol. The chemical structures of these constituents were established by NMR (DEPT, COSY, HMQC and HMBC) as well as HRESI–MS analysis. Copyright © 2006 John Wiley & Sons, Ltd.
    Flavour and Fragrance Journal 07/2006; 21(6):864 - 868. · 1.82 Impact Factor
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    ABSTRACT: Cineole(82.6%), α-Terpineol (4.93%), globulol(1.73%) and α-pinene (0.99%) were found to be the major constituents of the essential oil from E. cineria grown in Egypt while, analysis of the essential oil from the same tree grown in the northwest Himalayas of India contained cineole(64.65%), α-Terpineol(11.56%), and limonene(12.51%) as the major components(2). Differences in concentrations were attributed to climatic variations. In addition to Cineole(78.3%), other major constituents of the essential oil from C. viminalis included: linalol(5.16%), α-Terpineol (4.21%), Myrcene(1.67%), β-pinene(1.30), and α-pinene(0.50%). Similar major components and concentrations were recorded for the same species growing in Australia (3). In case of C. quadrifidus, this is considered the first report regarding GC/MS analysis of its essential oil.The results show similar major components to that of C. viminalis; with Cineole(80%), β-pinene(3.79), α-pinene(2.34), linalool(0.14), and α-Terpineol(0.99). The antimicrobial study for the three oils revealed very similar results which is expected due to the close resemblance of their oil components. Results are compiled in table (2). The oils also inhibited the growth of Mycobacterium tuberculosis inoculated in lowenstein- Jensen medium.