Ahmed H Gaara

Jazan University, Djayzān, Jizan, Saudi Arabia

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Publications (6)2.48 Total impact

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    ABSTRACT: 10 polyphenols were identified from 80% aqueous methanol extract (AME) of Markhamia platycalyx [(Baker) Sprague] leaf. Their structures were characterized as protocatechuic acid (1), E-caffeic acid (2), E-methyl caffeate (3), isoverbascoside (4), verbascoside (5), jacraninoside-I (6), cosmosiin (7), cinaroside (8), luteolin (9) and apigenin (10) based on chemical and extensive spectral studies (UV, ESI-MS, 1H, 13C and 1D/2D NMR). Biological evaluation indicated that AME is non-toxic to the experimental animals. It exhibited a significant inhibition of oedema after 1, 2, 3 and 4 h for all examined doses (250, 500 and 1 000 mg/kg). In comparison with silymarin, the AME demonstrated a significant hepatoprotective effect in the form of high reduction in elevated ALT and AST serum levels in regard to paracetamol treated group. As well as, it revealed a marked significant scavenging activity by 62.9, 82.5, 88.3, 83.7 and 83.7%, for the concentrations 20, 40, 60, 80 and 100 mg/ml of the extract, respectively, relative to L-ascorbic acid (86.8%), which was used as a reference antioxidant drug.
    No preview · Article · Apr 2014
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    ABSTRACT: Albizia species are rich in phenolics and terpenes in the different plant organs. They are widely used in traditional Chinese medicine. So this study investigated the phytochemical and biological activities of Albizia Anthelmintica. Column chromatography has been performed for the isolation of compounds. Bioactivity studies of A. anthelmintica leaves were carried out on aqueous ethanol extract and some pure compounds were tested for their antioxidant activities. Eight compounds have been isolated for the first time from A. anthelmintica. The aqueous ethanol extract of A. anthelmintica showed moderate anti-inflammatory activity and significant for both analgesic and antioxidant activities. Quercetin-3-O-β-D-glucopyranoside, kaempferol-3-O-β-D-glucopyranoside, kaempferol-3-O-(6β-O-galloyl-β-D-glucopyranoside and quercetin-3-O-(6β-O-galloyl-β-D-glucopyranoside) exhibited potent antioxidant scavenging activity towards diphenyl-picrylhydrazine.
    Full-text · Article · Apr 2013
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    ABSTRACT: Objectives The aim of this study was to investigate a new flavone triglycoside, together with eleven phenolic metabolites from 80% aqueous methanol extract of S. splendens leaves (AME) and assessment of its hypoglycemic and antiinflammatory activities along with in vitro antioxidant effect. Methods The phenolic composition of S. splendens leaves was analyzed using UV, 1D and 2D NMR and negative ESI-MS spectroscopy. Hypoglycemic activity of AME was assessed by measuring blood glucose in streptozotocin induced-diabetic rats. Antiinflammatory activity was evaluated using the carrageenan-induced paw oedema test. Antioxidant activity was evaluated in vitro using DPPH test. Key findings Twelve phenolic metabolites including three phenolic acids, namely caffeic acid 1, rosmarinic acid 2 and methyl rosmarinate 3; four flavone glycosides viz the new compound luteolin 7-O-(4″,6″-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside 4, apigenin 7-O-β-D-rutinoside 5, cosmosiin 6 and cinaroside 7, together with four flavones aglycone, luteolin 8, apigenin 9, pedalitin 10 and crisiliol 11 in addition to one coumarin, 6,7-dihydroxycoumarin 12 were isolated from the leaves of S. splendens Sellow ex Roem & Schult. The AME of S. splendens was non toxic to mice up to 5 g/kg b.wt. it exhibited a significant hypoglycemic activity at 250 and 500 mg/kg as compared with control pre-drug (zero time) for each group as well as the diabetic control. Moreover, AME exhibited a significant antiinflammatory activity only at 1000 mg/kg in comparison to indomethacin. Finally, AME exhibited a marked significant scavenging activity against DPPH; the maximum reactive reaction rate after 5 min was 62.9, 82.5, 83.7, 84.3 and 85.1% for the concentrations 10, 20, 30, 40 and 50 mg/ml, respectively in comparison to L-ascorbic acid (86.8%). Conclusions This is the first study reporting the identification of a new flavone triglycoside, along with eleven known phenolic metabolites from AME of S. splendens. It showed significant hypoglycemic and antiinflammatory effects in dose dependant manner. Moreover it showed an in vitro antioxidant activity.
    No preview · Article · Nov 2012
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    ABSTRACT: Investigation of the aqueous alcoholic extract of Pyruscalleryana Decne. leaves led to the isolation of two new phenolic acids glycosides, namely protocatechuoylcalleryanin-3-O-β-glucopyranoside (1) and 3'-hydroxybenzyl-4-hydroxybenzoate-4'-O-β-glucopyranoside (2), together with nine known compounds among them lanceoloside A and methylgallate, which have been isolated for the first time from the genus Pyrus. Structures of the isolated compounds were established by spectroscopic analysis, including UV, IR, HRESI-MS, and 1D/2D NMR. The total extract and some isolated compounds were determined against DPPH (2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazinyl radical, for their free radical scavenging activity, the total alcoholic extract showed strong antioxidant activity while the two new compounds showed weak antioxidant activity.
    Full-text · Article · Jan 2011 · Carbohydrate research
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    ABSTRACT: A novel biflavone di-C-glucoside, 6,6"-di-C-beta-D-glucopyranoside-methylene-(8,8")-biapigenin (1), was isolated from the leaves of Jatropha curcas L. (Euphorbiaceae), together with six known compounds; apigenin 7-O-beta-D-neohesperidoside (2), apigenin 7-O-beta-D-galactoside (3), orientin (4), vitexin (5), vicenin II (6), and apigenin (7). Their structures were determined on the basis of extensive chemical and spectroscopic analyses (UV, NMR and HRESI-MS). The immunomodulatory effect of an 80% aqueous methanol extract (AME) and compounds 1-5 (0.25 mg/kg body wt) to one-day-old specific pathogen-free (SPF) chicks was determined. Stimulation of both humoral and cell-mediated seroresponse was observed, especially those of AME and compound 1. Remarkable effective increases of the antibody titers, lymphocyte and macrophage cells, in blood were recorded. SPF chicks treated with the tested samples exhibited protection against Newcastle disease challenge virus after being vaccinated.
    Preview · Article · Jul 2009 · Zeitschrift fur Naturforschung C
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    ABSTRACT: abstraCt Sixteen volatile compounds were identified from the n-hexane extract of the buds of Syzygium aromaticum by using gas chromatography-mass spectroscopy (GC-MS). The major components were eugenol (71.56 %) and eugenol acetate (8.99 %). The dichloromethane extract of the buds yielded limonin and ferulic aldehyde, along with eugenol. The flavonoids tamarixetin 3-O-b-D-glucopyranoside, ombuin 3-O-b-D-glu-copyranoside and quercetin were isolated from the ethanol extract; identifications of all these compounds were established by chemical and spectroscopic methods including 1D and 2D NMR. This is the first report of limonin, ferulic aldehyde and these flavonoids from this plant. All extracts and the isolated flavonoids showed strong antioxidant activity against 1, 2-diphenyl picrylhydrazyl (DPPH). Among the tested extracts, the ethanol extract of the clove buds showed remarkable scaven-ging activity, as compared with synthetic antioxidants such as butylated hydroxyl toluene (BHT). The ethanol extract of clove showed remarkable hepatoprotective activity against paracetamol-induced liver injury in female rats.
    Full-text · Article · Jan 2007

Publication Stats

53 Citations
2.48 Total Impact Points


  • 2012-2013
    • Jazan University
      • Department of Chemistry
      Djayzān, Jizan, Saudi Arabia
  • 2011
    • National Research Center, Egypt
      Al Qāhirah, Muḩāfaz̧at al Qāhirah, Egypt