Mahmoud Abu-Asaker

Ankara University, Ankara, Ankara, Turkey

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Publications (4)

  • Source
    Ilkay Orhan · Murat Kartal · Mahmoud Abu-Asaker · [...] · Bilge Şener
    [Show abstract] [Hide abstract] ABSTRACT: Antioxidant activity of the ethanolic extracts of the fruits of Fritillaria pontica Wahlenb. (Liliaceae), Euonymus latifolius (L.) Mill. ssp. latifolius (Celastraceae), and Vicia sativa L. ssp. nigra (L.) Ehrh. var. nigra L. (Fabaceae), the aerial parts of Turritis laxa (Sibth & Sm.) Hayek (Brassicaceae), Vicia cracca L. (Fabaceae), and Oxyria digyna (L.) Hill. (Polygonaceae) was screened by 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric-reducing antioxidant power (FRAP) assays at 0.5, 1.0, and 2.0mgml−1 concentrations. Total phenolic contents of the extracts were determined using Folin-Ciocalteau reagent. T. laxa was also tested for its anti-acetylcholinesterase activity. The extracts were analyzed by LC–DAD–MS for their flavonoid content and the ethanolic extract of T. laxa has been found to contain rutin in appreciable amounts (7.63±0.2%). Rutin and hyperoside were detected qualitatively in F. pontica, where vitexin was identified in O. digyna. It was also the most active in the antioxidant tests.
    Full-text Article · May 2009 · Food Chemistry
  • Source
    Murat Kartal · Mahmoud Abu-Asaker · Margita Dvorska · [...] · Milan Zemlicka
    [Show abstract] [Hide abstract] ABSTRACT: Pomiferin and osajin are major bioactive isoflavones found in Maclura pomifera (Rafin.) Schneider (Moraceae). A simple, reproducible, and sensitive method for analysis of pomiferin and osajin in different parts of M. pomifera has been developed and validated. The compounds were separated on a C8 column by gradient elution at a flow rate at 1.0mLmin−1. Column eluent was monitored at 280nm by use of a diode-array detector. Linear range, peak purity, selectivity, system performance, precision, accuracy, and robustness were shown to be acceptable. LC–MS with atmospheric pressure electrospray ionization was used for identification of the compounds; use of positive-ion mode resulted in protonated pseudomolecular ions of the compounds.
    Full-text Article · Jan 2009 · Chromatographia
  • [Show abstract] [Hide abstract] ABSTRACT: Five new triterpene saponins, 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol (1), 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-22-O-angeloyl-R1-barrigenol (2), 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-21-O-acetyl-22-O-angeloyl-R1-barrigenol (3), 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-21-O-acetyl-22-O-beta,beta-dimethylacryloyl-R1-barrigenol (4), and 3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-d-glucuronopyranosyl-22-O-angeloyl-28-O-acetyl-R1-barrigenol (5), were isolated from the roots of Eryngium campestre. Their structures were established mainly by 2D NMR techniques and mass spectrometry. Compounds 1-4 and 3-O-beta-d-glucopyranosyl-(1-->2)-[alpha-l-rhamnopyranosyl-(1-->4)]-beta-d-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol, previously isolated from the same plant, showed a weak cytotoxicity when tested against HCT 116 and HT 29 human colon cancer cells.
    Article · Jul 2006 · Journal of Natural Products
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    [Show abstract] [Hide abstract] ABSTRACT: Two new triterpene saponins, 3-O-beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucuronopyranosyl-22-O-angeloyl-R1-barrigenol (1) and 3-O-beta-D-glucopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucuronopyranosyl-22-O-beta,beta-dimethylacryloyl-A1-barrigenol (2), were isolated from the roots of Eryngium campestre (Apiaceae). Their structures were established mainly by 2D NMR techniques and mass spectrometry.
    Full-text Article · Oct 2005 · CHEMICAL & PHARMACEUTICAL BULLETIN