Wafaa S Ahmed

Theodor Bilharz Research Institute, El-Gîza, Al Jīzah, Egypt

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Publications (5)6.67 Total impact

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    ABSTRACT: Chromatographic separation of an aqueous MeOH extract of Wisteria sinensis leaves has yielded six known flavonoids, two triterpene aglycones and the new acylated flavone glycoside chrysoeriol-7-O-[2''-O-(5'''-O-caffeoyl)-β-D-apiofuranosyl]-β-D-glucopyranoside (1). All metabolites were isolated for the first time from the genus Wisteria. Their structures were established on the basis of their chromatographic properties, chemical and physicochemical methods including acid hydrolysis analysis, spectroscopic (UV, 1 H-and 13 C-NMR) data and confirmed by ESI-MS analysis, as well as two-dimensional NMR (1 H-1 HCOSY, HMQC and HMBC). Biological studies of the defatted aqueous 80% methanol leaf extract and the major isolates 1, 6 and 7 were undertaken and they are reported herein for the first time to have significant cytotoxic activity against the Hep-G2 tumor cell line in addition to antioxidant activity.
    Molecules 12/2011; 16(12). · 2.43 Impact Factor
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    ABSTRACT: Phytochemical investigations of Calotropis procera leaves have led to the isolation of two new compounds: quercetagetin-6-methyl ether 3-O-beta-D-4C1-galacturonopyranoside (3) and (E)-3-(4-methoxyphenyl-2-O-beta-D-4C1 -glucopyranoside)-methyl propenoate (4), along with eleven known metabolites: nine flavonol and two cinnamic acid derivatives. All metabolites were isolated for the first time from the genus Calotropis, except for 1 isolated previously from Calotropis gigantea. The structures were determined by spectroscopic methods (UV, ESI-MS, 1H, 13C NMR, 1H-1H COSY, HSQC, and HMBC). The radical scavenging activity of the aqueous methanol extract and compounds 8-13 was measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Cytotoxic screening of the same compounds was carried out on brine shrimps as well.
    Zeitschrift fur Naturforschung C 01/2011; 66(11-12):547-54. · 0.60 Impact Factor
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    ABSTRACT: From the leaves of Duranta repens (Verbenaceae) two new triterpene saponins, named durantanin IV (1) and V (2)were isolated.In addition, ten known compounds were isolated, namely a bidesmosidic saponin, oleanolic acid, three phenylethanoids and five flavonoids. All metabolites were isolated for the first time from this genus except for 3 (oleanolic acid) and 7 (E/Z acteoside). The structures were determined mainly by spectroscopic methods (UV, IR, HRESI-MS, (1)H-, (13)C-NMR, (1)H-(1)H COSY, HSQC and HMBC). Cytotoxic screening of the chloroform, ethyl acetate and methanol extracts was carried out on brine shrimps. In addition, the investigated methanol extract and compounds 1, 2 and 7 showed significant cytotoxic activity against a HepG2 cell line.
    Molecules 02/2009; 14(5):1952-65. · 2.43 Impact Factor
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    ABSTRACT: The methanol extract of the leaves of Buddleja asiatica Lour. (Loganiaceae) showed antioxidant activity toward the well known in vitro antioxidant tests such as total antioxidant capacity by the phosphomolybdenum method, free radical scavenging activity by the 1,1-diphenyl-2-picrylhydrazyl scavenging assay (DPPH assay) and hydrogen peroxide scavenging methods. Due to the high scavenging activity of the n-butanol successive fraction toward DPPH and H2O2 (SC50 = 11.99 and 18.54 microg/ml, respectively), this extract was subjected to chromatographic separation and isolation. Four non-phenolic compounds were isolated and identified on the basis of spectroscopic and chemical analyses: 1-O-beta-D-glucopyranosyl-2-methoxy-3-(2-hydroxy-triaconta-3,12-dienoate)-glycerol (1), 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-beta-D-fucopyranosyl-olean-11,13(18)-diene-3 beta,23,28-triol (2), 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-beta-D-fucopyranosyl-olean-11,13(18)-diene-3,23,28-triol (3), and 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-acid-olean-11,13(18)-diene-3 beta,23,28-triol (4). The four compounds were evaluated as antioxidant agents using the three antioxidant bioassay tests.
    Zeitschrift fur Naturforschung C 01/2008; 63(7-8):483-91. · 0.60 Impact Factor
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    ABSTRACT: The methanol extract of the whole parts of Tribulus macropterus Boiss. (family Zygophyllaceae) showed cytotoxic activity against a human tumour cell line (hepatocyte generation 2, HepG2) (IC50 = 2.9 microg/ml). The n-butanolic fraction obtained from successive fractionation of the methanolic extract exhibited activity against HepG2 (IC50 = 2.6 microg/ml). Therefore, this fraction was subjected to separation using different chromatographic techniques. Five compounds, 1-5, were isolated and identified as: (22S,25S)-16beta,22,26-trihydroxy-cholest-4-en-3-one-16-O-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranoside (1), (22S,25S)-16beta,22,26-trihydroxy-cholest-4-en-3-one-16-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranoside (2), sucrose (3), D-pinitol (4) and 3beta-hydroxy-5a-pregn-16(17)en-20-one-3-O-beta-D-xylopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-ga-lactopyranoside (5) on the basis of spectroscopic and chemical data. The three steroidal compounds 1, 2 and 5 were also tested against the same cell line HepG2 and their IC50 values were 2.4, 2.2 and 1.1 microg/ml, respectively.
    Zeitschrift fur Naturforschung C 01/2007; 62(5-6):319-25. · 0.60 Impact Factor