Gabrielle M Hill

Sana'a University, Şan‘ā’, Sanaa, Yemen

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Publications (7)6.49 Total impact

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    ABSTRACT: Oleanolic acid is a triterpenoid that has shown in vitro cytotoxic activity against human tumour cells and is known to be present in many higher plants.
    Anticancer research 08/2014; 34(8):4135-9. · 1.71 Impact Factor
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    ABSTRACT: The essential oil from the leaves of Tagetes minuta L., growing wild in Yemen, was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. A total of 28 compounds were identified representing 74.2% of total oil composition. Major components of the essential oil were (Z)-ocimenone (15.9%), (E)-ocimenone (34.8%), (Z)-beta-ocimene (8.3%), limonene (2.3%), (Z)-tagetone (1.8%), dihydrotagetone (1.4%) and an unidentified dimethylvinylketone derivative (20.6%). The oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC50 of 54.7 +/- 6.2 microg/mL. In the DPPH radical scavenging assay, T. minuta oil showed potent antiradical activity with an IC50 value of 36 microg/mL. Antimicrobial activity was also investigated on several microorganisms, and the essential oil exhibited high activity against methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition zone of 23 mm. It also exhibited remarkable antifungal activity against Candida albicans with an inhibition zone of 26 mm.
    Natural product communications 02/2014; 9(2):265-8. · 0.96 Impact Factor
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    ABSTRACT: The essential oil from the leaves of Tagetes minuta L., growing wild in Yemen, was obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. A total of 28 compounds were identified representing 74.2% of total oil composition. Major components of the essential oil were (Z)-ocimenone (15.9%), (E)-ocimenone (34.8%), (Z)-β-ocimene (8.3%), limonene (2.3%), (Z)-tagetone (1.8%), dihydrotagetone (1.4%) and an unidentified dimethylvinylketone derivative (20.6%). The oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC 50 of 54.7  6.2 μg/mL. In the DPPH radical scavenging assay, T. minuta oil showed potent antiradical activity with an IC 50 value of 36 µg/mL. Antimicrobial activity was also investigated on several microorganisms, and the essential oil exhibited high activity against methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition zone of 23 mm. It also exhibited remarkable antifungal activity against Candida albicans with an inhibition zone of 26 mm. In recent decades, the essential oils of aromatic plants have been of great interest as sources of bioactive natural products [1]. Antioxidants act as free radical-scavengers and either inhibit or slow down lipid peroxidation and other free radical-mediated processes. Therefore, they have a tendency to protect the body from various disorders which are attributed to free radicals such as cancer, arteriosclerosis, malaria, rheumatoid arthritis, neurodegenerative diseases and aging processes by protecting the organism against oxidative damage [2]. On the other hand, new sources of antimicrobial agents need to be discovered due to the existence and continuous evolution of resistant microorganisms, such as methicillin-resistant Staphylococcus aureus (MRSA). Around 90–95% of S. aureus strains world-wide are resistant to penicillin and in most Asian countries about 75% of the same bacterial strains are methicillin resistant [3,4] Essential oils and their volatile constituents have been widely used for bactericidal, fungicidal, spasmolytic, carminative, hepatoprotective, antiviral, antiparasitic, insecticidal, anticancer, antioxidant, antidiabetic, cardiovascular, and cosmetic and food applications [5-8]. Tagetes is a genus of 56 species [9] of annual and perennial, mostly herbaceous, plants in the Asteraceae. This genus is recognized as a source of carotenoids used as food colorants and feed additives [10], and for possessing anticancer and anti-aging effects [11],
    Natural product communications 01/2014; 9:4. · 0.96 Impact Factor
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    ABSTRACT: Bursera graveolens is a wild tree of commercial importance native to the Neotropics, which has been widely used in folk medicine. In the present study, the chemical composition and anti-proliferative properties of the essential oil from B. graveolens were assayed. The chemical composition of the essential oil, determined by GC-MS, was complex and dominated by limonene (26.5%). Bursera oil inhibited the growth of MCF-7 breast tumor cells as well as amastigotes of L. amazonensis, with IC50 values of 48.9 +/- 4.3 and 36.7 +/- 4.7 microg/mL, respectively. In addition, the cytotoxicity of the oil was 103.9 +/- 7.2 microg/mL against peritoneal macrophages from BALB/c mice. These results demonstrate that the essential oil from B. graveolens is a promissory antiproliferative product.
    Natural product communications 11/2012; 7(11):1531-4. · 0.96 Impact Factor
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    ABSTRACT: Four new prenylated isoflavones, rhynedulins A-C (1-3) and rhynedulinal (4), were isolated by bioassay-guided fractionation of the dichloromethane bark extract of Rhynchosia edulis. Five previously described compounds, scandenal, ulexin B, cajanone, cajanin, and cyclochandalone, were also isolated. These isoflavonoids showed weak inhibitory activity towards rhodesain, the major cathepsin-L like protease in Trypanosoma brucei. They also have weak antiproliferative activity towards MCF-7 cells.
    Natural product communications 11/2011; 6(11):1637-44. · 0.96 Impact Factor
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    ABSTRACT: The chemical composition of the essential oil obtained from the leaves of Pulicaria undulata Gamal Ed Din (syn P. orientalis sensu Schwartz and P. jaubertii Gamal Ed Din) was analyzed by GC-MS. Major compounds of P. undulata oil were the oxygenated monoterpenenes, carvotanacetone (91.4%) and 2,5-dimethoxy-p-cymene (2.6.%). The antimicrobial activity of the essential oil was evaluated against six microorganisms, Escherichia coli Pseudomonas aeruginosa, Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Candida albicans, using disc diffusion and broth microdilution methods. The oil showed the strongest bactericidal activity against Staphylococcus aureus and methicillin-resistant S. aureus, as well as Candida albicans 􀀀 The essential oil showed moderate cytotoxic activity against MCF-7 breast tumor cells, with an IC50 of 64.6 ± 13.7 μg/mL. Bioautographic assays were used to evaluate the acetylcholinesterase inhibitory effect as well as antifungal activity of the oil against Cladosporium cucumerinum
    Natural product communications 01/2011; 6:1-4. · 0.96 Impact Factor
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    Gabrielle M Hill, Debra M Moriarity, William N Setzer
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    ABSTRACT: Many anti-tumor drugs function by intercalating into DNA. The xanthine alkaloid caffeine can also intercalate into DNA as well as form π-π molecular complexes with other planar alkaloids and anti-tumor drugs. The presence of caffeine could interfere with the intercalating anti-tumor drug by forming π-π molecular complexes with the drug, thereby blocking the planar aromatic drugs from intercalating into the DNA and ultimately lowering the toxicity of the drug to the cancer cells. The cytotoxic activities of several known DNA intercalators (berberine, camptothecin, chelerythrine, doxorubicin, ellipticine, and sanguinarine) on MCF-7 breast cancer cells, both with and without caffeine present (200 μg/mL) were determined. Significant attenuation of the cytotoxicities by caffeine was found. Computational molecular modeling studies involving the intercalating anti-tumor drugs with caffeine were also carried out using density functional theory (DFT) and the recently developed M06 functional. Relatively strong π-π interaction energies between caffeine and the intercalators were found, suggesting an "interceptor" role of caffeine protecting the DNA from intercalation.
    Scientia Pharmaceutica 01/2011; 79(4):729-47.

Publication Stats

13 Citations
6.49 Total Impact Points

Institutions

  • 2014
    • Sana'a University
      Şan‘ā’, Sanaa, Yemen
  • 2011–2014
    • University of Alabama in Huntsville
      • Department of Chemistry
      Huntsville, Alabama, United States
  • 2012
    • Pedro Kourí Tropical Medicine Institute
      La Habana, Ciudad de La Habana, Cuba