Browsing by Author "Meyer, Debra"

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    Cytotoxic, cytostatic and HIV-1 PR inhibitory activities of the soft coral litophyton arboreum
    (MDPI, 2013) Ellithey, Mona S.; Lall, Namrita; Hussein, Ahmed A.; Meyer, Debra
    Bioassay-guided fractionation using different chromatographic and spectroscopic techniques in the analysis of the Red Sea soft coral Litophyton arboreum led to the isolation of nine compounds; sarcophytol M (1), alismol (2), 24-methylcholesta-5,24(28)-diene-3β-ol (3), 10-O-methyl alismoxide (4), alismoxide (5), (S)-chimyl alcohol (6), 7β-acetoxy-24-methylcholesta-5-24(28)-diene-3,19-diol (7), erythro-N-dodecanoyl-docosasphinga-(4E,8E)-dienine (8), and 24-methylcholesta-5,24 (28)-diene-3β,7β,19-triol (9). Some of the isolated compounds demonstrated potent cytotoxic- and/or cytostatic activity against HeLa and U937 cancer cell lines and inhibitory activity against HIV-1 protease (PR). Compound 7 was strongly cytotoxic against HeLa cells (CC50 4.3 ± 0.75 μM), with selectivity index of SI 8.1, which was confirmed by real time cell electronic sensing (RT-CES). Compounds 2, 7, and 8 showed strong inhibitory activity against HIV-1 PR at IC50s of 7.20 ± 0.7, 4.85 ± 0.18, and 4.80 ± 0.92 μM respectively. In silico docking of most compounds presented comparable scores to that of acetyl pepstatin, a known HIV-1 PR inhibitor. Interestingly, compound 8 showed potent HIV-1 PR inhibitory activity in the absence of cytotoxicity against the cell lines used. In addition, compounds 2 and 5 demonstrated cytostatic action in HeLa cells, revealing potential use in virostatic cocktails. Taken together, data presented here suggest Litophyton arboreum to contain promising compounds for further investigation against the diseases mentioned.
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    Inhibition of HIV-1 enzymes, antioxidant and anti-inflammatory activities of Plectranthus barbatus
    (Elsevier, 213) Kapewangolo, Petrina; Hussein, Ahmed A.; Meyer, Debra
    Ethnopharmacological relevance: Plectranthus barbatus is widely used in African countries as an herbal remedy to manage HIV/AIDS and related conditions. Aim of the study: To investigate the HIV-1 inhibitory, anti-inflammatory and antioxidant properties of P. barbatus and thereby provide empirical evidence for the apparent anecdotal success of the extracts. Materials and methods: Ethanolic extract of P. barbatus's leaves was screened against two HIV-1 enzymes: protease (PR) and reverse transcriptase (RT). Cytotoxicity of the extract was determined through measuring tetrazolium dye uptake of peripheral blood mononuclear cells (PBMCs) and the TZM-bl cell line. Confirmatory assays for cytotoxicity were performed using flow cytometry and real-time cell electronic sensing (RT-CES). The free radical scavenging activity of the extract was investigated with 2,2- diphenyl-1-picrylhydrazyl while the anti-inflammatory properties of the plant extract were investigated using a Th1/Th2/Th17 cytometric bead array technique.