Ashraf Khalil - Academia.edu (original) (raw)
Papers by Ashraf Khalil
Natural Product Communications, 2006
Four new sesquiterpene lactones, two heliangolides, one eudesmanolide and one germacranolide, wer... more Four new sesquiterpene lactones, two heliangolides, one eudesmanolide and one germacranolide, were isolated by chromatographic fractionation of an acetone extract of Eupatorium kiirunense and named eupakirunsins F, G H and I (1–4). They were identified as 8β-(3-hydroxy-2-methylen-butanoyloxy)-1β,10α-epoxy-3α-hydroxy-6βH,7αH-heliang-4Z,11(13)-dien-6,12-olide (1), 8β-tigloyloxy-1β,10α-epoxy-3β,15-dihydroxy-6βH,7αH-heliang-4Z,11(13)-dien-6,12-olide (2), 8β-tigloyloxy-1 β,3β-dihydroxy-6βH,7αH-eudesman-4(15),11(13)-dien-6,12-olide (3) and 8βtigloyloxy-3βhydroxy-1β,10β-epoxy-14-oxo-6βH,7αH-germacra-4E,11(13)-dien-6,12-olide (4). The structures and the relative configurations of the new metabolites were elucidated through extensive spectral analysis and by comparison with known spectral data. Among the isolated compounds, 1 and 3 exhibited potent cytotoxicity against WiDr and MCF-7 human tumor cell lines.
International Journal of Molecular Sciences, 2021
Natural chalcones possess antitumor properties and play a role as inducers of apoptosis, antioxid... more Natural chalcones possess antitumor properties and play a role as inducers of apoptosis, antioxidants and cytotoxic compounds. We recently reported that novel nitrogen chalcone-based compounds, which were generated in our lab, have specific effects on triple-negative breast cancer cells. However, the outcome of these two new compounds on human epidermal growth factor receptor 2 (HER2)-positive breast cancer remains nascent. Thus, we herein investigated the effects of these compounds (DK-13 and DK-14) on two HER2-positive breast cancer cell lines, SKBR3 and ZR75. Our data revealed that these compounds inhibit cell proliferation, deregulate cell-cycle progression and significantly induce cell apoptosis in both cell lines. Furthermore, the two chalcone compounds cause a significant reduction in the cell invasion ability of SKBR3 and ZR75 cancer cells. In parallel, we found that DK-13 and DK-14 inhibit colony formation of both cell lines in comparison to their matched controls. On the o...
薊罌粟中具有細胞毒活性之Benzophenanthridine 及Benzylisoquinoline 生物鹼
Phenolics and other constituents from Eclipta alba
Planta Medica, 1982
Phytochemistry, 1996
Three labdane-type diterpenes; 3-oxo-marrubiin and a mixture of two related C-15 epimeric diterpe... more Three labdane-type diterpenes; 3-oxo-marrubiin and a mixture of two related C-15 epimeric diterpenes based on 9~t,13~t,15,16-bisepoxy-15-hydroxy-3-oxo-labdan-6fl, 19-olide, in addition to the acylated flavone apigenin 7-O-[6"-O-(p-hydroxy-trans-cinnamoyl)glucoside-1 were isolated and identified from the aerial parts of Leucas neufliseana. Their structures were established through physical and chemical methods in addition to standard spectroscopic techniques. This is the first report of the isolation of the two epimeric diterpenes from a natural source.
Experimental Parasitology, 2018
Could Araucaria resin extract be used as a new treatment for toxoplasmosis?, heterophylla Experim... more Could Araucaria resin extract be used as a new treatment for toxoplasmosis?, heterophylla Experimental (2018),
Phytochemistry, 1997
A new isopimarane-type diterpene was isolated from the ethanol extract of the aerial parts of Nep... more A new isopimarane-type diterpene was isolated from the ethanol extract of the aerial parts of Nepeta septemcrenata. Its structure was established as Icu-hydroxy-7~~,14~,18-triacetoxy-isopimara-8,15-diene using different spectroscopic techniques (UV, IR, MS and 1 and 2D NMR). In addition, 7Gmethylapigenin was also isolated and identified.
Marine Drugs, 2022
Several natural products recovered from a marine-derived Aspergillus niger were tested for their ... more Several natural products recovered from a marine-derived Aspergillus niger were tested for their inhibitory activity against SARS CoV-2 in vitro. Aurasperone A (3) was found to inhibit SARS CoV-2 efficiently (IC50 = 12.25 µM) with comparable activity with the positive control remdesivir (IC50 = 10.11 µM). Aurasperone A exerted minimal cytotoxicity on Vero E6 cells (CC50 = 32.36 mM, SI = 2641.5) and it was found to be much safer than remdesivir (CC50 = 415.22 µM, SI = 41.07). To putatively highlight its molecular target, aurasperone A was subjected to molecular docking against several key-viral protein targets followed by a series of molecular dynamics-based in silico experiments that suggested Mpro to be its primary viral protein target. More potent anti-SARS CoV-2 Mpro inhibitors can be developed according to our findings presented in the present investigation.
Frajunolides E−K, Briarane Diterpenes from Junceella fragilis
Journal of Natural Products, 2008
Chemical investigation of the gorgonian octocoral Junceella fragilis, collected in Taiwan, result... more Chemical investigation of the gorgonian octocoral Junceella fragilis, collected in Taiwan, resulted in the isolation of seven new briarane-type diterpenes, frajunolides E-K (1-7), in addition to 14 known briaranes, praelolide, junceellin, junceellolides A-E, and K, 11a,20a-epoxy-4-deacetoxyjunceelolide D, umbraculolide A, junceellonoid A, and juncins Y, Z, and ZI, as well as ergosterol peroxide. The structures of 1-7 were determined by analysis of HRESIMS and 2D NMR spectroscopic data. Cytotoxicity and in vitro anti-inflammatory activities of compounds 1-7 were also evaluated.
Vibsane Diterpenoids from the Leaves and Flowers of Viburnum o doratissimum
J Nat Prod, 2004
Cespihypotins Q-V, Verticillene Diterpenoids from Cespitularia hypotentaculata
J Nat Prod, 2008
New Bioactive Clerodane Diterpenoids from the Roots ofCasearia membranacea
Chem Biodivers, 2008
Bioactive Marine Prostanoids from OctocoralClavularia viridis
Chem Biodivers, 2008
Irciformonins E?-?K, C 22 -Trinorsesterterpenoids from the Sponge Ircinia formosana
Helv Chim Acta, 2009
Four New Briarane Diterpenoids from the Gorgonian CoralJunceella fragilis
Helv Chim Acta, 2007
New Regio- and Stereoselective O -Deacetylated and Epoxy Products of Taxanes Isolated from Taxus m airei
J Nat Prod, 2004
Pregnane esters from Caralluma retrospiciens
Fitoterapia, 1995
Clavulazols A and B, Two New Pyrazine Derivatives from Clavularia Viridis
Journal of the Chinese Chemical Society, 2004
Cytotoxic Activity of Capnellene-8β, 10α-Diol Derivatives from a Taiwanese Soft Coral Capnella sp
Journal of the Chinese Chemical Society, 2008
Three New Cadinene Derivatives from Xenia Puerto-Galerae
Journal of the Chinese Chemical Society, 2007
Natural Product Communications, 2006
Four new sesquiterpene lactones, two heliangolides, one eudesmanolide and one germacranolide, wer... more Four new sesquiterpene lactones, two heliangolides, one eudesmanolide and one germacranolide, were isolated by chromatographic fractionation of an acetone extract of Eupatorium kiirunense and named eupakirunsins F, G H and I (1–4). They were identified as 8β-(3-hydroxy-2-methylen-butanoyloxy)-1β,10α-epoxy-3α-hydroxy-6βH,7αH-heliang-4Z,11(13)-dien-6,12-olide (1), 8β-tigloyloxy-1β,10α-epoxy-3β,15-dihydroxy-6βH,7αH-heliang-4Z,11(13)-dien-6,12-olide (2), 8β-tigloyloxy-1 β,3β-dihydroxy-6βH,7αH-eudesman-4(15),11(13)-dien-6,12-olide (3) and 8βtigloyloxy-3βhydroxy-1β,10β-epoxy-14-oxo-6βH,7αH-germacra-4E,11(13)-dien-6,12-olide (4). The structures and the relative configurations of the new metabolites were elucidated through extensive spectral analysis and by comparison with known spectral data. Among the isolated compounds, 1 and 3 exhibited potent cytotoxicity against WiDr and MCF-7 human tumor cell lines.
International Journal of Molecular Sciences, 2021
Natural chalcones possess antitumor properties and play a role as inducers of apoptosis, antioxid... more Natural chalcones possess antitumor properties and play a role as inducers of apoptosis, antioxidants and cytotoxic compounds. We recently reported that novel nitrogen chalcone-based compounds, which were generated in our lab, have specific effects on triple-negative breast cancer cells. However, the outcome of these two new compounds on human epidermal growth factor receptor 2 (HER2)-positive breast cancer remains nascent. Thus, we herein investigated the effects of these compounds (DK-13 and DK-14) on two HER2-positive breast cancer cell lines, SKBR3 and ZR75. Our data revealed that these compounds inhibit cell proliferation, deregulate cell-cycle progression and significantly induce cell apoptosis in both cell lines. Furthermore, the two chalcone compounds cause a significant reduction in the cell invasion ability of SKBR3 and ZR75 cancer cells. In parallel, we found that DK-13 and DK-14 inhibit colony formation of both cell lines in comparison to their matched controls. On the o...
薊罌粟中具有細胞毒活性之Benzophenanthridine 及Benzylisoquinoline 生物鹼
Phenolics and other constituents from Eclipta alba
Planta Medica, 1982
Phytochemistry, 1996
Three labdane-type diterpenes; 3-oxo-marrubiin and a mixture of two related C-15 epimeric diterpe... more Three labdane-type diterpenes; 3-oxo-marrubiin and a mixture of two related C-15 epimeric diterpenes based on 9~t,13~t,15,16-bisepoxy-15-hydroxy-3-oxo-labdan-6fl, 19-olide, in addition to the acylated flavone apigenin 7-O-[6"-O-(p-hydroxy-trans-cinnamoyl)glucoside-1 were isolated and identified from the aerial parts of Leucas neufliseana. Their structures were established through physical and chemical methods in addition to standard spectroscopic techniques. This is the first report of the isolation of the two epimeric diterpenes from a natural source.
Experimental Parasitology, 2018
Could Araucaria resin extract be used as a new treatment for toxoplasmosis?, heterophylla Experim... more Could Araucaria resin extract be used as a new treatment for toxoplasmosis?, heterophylla Experimental (2018),
Phytochemistry, 1997
A new isopimarane-type diterpene was isolated from the ethanol extract of the aerial parts of Nep... more A new isopimarane-type diterpene was isolated from the ethanol extract of the aerial parts of Nepeta septemcrenata. Its structure was established as Icu-hydroxy-7~~,14~,18-triacetoxy-isopimara-8,15-diene using different spectroscopic techniques (UV, IR, MS and 1 and 2D NMR). In addition, 7Gmethylapigenin was also isolated and identified.
Marine Drugs, 2022
Several natural products recovered from a marine-derived Aspergillus niger were tested for their ... more Several natural products recovered from a marine-derived Aspergillus niger were tested for their inhibitory activity against SARS CoV-2 in vitro. Aurasperone A (3) was found to inhibit SARS CoV-2 efficiently (IC50 = 12.25 µM) with comparable activity with the positive control remdesivir (IC50 = 10.11 µM). Aurasperone A exerted minimal cytotoxicity on Vero E6 cells (CC50 = 32.36 mM, SI = 2641.5) and it was found to be much safer than remdesivir (CC50 = 415.22 µM, SI = 41.07). To putatively highlight its molecular target, aurasperone A was subjected to molecular docking against several key-viral protein targets followed by a series of molecular dynamics-based in silico experiments that suggested Mpro to be its primary viral protein target. More potent anti-SARS CoV-2 Mpro inhibitors can be developed according to our findings presented in the present investigation.
Frajunolides E−K, Briarane Diterpenes from Junceella fragilis
Journal of Natural Products, 2008
Chemical investigation of the gorgonian octocoral Junceella fragilis, collected in Taiwan, result... more Chemical investigation of the gorgonian octocoral Junceella fragilis, collected in Taiwan, resulted in the isolation of seven new briarane-type diterpenes, frajunolides E-K (1-7), in addition to 14 known briaranes, praelolide, junceellin, junceellolides A-E, and K, 11a,20a-epoxy-4-deacetoxyjunceelolide D, umbraculolide A, junceellonoid A, and juncins Y, Z, and ZI, as well as ergosterol peroxide. The structures of 1-7 were determined by analysis of HRESIMS and 2D NMR spectroscopic data. Cytotoxicity and in vitro anti-inflammatory activities of compounds 1-7 were also evaluated.
Vibsane Diterpenoids from the Leaves and Flowers of Viburnum o doratissimum
J Nat Prod, 2004
Cespihypotins Q-V, Verticillene Diterpenoids from Cespitularia hypotentaculata
J Nat Prod, 2008
New Bioactive Clerodane Diterpenoids from the Roots ofCasearia membranacea
Chem Biodivers, 2008
Bioactive Marine Prostanoids from OctocoralClavularia viridis
Chem Biodivers, 2008
Irciformonins E?-?K, C 22 -Trinorsesterterpenoids from the Sponge Ircinia formosana
Helv Chim Acta, 2009
Four New Briarane Diterpenoids from the Gorgonian CoralJunceella fragilis
Helv Chim Acta, 2007
New Regio- and Stereoselective O -Deacetylated and Epoxy Products of Taxanes Isolated from Taxus m airei
J Nat Prod, 2004
Pregnane esters from Caralluma retrospiciens
Fitoterapia, 1995
Clavulazols A and B, Two New Pyrazine Derivatives from Clavularia Viridis
Journal of the Chinese Chemical Society, 2004
Cytotoxic Activity of Capnellene-8β, 10α-Diol Derivatives from a Taiwanese Soft Coral Capnella sp
Journal of the Chinese Chemical Society, 2008
Three New Cadinene Derivatives from Xenia Puerto-Galerae
Journal of the Chinese Chemical Society, 2007