0000000001304027
AUTHOR
Abiy Yenesew
showing 25 related works from this author
Crystal Structures and Cytotoxicity of ent-Kaurane-Type Diterpenoids from Two Aspilia Species
2018
A phytochemical investigation of the roots of Aspilia pluriseta led to the isolation of ent-kaurane-type diterpenoids and additional phytochemicals (1⁻23). The structures of the isolated compounds were elucidated based on Nuclear Magnetic Resonance (NMR) spectroscopic and mass spectrometric analyses. The absolute configurations of seven of the ent-kaurane-type diterpenoids (3⁻6, 6b, 7 and 8) were determined by single crystal X-ray diffraction studies. Eleven of the compounds were also isolated from the roots and the aerial parts of Aspilia mossambicensis. The literature NMR assignments for compounds 1 and 5 were revised. In a cytotoxicity assay, 12α-methoxy-ent-kaur-9(11),1…
Joziknipholones A and B: The First Dimeric Phenylanthraquinones, from the Roots ofBulbine frutescens
2007
From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P-co…
Cytotoxic flavonoids from two Lonchocarpus species
2018
A new isoflavone, 4′-prenyloxyvigvexin A (1) and a new pterocarpan, (6aR,11aR)-3,8-dimethoxybitucarpin B (2) were isolated from the leaves of Lonchocarpus bussei and the stem bark of Lonchocarpus eriocalyx, respectively. The extract of L. bussei also gave four known isoflavones, maximaisoflavone H, 7,2′-dimethoxy-3′,4′-methylenedioxyisoflavone, 6,7,3′-trimethoxy-4′,5′-methylenedioxyisoflavone, durmillone; a chalcone, 4-hydroxylonchocarpin; a geranylated phenylpropanol, colenemol; and two known pterocarpans, (6aR,11aR)-maackiain and (6aR,11aR)-edunol. (6aR,11aR)-Edunol was also isolated from the stem bark of L. eriocalyx. The structures of the isolated compounds were elucidated by spectrosco…
Naphthalene Derivatives from the Roots of Pentas parvifolia and Pentas bussei
2016
The phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Pentas parvifolia led to the isolation of three new naphthalenes, parvinaphthols A (1), B (2), and C (3), two known anthraquinones, and five known naphthalene derivatives. Similar investigation of the roots of Pentas bussei afforded a new polycyclic naphthalene, busseihydroquinone E (4), a new 2,2'-binaphthralenyl-1,1'-dione, busseihydroquinone F (5), and five known naphthalenes. All purified metabolites were characterized by NMR and MS data analyses, whereas the absolute configurations of 3 and 4 were determined by single-crystal X-ray diffraction studies. The E-geometry of compound 5 was supported by DFT-base…
Cytotoxic benzylbenzofuran derivatives from Dorstenia kameruniana
2018
Abstract Chromatographic separation of the extract of the roots of Dorstenia kameruniana (family Moraceae) led to the isolation of three new benzylbenzofuran derivatives, 2-(p-hydroxybenzyl)benzofuran-6-ol (1), 2-(p-hydroxybenzyl)-7-methoxybenzofuran-6-ol (2) and 2-(p-hydroxy)-3-(3-methylbut-2-en-1-yl)benzyl)benzofuran-6-ol(3) (named dorsmerunin A, B and C, respectively), along with the known furanocoumarin, bergapten (4). The twigs of Dorstenia kameruniana also produced compounds 1–4 as well as the known chalcone licoagrochalcone A (5). The structures were elucidated by NMR spectroscopy and mass spectrometry. The isolated compounds displayed cytotoxicity against the sensitive CCRF-CEM and …
Prenylated Flavonoids from the Roots of Tephrosia rhodesica
2020
Five new compounds—rhodimer (1), rhodiflavan A (2), rhodiflavan B (3), rhodiflavan C (4), and rhodacarpin (5)—along with 16 known secondary metabolites, were isolated from the CH2Cl2–CH3OH (1:1) extract of the roots of Tephrosia rhodesica. They were identified by NMR spectroscopic, mass spectrometric, X-ray crystallographic, and ECD spectroscopic analyses. The crude extract and the isolated compounds 2–5, 9, 15, and 21 showed activity (100% at 10 μg and IC50 = 5–15 μM) against the chloroquine-sensitive (3D7) strain of Plasmodium falciparum. peerReviewed
Cytotoxicity of fagaramide derivative and canthin-6-one from Zanthoxylum (Rutaceae) species against multidrug resistant leukemia cells
2019
In our continuous search for cytotoxic compounds from the genus Zanthoxylum, chromatographic separation of the MeOH/CH2Cl2 (1:1) extract of Z. chalybeum yielded one new alkamide; 4-(isoprenyloxy)-3-methoxy-3,4-deoxymethylenedioxyfagaramide (1) and a known one; fagaramide (2). Similarly, from the MeOH/CH2Cl2 (1:1) extract of the stem bark of Z. parachanthum four known compounds; canthin-6-one (3), dihydrochelerythrine (4), lupeol (5) and sesamin (6) were isolated. Characterization of the structures of these compounds was achieved using spectroscopic techniques (NMR and MS). Using resazurin reduction assay 1, 3 and 6 displayed moderate cytotoxicity with IC50 values below 50 μM against the dru…
Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis.
2015
Five new compounds, 4-O-geranylisoliquiritigenin (1), 12-dihydrousararotenoid B (2), 12-dihydrousararotenoid C (3), 4'-O-geranyl-7-hydroxyflavanone (4), and 4'-O-geranyl-7-hydroxydihydroflavanol (5), along with 12 known natural products (6-17) were isolated from the CH2Cl2/MeOH (1:1) extract of the root bark of Millettia usaramensis ssp. usaramensis by chromatographic separation. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas their absolute configurations were established on the basis of chiroptical data and in some cases also by X-ray crystallography. The crude extract was moderately active (IC50 = 11.63 μg/mL) against the ER-negative…
Cytotoxicity of isoflavones and biflavonoids from Ormocarpum kirkii towards multi-factorial drug resistant cancer.
2019
Abstract Background While incidences of cancer are continuously increasing, drug resistance of malignant cells is observed towards almost all pharmaceuticals. Several isoflavonoids and flavonoids are known for their cytotoxicity towards various cancer cells. Purpose The aim of this study was to determine the cytotoxicity of isoflavones: osajin (1), 5,7-dihydroxy-4ˈ-methoxy-6,8-diprenylisoflavone (2) and biflavonoids: chamaejasmin (3), 7,7″-di-O-methylchamaejasmin (4) and campylospermone A (5), a dimeric chromene [diphysin(6)] and an ester of ferullic acid with long alkyl chain [erythrinasinate (7)] isolated from the stem bark and roots of the Kenyan medicinal plant, Ormocarpum kirkii. The m…
Cytotoxic flavonoids from two Lonchocarpus species
2019
A new isoflavone, 4′-prenyloxyvigvexin A (1) and a new pterocarpan, (6aR,11aR)-3,8-dimethoxybitucarpin B (2) were isolated from the leaves of Lonchocarpus bussei and the stem bark of Lonchocarpus eriocalyx, respectively. The extract of L. bussei also gave four known isoflavones, maximaisoflavone H, 7,2′-dimethoxy-3′,4′-methylenedioxyisoflavone, 6,7,3′-trimethoxy-4′,5′-methylenedioxyisoflavone, durmillone; a chalcone, 4-hydroxylonchocarpin; a geranylated phenylpropanol, colenemol; and two known pterocarpans, (6aR,11aR)-maackiain and (6aR,11aR)-edunol. (6aR,11aR)-Edunol was also isolated from the stem bark of L. eriocalyx. The structures of the isolated compounds were elucidated by spectrosco…
Isoflavones and Rotenoids from the Leaves of Millettia oblata ssp. teitensis
2017
A new isoflavone, 8-prenylmilldrone (1), and four new rotenoids, oblarotenoids A−D (2−5), along with nine known compounds (6−14), were isolated from the CH2Cl2/CH3OH (1:1) extract of the leaves of Millettia oblata ssp. teitensis by chromatographic separation. The purified compounds were identified by NMR spectroscopic and mass spectrometric analyses, whereas the absolute configurations of the rotenoids were established on the basis of chiroptical data and in some cases by single-crystal X-ray crystallography. Maximaisoflavone J (11) and oblarotenoid C (4) showed weak activity against the human breast cancer cell line MDA-MB-231 with IC50 values of 33.3 and 93.8 μM, respectively. peerReviewed
CCDC 1409159: Experimental Crystal Structure Determination
2016
Related Article: Tsegaye Deyou, Ivan Gumula, Fangfang Pang, Amra Gruhonjic, Michael Mumo, John Holleran, Sandra Duffy, Paul A. Fitzpatrick, Matthias Heydenreich, Göran Landberg, Solomon Derese, Vicky Avery, Kari Rissanen, Máté Erdélyi, Abiy Yenesew|2015|J.Nat.Prod.|78|2932|doi:10.1021/acs.jnatprod.5b00581
CCDC 1868319: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199
CCDC 1061815: Experimental Crystal Structure Determination
2016
Related Article: Tsegaye Deyou, Ivan Gumula, Fangfang Pang, Amra Gruhonjic, Michael Mumo, John Holleran, Sandra Duffy, Paul A. Fitzpatrick, Matthias Heydenreich, Göran Landberg, Solomon Derese, Vicky Avery, Kari Rissanen, Máté Erdélyi, Abiy Yenesew|2015|J.Nat.Prod.|78|2932|doi:10.1021/acs.jnatprod.5b00581
CCDC 1868324: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199
CCDC 1061111: Experimental Crystal Structure Determination
2017
Related Article: Tsegaye Deyou, Marco Makungu, Matthias Heydenreich, Fangfang Pan, Amra Gruhonjic, Paul A. Fitzpatrick, Andreas Koch, Solomon Derese, Jerry Pelletier, Kari Rissanen, Abiy Yenesew, and Máté Erdélyi|2017|J.Nat.Prod.|80|2060|doi:10.1021/acs.jnatprod.7b00255
CCDC 1868322: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199
CCDC 1452354: Experimental Crystal Structure Determination
2016
Related Article: Negera Abdissa, Fangfang Pan, Amra Gruhonjic, Jürgen Gräfenstein, Paul A. Fitzpatrick, Göran Landberg, Kari Rissanen, Abiy Yenesew, Máté Erdélyi|2016|J.Nat.Prod.|79|2181|doi:10.1021/acs.jnatprod.6b00178
CCDC 1868321: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199
CCDC 1868320: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199
CCDC 1409160: Experimental Crystal Structure Determination
2016
Related Article: Tsegaye Deyou, Ivan Gumula, Fangfang Pang, Amra Gruhonjic, Michael Mumo, John Holleran, Sandra Duffy, Paul A. Fitzpatrick, Matthias Heydenreich, Göran Landberg, Solomon Derese, Vicky Avery, Kari Rissanen, Máté Erdélyi, Abiy Yenesew|2015|J.Nat.Prod.|78|2932|doi:10.1021/acs.jnatprod.5b00581
CCDC 1452353: Experimental Crystal Structure Determination
2016
Related Article: Negera Abdissa, Fangfang Pan, Amra Gruhonjic, Jürgen Gräfenstein, Paul A. Fitzpatrick, Göran Landberg, Kari Rissanen, Abiy Yenesew, Máté Erdélyi|2016|J.Nat.Prod.|79|2181|doi:10.1021/acs.jnatprod.6b00178
CCDC 1868318: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199
CCDC 1987379: Experimental Crystal Structure Determination
2020
Related Article: Yoseph Atilaw, Lois Muiva-Mutisya, Jonathan Bogaerts, Sandra Duffy, Arto Valkonen, Matthias Heydenreich, Vicky M. Avery, Kari Rissanen, Máté Erdélyi, Abiy Yenesew|2020|J.Nat.Prod.|83|2390|doi:10.1021/acs.jnatprod.0c00245
CCDC 1868323: Experimental Crystal Structure Determination
2020
Related Article: Souaibou Yaouba, Arto Valkonen, Paolo Coghi, Jiaying Gao, Eric M. Guantai, Solomon Derese, Vincent K. W. Wong, Máté Erdélyi, Abiy Yenesew|2018|Molecules|23|3199|doi:10.3390/molecules23123199