TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Meisner, M. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Two prenylated flavanones from stem bark of erythrina burttii Y1 - 1998 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Four isoflavanones from stem bark of erythrina sacleuxii Y1 - 1998 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Schanzenbach, Dirk A1 - Peter, Martin G. T1 - Two Isoflavanones from the Stem Bark of Erythrina sacleuxii N2 - From the stem bark of Erythrina sacleuxii two new isoflavanones, (R)-5,7-dihydroxy-2',4',5'- trimethoxyisoflavanone (trivial name, (R)-2,3-dihydro-7-demethylrobustigenin) and (R)-5-hydroxy- 2',4',5'-trimethoxy-2'',2''- dimethylpyrano[5'',6'':6,7]isoflavanone (trivial name, (R)-saclenone) were isolated. In addition the known compounds shinpterocarpin, 2,3-dehydrokievitone, abyssinone V, abyssinone V-4'-methyl ether, erythrinasinate and 4'-O-methylsigmoidin B were isolated. The structures were determined on the basis of spectroscopic evidence. Y1 - 2000 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Guchu, S. M. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Three iosoflav-3-enes and a 2-arylbenzofuran from the root bark of Erythrina burttii N2 - From the root bark of Erythrina burttii three new isoflav-3-enes, 7,4'-dihydroxy-2'-methoxy-6- (1'',1''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-A), 4'-hydroxy-2'- methoxy-(2'',2''-dimethylpyrano[5'',6'':8,7]isoflav-3-ene (trivial name, burttinol-B), 7,4'-dihydroxy-2'-methoxy-8-(3'',3''-dimethylallyl)isoflav-3-ene (trivial name, burttinol-C), and a new 2-arylbenzofuran, 6,4'-dihydroxy-2'-methoxy-5- (1'',1''-dimethylallyl)-2-arylbenzofuran (trivial name, burttinol-D) were isolated. In addition, the known compounds, abyssinone V-4'-methyl ether, bidwillol A, calopocarpin, erybraedin A, erythrabyssin II, isobavachalcone, phaseollidin and phaseollin were identified. The structures were determined on the basis of spectroscopic evidence. Y1 - 2002 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Irungu, Beatrice A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Two prenylated flavonoids from the stem bark of Erythrina burttii N2 - From the stem bark of Erythrina burttii, a new isoflavone, 5,2',4'-trihydroxy-7-methoxy-6-(3- methylbut-2-enyl)isoflavone (trivial name, 7-O-methylluteone) and a new flavanone, 5,7-dihydroxy-4'-methoxy- 3'-(3-methylbutadienyl)-5'-(3-methylbut-2-enyl)flavanone (trivial name, burttinonedehydrate) along with three known isoflavonoids (8-prenylluteone, 3-O-methylcalopocarpin and genistein) were isolated. The structures were detd. on the basis of spectroscopic evidence. Y1 - 2003 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Induli, M. A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. A1 - Akala, Hoseah M. A1 - Wangui, Julia A1 - Liyala, Pamela A1 - Waters, Norman C. T1 - Anti-plasmodial flavonoids from the stem bark of Erythrina abyssinica N2 - The ethyl acetate extract of the stem bark of Erythrina abyssinica showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of 7.9 +/- 1.1 and 5.3 +/- 0.7 mug/ml, respectively. From this extract, a new chalcone, 2,3,4,4'-tetrahydroxy-5- prenylchalcone (trivial name 5-prenylbutein) and a new flavanone, 4',7-dihydroxy-3'-methoxy-5'- prenylflavanone (trivial name, 5-deoxyabyssinin II) along with known flavonoids have been isolated as the anti- plasmodial principles. The structures were determined on the basis of spectroscopic evidence. (C) 2004 Elsevier Ltd. All rights reserved Y1 - 2004 SN - 0031-9422 ER - TY - JOUR A1 - Wanjohi, John M. A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Peter, Martin G. A1 - Dreyer, M. A1 - Reichert, M. A1 - Bringmann, Gerhard T1 - Three dimeric anthracene derivatives from the fruits of Bulbine abyssinica N2 - From the fruits of Bulbine abyssinica three new dimeric anthracene derivatives, (P)-8,9,1',8'- tetrahydroxy-3,3'-dimethyl[10,7'-bianthracene]-1,4,9',10'- tetraone (trivial name abyquinone A), (10R)-1,4,8,1',8-pentahydroxy-3,3'-dimethyl-[10,7'-bianthracene]9,9',10' (10H)-trione (trivial name abyquinone B), and (10R)-3,4'-dihydro-1,4,8,3',8',9'-hexahydroxy-3,3'- dimethyl-[10,7'-biant hracene]9,1'(10H,2'H)-dione (trivial name abyquinone Q were isolated. Despite their structural differences, these three compounds are connected to each other by the apparently biomimetic conversion of abyquinone C (a preanthraquinonylanthrone with two stereogenic centers) into B (an anthraquinonylanthrone with one stereogenic center) and finally into A (an axially chiral bianthraquinone) under mild conditions, involving a highly efficient center-to-axis chirality transfer. In addition, the known anthraquinones islandicin and chrysophanol were identified. The structures were determined on the basis of spectroscopical evidences, chemical transformations, and quantum chemical CD calculations. (C) 2005 Elsevier Ltd. All rights reserved Y1 - 2005 SN - 0040-4020 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Mushibe, E. K. A1 - Induli, M. A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Kabaru, Jacques M. A1 - Heydenreich, Matthias A1 - Koch, Andreas A1 - Peter, Martin G. T1 - 7a-O-methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoloata N2 - From the acetone extract of the roots of Derris trifoliata an isollavonoid derivative, named 7a-O- methyldeguelol, a modified rotenoid with an open ring-C, representing a new sub-class of isollavonoids (the sub-class is here named as rotenoloid), was isolated and characterised. In addition, the known rotenoids, rotenone, deguelin and alpha-toxicarol, were identified. The structures were determined on the basis of spectroscopic evidence. Rotenone and deguelin were identified as the larvicidal principles of the acetone extract of the roots of Derris trifoliata. (c) 2005 Elsevier Ltd. All rights reserved Y1 - 2005 SN - 0031-9422 ER - TY - JOUR A1 - Yenesew, Abiy A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Bii, Christine C. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Antimicrobial flavonoids from the stem bark of Erythrina burttii N2 - The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed against fungi and Gram(+) bacteria, but the Gram(-) bacteria Escherichia coli was resistant. (c) 2005 Elsevier B.V. All rights reserved Y1 - 2005 SN - 0367-326X ER - TY - JOUR A1 - Yenesew, Abiy A1 - Kiplagat, John T. A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Kabaru, Jacques M. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata N2 - The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a rotenoloid (named 7a-O-methyl-12a-hydroxydeguelol) and a spirohomooxarotenoid (named spiro-13-homo-13-oxaelliptone), were isolated and characterised. In addition a rare natural chromanone (6,7-dimethoxy-4-chromanone) and the known rotenoids rotenone, tephrosin and dehydrodeguelin were identified. The structures were assigned on the basis of spectroscopic evidence. The larvicidal activity of the crude extract is mainly due to rotenone. (c) 2006 Elsevier Ltd. All rights reserved Y1 - 2006 UR - http://www.sciencedirect.com/science/article/pii/S0031942206000045 U6 - https://doi.org/10.1016/j.phytochem.2006.01.002 ER - TY - JOUR A1 - Andayi, Andrew W. A1 - Yenesew, Abiy A1 - Derese, Solomon A1 - Midiwo, Jacob O. A1 - Gitu, Peter M. A1 - Jondiko, Ogoche J. I. A1 - Akala, Hoseah M. A1 - Liyala, Pamela A1 - Wangui, Julia A1 - Waters, Norman C. A1 - Heydenreich, Matthias A1 - Peter, Martin G. T1 - Antiplasmodial flavonoids from Erythrina sacleuxii N2 - The acetone extracts of the root bark and stem bark of Erythrina sacleuxii showed antiplasmodial activities against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the acetone extract of the root bark afforded a new isoflavone, 7-hydroxy-4 -methoxy-3'- prenylisoflavone (trivial name 5-deoxy-3' - prenylbiochanin A) along with known isoflavonoids as the antiplasmodial principles. Flavonoids and isoflavonoids isolated from the stem bark of E. sucleuxii were also tested and showed antiplasmodial activities. The structures were determined on the basis of spectroscopic evidence Y1 - 2006 UR - http://www.thieme-connect.com/ejournals/toc/plantamedica U6 - https://doi.org/10.1055/s-2005-873200 SN - 0032-0943 ER - TY - JOUR A1 - Bringmann, Gerhard A1 - Mutanyatta-Comar, Joan A1 - Maksimenka, Katja A1 - Wanjohi, John M. A1 - Heydenreich, Matthias A1 - Brun, Reto A1 - Müller, Werner E. G. A1 - Peter, Martin G. A1 - Midiwo, Jacob O. A1 - Yenesew, Abiy T1 - Joziknipholones A and B : the first dimeric phenylanthraquinones, from the roots of Bulbine frutescens N2 - 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- configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M-configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells. Y1 - 2008 UR - http://www3.interscience.wiley.com/journal/26293/home?CRETRY=1&SRETRY=0 SN - 0947-6539 ER - TY - JOUR A1 - Machumi, Francis A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. A1 - Heydenreich, Matthias A1 - Kleinpeter, Erich A1 - Tekwani, Babu L. A1 - Khan, Shabana I. A1 - Walker, Larry A. A1 - Muhammad, Ilias T1 - Antiparasitic and anticancer carvotacetone derivatives of Sphaeranthus bullatus JF - Natural product communications : an international journal for communications and reviews N2 - The CH2Cl2-MeOH (1:1) extract of the aerial parts of Sphaeranthus bullatus, an annual herb native to tropical East Africa, showed activity against chloroquine sensitive D6 (IC50 9.7 mu g/mL) and chloroquine resistant W2 (IC50 15.0 mu g/mL) strains of Plasmodium falciparum. Seventeen secondary metabolites were isolated from the extract through conventional chromatographic techniques and identified using various spectroscopic methods. The compounds were evaluated for their in vitro antiplasmodial, antileishmanial and anticancer activities revealing activity of four carvotacetone derivatives, namely 3-acetoxy-7-hydroxy-5-tigloyloxycarvotacetone (1) 3,7-dihydroxy-5-tigloyloxycarvotacetone (2), 3-acetoxy-5,7-dihydroxycarvotacetone (3) and 3,5,7-trihydroxycarvotacetone (4); with antiplasmodial IC50 values of 1.40, 0.79, 0.60 and 3.40 mu g/mL, respectively, against chloroquine sensitive D6 strains of P. falciparum; antiplasmodial activity of IC50 2.00, 0.90, 0.68 and 2.80 mu g/mL respectively, against chloroquine resistant W2 strains of P. falciparum, antileishmanial IC50, values of 0.70, 3.00, 0.70 and 17.00 mu g/mL, respectively, against the parasite L. donovanii promastigotes, and anticancer activity against human SK-MEL, KB, BT-549 and SK-OV-3 tumor cells, with IC50 values between <1.1 - 5.3 mu g/mL, for 1-3. In addition, cytotoxic effects of the active compounds were evaluated against monkey kidney fibroblasts (VERO) and pig kidney epithelial cells (LLC-PK11). The structures of carvotacetone derivatives were determined by ID and 2D NMR spectroscopy; the absolute stereochemical configuration of 3-acetoxy-7-hydroxy-5-tigloyloxycarvotacetone (I) was determined as 3R, 4R, 5S by circular dichroism, specific rotation, H-1 NMR and 2D NMR ROESY and NOESY experiments. KW - Sphaeranthus bullatus KW - Asteraceae KW - Antiplasmodial KW - Antileishmanial KW - Anticancer KW - Carvotacetones Y1 - 2012 SN - 1934-578X VL - 7 IS - 9 SP - 1123 EP - 1126 PB - NPC CY - Westerville ER - TY - JOUR A1 - Abdissa, Negera A1 - Induli, Martha A1 - Akala, Hoseah M. A1 - Heydenreich, Matthias A1 - Midiwo, Jacob O. A1 - Ndakala, Albert A1 - Yenesew, Abiy T1 - Knipholone cyclooxanthrone and an anthraquinone dimer with antiplasmodial activities from the roots of Kniphofia foliosa JF - Phytochemistry letters N2 - A new phenylanthrone, named knipholone cyclooxanthrone and a dimeric anthraquinone, 10-methoxy-10,7'-(chrysophanol anthrone)-chrysophanol were isolated from the roots of Kniphofia foliosa together with the rare naphthalene glycoside, dianellin. The structures were determined by NMR and mass spectroscopic techniques. The compounds showed antiplasmodial activities against the chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum with 10-methoxy-10,7'-(chrysophanol anthrone)-chrysophanol being the most active with IC50 values of 1.17 +/- 0.12 and 4.07 +/- 1.54 mu g/ml, respectively. KW - Kniphofia foliosa KW - Asphodelaceae KW - Roots KW - Anthraquinone KW - Knipholone cyclooxanthrone KW - 10-Methoxy-10,7 '-(chrysophanol anthrone)-chrysophanol KW - Dianellin KW - Malaria Y1 - 2013 U6 - https://doi.org/10.1016/j.phytol.2013.02.005 SN - 1874-3900 VL - 6 IS - 2 SP - 241 EP - 245 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Omosa, Leonidah K. A1 - Amugune, Beatrice A1 - Ndunda, Beth A1 - Milugo, Trizah K. A1 - Heydenreich, Matthias A1 - Yenesew, Abiy A1 - Midiwo, Jacob O. T1 - Antimicrobial flavonoids and diterpenoids from Dodonaea angustifolia JF - South African journal of botany : an international interdisciplinary journal for botanical sciences KW - Dodonaea angustifolia KW - Surface exudates KW - Flavone KW - Flavanone KW - Diterpenoid KW - Antimicrobial activities Y1 - 2014 U6 - https://doi.org/10.1016/j.sajb.2013.11.012 SN - 0254-6299 SN - 1727-9321 VL - 91 SP - 58 EP - 62 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Abdissa, Negera A1 - Heydenreich, Matthias A1 - Midiwo, Jacob O. A1 - Ndakala, Albert A1 - Majer, Zsuzsanna A1 - Neumann, Beate A1 - Stammler, Hans-Georg A1 - Sewald, Norbert A1 - Yenesew, Abiy T1 - A xanthone and a phenylanthraquinone from the roots of Bulbine frutescens, and the revision of six seco-anthraquinones into xanthones JF - Phytochemistry letters N2 - Phytochemical investigation of the dichloromethane/methanol (1:1) extract of the roots of Bulbine frutescens led to the isolation of a new xanthone, 8-hydroxy-6-methylxanthone-1-carboxylic acid (1) and a new phenylanthraquinone, 6',8-O-dimethylknipholone (2) along with six known compounds. The structures were elucidated on the basis of NMR and MS spectral data analyses. The structure of compound 1 was confirmed through X-ray crystallography which was then used as a reference to propose the revision of the structures of six seco-anthraquinones into xanthones. The isolated compounds were evaluated for cytotoxicity against human cervix carcinoma KB-3-1 cells with the phenylanthraquinone knipholone being the most active (IC50 = 0.43 mu M). Two semi-synthetic knipholone derivatives, knipholone Mannich base and knipholone-1,3-oxazine, were prepared and tested for cytotoxic activity; both showed moderate activities (IC50 value of 1.89 and 2.50 mu M, respectively). (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved. KW - Bulbine frutescens KW - Xanthone KW - seco-Anthraquinone KW - Phenylanthraquinone KW - Cytotoxicity KW - Structure revision Y1 - 2014 U6 - https://doi.org/10.1016/j.phytol.2014.04.004 SN - 1874-3900 SN - 1876-7486 VL - 9 SP - 67 EP - 73 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Irungu, Beatrice N. A1 - Adipo, Nicholas A1 - Orwa, Jennifer A. A1 - Kimani, Francis A1 - Heydenreich, Matthias A1 - Midiwo, Jacob O. A1 - Bjoremark, Per Martin A1 - Hakansson, Mikael A1 - Yenesew, Abiy A1 - Erdelyi, Mate T1 - Antiplasmodial and cytotoxic activities of the constituents of Turraea robusta and Turraea nilotica JF - Journal of ethnopharmacology : an interdisciplinary journal devoted to bioscientific research on indigenous drugs N2 - Ethnopharmacological relevance: Turraea robusta and Turraea nilotica are African medicinal plants used for the treatment of a wide variety of diseases, including malaria. The genus Turraea is rich in limonoids and other triterpenoids known to possess various biological activities. Materials and methods: From the stem bark of T. robusta six compounds, and from various parts of T nilotica eleven compounds were isolated by the use of a combination of chromatographic techniques. The structures of the isolated compounds were elucidated using NMR and MS, whilst the relative configuration of one of the isolated compounds, toonapubesin F, was established by X-ray crystallography. The antiplasmodial activities of the crude extracts and the isolated constituents against the D6 and W2 strains of Plasmodium falciparum were determined using the semiautomated micro dilution technique that measures the ability of the extracts to inhibit the incorporation of (G-H-3, where G is guanine) hypoxanthine into the malaria parasite. The cytotoxicity of the crude extracts and their isolated constituents was evaluated against the mammalian cell lines African monkey kidney (vero), mouse breast cancer (4T1) and human larynx carcinoma (HEp2). Results: The extracts showed good to moderate antiplasmodial activities, where the extract of the stem bark of T. robusta was also cytotoxic against the 4T1 and the HEp2 cells (IC50 < 10 mu g/ml). The compounds isolated from these extracts were characterized as limonoids, protolimonoids and phytosterol glucosides. These compounds showed good to moderate activities with the most active one being azadironolide, IC50 2.4 +/- 0.03 mu M and 1.1 +/- 0.01 mu M against the D6 and W2 strains of Plasmodium falciparum, respectively; all other compounds possessed IC50 14.4-40.5 mu M. None of the compounds showed significant cytotoxicity against vero cells, yet four of them were toxic against the 4T1 and HEp2 cancer cell lines with piscidinol A having IC50 8.0 +/- 0.03 and 8.4 +/- 0.01 mu M against the 4T1 and HEp2 cells, respectively. Diacetylation of piscidinol A resulted in reduced cytotoxicity. Conclusion: From the medicinal plants T. robusta and T. nilotica, twelve compounds were isolated and characterized; two of the isolated compounds, namely 11-epi-toonacilin and azadironolide showed good antiplasmodial activity with the highest selectivity indices. (C) 2015 The Authors. Published by Elsevier Ireland Ltd. KW - Turraea robusta KW - Turraea nilotica KW - Antiplasmodial activity KW - Cytotoxicity KW - Limonoid KW - Toonapubesins F KW - Toonacilin KW - Azadironolide Y1 - 2015 U6 - https://doi.org/10.1016/j.jep.2015.08.039 SN - 0378-8741 VL - 174 SP - 419 EP - 425 PB - Elsevier CY - Clare ER -