@article{PazBecerraSilvaetal.2016, author = {Paz, Cristian and Becerra, Jose and Silva, Mario and Cabrera-Pardo, Jaime and Burgos, Viviana and Heydenreich, Matthias and Schmidt, Bernd}, title = {(-)-8-Oxohobartine a New Indole Alkaloid from Aristotelia chilensis (Mol.) Stuntz}, series = {Records of Natural Products}, volume = {10}, journal = {Records of Natural Products}, publisher = {ACG Publications}, address = {Gebze-Kocaeli}, issn = {1307-6167}, pages = {68 -- 73}, year = {2016}, abstract = {The fruit of Aristotelia chilensis is considered a "super fruit" due to its high concentration of polyphenols displaying exceptional antioxidant capacities ORAC. From maqui berries have been reported several anthocyanins and glycosylated flavonoids, those benefits increase the attention to restudy the plant. From the leaves of A. chilensis several indole alkaloids have been reported, we in addition to aristoteline, aristone, aristoquinoline and 3-fromylindole report the spectroscopic elucidation of 8-oxo-9-dehydromakomakine (1), hobartine (2) and a new alkaloid named 8-oxohobartine (3). Compound 1 to 3 did not show bactericidal activity against E. coli and S. aureus till 200 mu g.}, language = {en} } @article{PazBecerraSilvaetal.2015, author = {Paz, Cristian and Becerra, Jose and Silva, Mario and Burgos, Viviana and Heydenreich, Matthias and Schmidt, Bernd and Thu Tran, and Vetter, Irina}, title = {(-)-Pentylsedinine, a New Alkaloid from the Leaves of Lobelia tupa with Agonist Activity at Nicotinic Acetylcholine Receptor}, series = {Natural product communications : an international journal for communications and reviews}, volume = {10}, journal = {Natural product communications : an international journal for communications and reviews}, number = {8}, publisher = {NPC}, address = {Westerville}, issn = {1934-578X}, pages = {1355 -- 1357}, year = {2015}, abstract = {Lobelia tupa, also called devil's tobacco, is a native plant from the center-south of Chile which has been used by the native people of Chile as a hallucinogenic and anesthetic plant. A new piperidine alkaloid, called pentylsedinine, which comprises five carbons in the side chain, was isolated from the aerial part of L. tupa, along with lobeline and lobelanidine. The structure was established on the basis of 1D and 2D NMR spectroscopy. While lobeline is a neutral antagonist at alpha 3 beta 2/alpha 3 beta 4 nAChR and alpha 7 nAChR, both lobelanidine and pentylsedinine act as partial agonists at nAChR}, language = {en} } @article{ShainyanSuslovaTranDinhPhienetal.2019, author = {Shainyan, Bagrat A. and Suslova, Elena N. and Tran Dinh Phien, and Shlykov, Sergey A. and Heydenreich, Matthias and Kleinpeter, Erich}, title = {1-Methylthio-1-phenyl-1-silacyclohexane: Synthesis, conformational preferences in gas and solution by GED, NMR and theoretical calculations}, series = {Tetrahedron}, volume = {75}, journal = {Tetrahedron}, number = {46}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2019.130677}, pages = {9}, year = {2019}, abstract = {1-Methylthio-1-phenyl-1-silacyclohexane 1, the first silacyclohexane with the sulfur atom at silicon, was synthesized and its molecular structure and conformational preferences studied by gas-phase electron diffraction (GED) and low temperature C-13 and Si-29 NMR spectroscopy (LT NMR). Quantum-chemical calculations were carried out both for the isolated species and solvate complexes in gas and in polar medium. The predominance of the 1-MeSaxPheq conformer in gas phase (1-Ph-eq :1-Ph-ax = 55:45, Delta G degrees = 0.13 kcal/mol) determined from GED is consistent with that measured in the freon solution by LT NMR (1-Ph-eq:1-Ph-ax = 65:35, Delta G degrees = 0.12 kcal/mol), the experimentally measured ratios being close to that estimated by quantum chemical calculations at both the DFT and MP2 levels of theory. (C) 2019 Elsevier Ltd. All rights reserved.}, language = {en} } @article{PoleschnerHeydenreich1995, author = {Poleschner, Helmut and Heydenreich, Matthias}, title = {13C NMR chemical shifts of unbranched 2-Alkyn-1-ols, w-Alkyn-1-ols and "internal" Alkyn-1-ols}, year = {1995}, language = {en} } @article{PoleschnerHeydenreichSchilde2000, author = {Poleschner, Helmut and Heydenreich, Matthias and Schilde, Uwe}, title = {13C, 19F and 77Se NMR study of vicinal (E)-fluoro(organylseleno)olefins and [(E)- fluoroalkenyl]diorganylselenonium salts}, year = {2000}, abstract = {Selenides of the type R1Se-EMe3 (E = Si, Ge, Sn, Pb) react with xenon difluoride by cleavage of the Se-E bond to yield the R1Se-F intermediate and the fluorides Me3E-F, whereas the Se-C bond in PhSe-tBu (E = C) is stable against XeF2. The presence of R1Se-F intermediates is confirmed by addition to acetylenes (4-octyne, 3-hexyne). Thus, the fluoroselenenylation of acetylenes gives fluoro(organylseleno)olefins in preparative yields. In the cases of E = Si, Ge, Sn, and Pb, aryl and n-alkyl groups are suitable as the substituent R1. The X-ray crystal structural analysis of (E)-3- (p-carboxyphenylseleno)-4-fluorohex-3-ene - the first example of an uncharged fluoroselenoolefin synthesized from p- EtO2C-C6H4-Se-SnMe3, XeF2, and 3-hexyne followed by an ester hydrolysis - shows that the addition of the selenenylfluoride intermediate to the acetylene proceeds via a trans-addition, as is known for the R2Se2-XeF2 reagents.}, language = {en} } @article{PoleschnerHeydenreich1997, author = {Poleschner, Helmut and Heydenreich, Matthias}, title = {1H and 13C NMR Spectra and One-Bond 13C,13C Coupling Constants of 2-Alken-4-yn-1-ols, (E)-2-Alken-4-yn-1-yl Acetates and (E)-2-Alken-4-yn-1-als}, year = {1997}, language = {en} } @article{MutaiHeydenreichThoithietal.2013, author = {Mutai, Peggoty and Heydenreich, Matthias and Thoithi, Grace and Mugumbate, Grace and Chibale, Kelly and Yenesew, Abiy}, title = {3-Hydroxyisoflavanones from the stem bark of dalbergia melanoxylon - isolation, antimycobacterial evaluation and molecular docking studies}, series = {Phytochemistry letters}, volume = {6}, journal = {Phytochemistry letters}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2013.08.018}, pages = {671 -- 675}, year = {2013}, abstract = {Two new 3-hydroxyisoflavanones, (S)-3,4',5-trihydroxy-2',7-dimethoxy-3'-prenylisoflavanone (trivial name kenusanone F 7-methyl ether) and (S)-3,5-dihydroxy-2',7-dimethoxy-2 '',2 ''-dimethylpyrano[5 '',6 '':3',4']isoflavanone (trivial name sophoronol-7-methyl ether) along with two known compounds (dalbergin and formononetin) were isolated from the stem bark of Dalbergia melanoxylon. The structures were elucidated using spectroscopic techniques. Kenusanone F 7-methyl ether showed activity against Mycobacterium tuberculosis, whereas both of the new compounds were inactive against the malaria parasite Plasmodium falciparum at 10 mu g/ml. Docking studies showed that the new compounds kenusanone F 7-methyl ether and sophoronol-7-methyl ether have high affinity for the M. tuberculosis drug target INHA.}, language = {en} } @article{AtilawHeydenreichNdakalaetal.2014, author = {Atilaw, Yoseph and Heydenreich, Matthias and Ndakala, Albert and Akala, Hoseah M. and Kamau, Edwin and Yenesew, Abiy}, title = {3-Oxo-14 alpha, 15 alpha-epoxyschizozygine: A new schizozygane indoline alkaloid from Schizozygia coffaeoides}, series = {Phytochemistry letters}, volume = {10}, journal = {Phytochemistry letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2014.07.003}, pages = {28 -- 31}, year = {2014}, abstract = {The stem bark extract of Schizozygia coffaeoides (Apocynaceae) showed moderate antiplasmodial activity (IC50 = 8-12 mu g/mL) against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the extract led to the isolation of a new schizozygane indoline alkaloid, named 3-oxo-14 alpha, 15 alpha-epoxyschizozygine. In addition, two dimeric anthraquinones, cassiamin A and cassiamin B, were identified for the first time in the family Apocynaceae. The structures of the isolated compounds were deduced on the basis of spectroscopic evidence. The schizozygane indole alkaloids showed good to moderate antiplasmodial activities (IC50 = 13-52 mu m). (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.}, language = {en} } @article{DereseBarasaAkalaetal.2014, author = {Derese, Solomon and Barasa, Leonard and Akala, Hoseah M. and Yusuf, Amir O. and Kamau, Edwin and Heydenreich, Matthias and Yenesew, Abiy}, title = {4 '-Prenyloxyderrone from the stem bark of Millettia oblata ssp teitensis and the antiplasmodial activities of isoflavones from some Millettia species}, series = {Phytochemistry letters}, volume = {8}, journal = {Phytochemistry letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2014.02.001}, pages = {69 -- 72}, year = {2014}, abstract = {The CH2Cl2/MeOH (1: 1) extract of the stem bark of Millettia oblata ssp. teitensis showed antiplasmodial activity (IC50 = 10-12 mu g/mL) against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the extract led to the isolation of a new isoflavone, 4'-prenyloxyderrone (1), together with known isoflavones (8-O-methylretusin, durmillone, maximaisoflavone B, maximaisoflavone H and maximaisoflavone J), a rotenoid (tephrosin) and a triterpene (lupeol). Similar investigation of Millettia leucantha resulted in the identification of the isoflavones afrormosin and wistin, and the flavone chrysin. The identification of these compounds was based on their spectroscopic data. Five of the isoflavones isolated from these plants as well as 11 previously reported compounds from Millettia dura were tested and showed good to moderate antiplasmodial activities (IC50 = 13-53 mu M), with the new compound, 4'-prenyloxyderrone, being the most active (IC50 = 13-15 mu M).}, language = {en} } @article{MuivaMutisyaMachariaHeydenreichetal.2014, author = {Muiva-Mutisya, Lois and Macharia, Bernard and Heydenreich, Matthias and Koch, Andreas and Akala, Hoseah M. and Derese, Solomon and Omosa, Leonidah K. and Yusuf, Amir O. and Kamau, Edwin and Yenesew, Abiy}, title = {6 alpha-Hydroxy-alpha-toxicarol and (+)-tephrodin with antiplasmodial activities from Tephrosia species}, series = {Phytochemistry letters}, volume = {10}, journal = {Phytochemistry letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2014.09.002}, pages = {179 -- 183}, year = {2014}, abstract = {The CH2Cl2/MeOH (1: 1) extract of the roots of Tephrosia villosa showed good antiplasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of 3.1 +/- 0.4 and 1.3 +/- 0.3 mu g/mL, respectively. Chromatographic separation of the extract yielded a new rotenoid, 6 alpha-hydroxy-alpha-toxicarol, along with five known rotenoids, (rotenone, deguelin, sumatrol, 12 alpha-hydroxy-alpha-toxicarol and villosinol). Similar treatment of the extract of the stem of Tephrosia purpurea (IC50 = 4.1 +/- 0.4 and 1.9 +/- 0.2 mu g/mL against D6 and W2 strains of P. falciparum, respectively) yielded a new flavone having a unique substituent at C-7/C-8 [trivial name (+)-tephrodin], along with the known flavonoids tachrosin, obovatin methyl ether and derrone. The relative configuration and the most stable conformation in (+)-tephrodin was determined by NMR and theoretical energy calculations. The rotenoids and flavones tested showed good to moderate antiplasmodial activities (IC50 = 9 +/- 23 mu M). Whereas the cytotoxicity of rotenoids is known, the flavones (+)-tephrodin and tachrosin did not show significant cytotoxicity (IC50 > 100 mu M;) against mammalian African monkey kidney (vero) and human larynx carcinoma (HEp2) cell lines. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.}, language = {en} } @article{YenesewMushibeIndulietal.2005, author = {Yenesew, Abiy and Mushibe, E. K. and Induli, M. and Derese, Solomon and Midiwo, Jacob O. and Kabaru, Jacques M. and Heydenreich, Matthias and Koch, Andreas and Peter, Martin G.}, title = {7a-O-methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoloata}, issn = {0031-9422}, year = {2005}, abstract = {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}, language = {en} } @article{YenesewTwinomuhweziKiremireetal.2009, author = {Yenesew, Abiy and Twinomuhwezi, Hannington and Kiremire, Bernard T. and Mbugua, Martin N. and Gitu, Peter M. and Heydenreich, Matthias and Peter, Martin G.}, title = {8-Methoxyneorautenol and radical scavenging flavonoids from Erythrina abyssinica}, issn = {1011-3924}, year = {2009}, abstract = {A new pterocarpan (named 8-methoxyneorautenol) was isolated from the acetone ext. of the root bark of Erythrina abyssinica. In addn., the known isoflavonoid derivs. eryvarin L, erycristagallin and shinpterocarpin were identified for the first time from the roots of this plant. The structures were detd. on the basis of spectroscopic evidence. The new compd. showed selective antimicrobial activity against Trichophyton mentagrophytes. The acetone ext. of the root bark of E. abyssinica showed radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The pterocarpenes, 3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene and erycristagallin, were the most active constituents of the roots of this plant and showing dose-dependent activities similar to that of the std. quercetin. [on SciFinder (R)]}, language = {en} } @article{BuyinzaDereseNdakalaetal.2021, author = {Buyinza, Daniel and Derese, Solomon and Ndakala, Albert and Heydenreich, Matthias and Yenesew, Abiy and Koch, Andreas and Oriko, Richard}, title = {A coumestan and a coumaronochromone from Millettia lasiantha}, series = {Biochemical systematics and ecology}, volume = {97}, journal = {Biochemical systematics and ecology}, publisher = {Elsevier}, address = {Oxford}, issn = {0305-1978}, doi = {10.1016/j.bse.2021.104277}, pages = {5}, year = {2021}, abstract = {The manuscript describes the phytochemical investigation of the roots, leaves and stem bark of Millettia lasiantha resulting in the isolation of twelve compounds including two new isomeric isoflavones lascoumestan and las-coumaronochromone. The structures of the new compounds were determined using different spectroscopic techniques.}, language = {en} } @article{AkampuriraAkalaDereseetal.2023, author = {Akampurira, Denis and Akala, Hoseah M. and Derese, Solomon and Heydenreich, Matthias and Yenesew, Abiy}, title = {A new C-C linked benzophenathridine-2-quinoline dimer, and the antiplasmodial activity of alkaloids from Zanthoxylum holstzianum}, series = {Natural product research}, volume = {37}, journal = {Natural product research}, number = {13}, publisher = {Taylor \& Francis}, address = {London [u.a.]}, issn = {1478-6419}, doi = {10.1080/14786419.2022.2034810}, pages = {2161 -- 2171}, year = {2023}, abstract = {The CH2Cl2/MeOH (1:1) extract of Zanthoxylum holstzianum stem bark showed good antiplasmodial activity (IC50 2.5 +/- 0.3 and 2.6 +/- 0.3 mu g/mL against the W2 and D6 strains of Plasmodium falciparum, respectively). From the extract five benzophenanthridine alkaloids [8-acetonyldihydrochelerythrine (1), nitidine (2), dihydrochelerythine (3), norchelerythrine (5), arnottianamide (8)]; a 2-quinolone alkaloid [N-methylflindersine (4)]; a lignan [4,4 '-dihydroxy-3,3 '-dimethoxylignan-9,9 '-diyl diacetate (7)] and a dimer of a benzophenanthridine and 2-quinoline [holstzianoquinoline (6)] were isolated. The CH2Cl2/MeOH (1:1) extract of the root bark afforded 1, 3-6, 8, chelerythridimerine (9) and 9-demethyloxychelerythrine (10). Holstzianoquinoline (6) is new, and is the second dimer linked by a C-C bond of a benzophenanthridine and a 2-quinoline reported thus far. The compounds were identified based on spectroscopic evidence. Amongst five compounds (1-5) tested against two strains of P. falciparum, nitidine (IC50 0.11 +/- 0.01 mu g/mL against W2 and D6 strains) and norchelerythrine (IC50 value of 0.15 +/- 0.01 mu g/mL against D6 strain) were the most active.}, language = {en} } @phdthesis{DereseYenesewMidiwoetal.2003, author = {Derese, Solomon and Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G.}, title = {A new isoflavone from stem bark of Millettia dura}, issn = {1011-3924}, year = {2003}, language = {en} } @article{AbdissaHeydenreichMidiwoetal.2014, author = {Abdissa, Negera and Heydenreich, Matthias and Midiwo, Jacob O. and Ndakala, Albert and Majer, Zsuzsanna and Neumann, Beate and Stammler, Hans-Georg and Sewald, Norbert and Yenesew, Abiy}, title = {A xanthone and a phenylanthraquinone from the roots of Bulbine frutescens, and the revision of six seco-anthraquinones into xanthones}, series = {Phytochemistry letters}, volume = {9}, journal = {Phytochemistry letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2014.04.004}, pages = {67 -- 73}, year = {2014}, abstract = {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.}, language = {en} } @article{YaoubaKochGuantaietal.2018, author = {Yaouba, Souaibou and Koch, Andreas and Guantai, Eric M. and Derese, Solomon and Irungu, Beatrice and Heydenreich, Matthias and Yenesew, Abiy}, title = {Alkenyl cyclohexanone derivatives from Lannea rivae and Lannea schweinfurthii}, series = {Phytochemistry letters / Phytochemical Society of Europe}, volume = {23}, journal = {Phytochemistry letters / Phytochemical Society of Europe}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2017.12.001}, pages = {141 -- 148}, year = {2018}, abstract = {Phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Lannea rivae (Chiov) Sacleux (Anacardiaceae) led to the isolation of a new alkenyl cyclohexenone derivative: (4R,6S)-4,6-dihydroxy-6-((Z)-nonadec-14′-en-1-yl)cyclohex-2-en-1-one (1), and a new alkenyl cyclohexanol derivative: (2S*,4R*,5S*)-2,4,5-trihydroxy-2-((Z)-nonadec-14′-en-1-yl)cyclohexanone (2) along with four known compounds, namely epicatechin gallate, taraxerol, taraxerone and β-sitosterol; while the stem bark afforded two known compounds, daucosterol and lupeol. Similar investigation of the roots of Lannea schweinfurthii (Engl.) Engl. led to the isolation of four known compounds: 3-((E)-nonadec-16′-enyl)phenol, 1-((E)-heptadec-14′-enyl)cyclohex-4-ene-1,3-diol, catechin, and 1-((E)-pentadec-12′-enyl)cyclohex-4-ene-1,3-diol. The structures of the isolated compounds were determined by NMR spectroscopy and mass spectrometry. The absolute configuration of compound 1 was established by quantum chemical ECD calculations. In an antibacterial activity assay using the microbroth kinetic method, compound 1 showed moderate activity against Escherichia coli while compound 2 exhibited moderate activity against Staphylococcus aureus. Compound 1 also showed moderate activity against E. coli using the disc diffusion method. The roots extract of L. rivae was notably cytotoxic against both the DU-145 prostate cancer cell line and the Vero mammalian cell line (CC50 = 5.24 and 5.20 μg/mL, respectively). Compound 1 was also strongly cytotoxic against the DU-145 cell line (CC50 = 0.55 μg/mL) but showed no observable cytotoxicity (CC50 > 100 μg/mL) against the Vero cell line. The roots extract of L. rivae and L. schweinfurthii, epicatechin gallate as well as compound 1 exhibited inhibition of carageenan-induced inflammation.}, language = {en} } @article{BoehmerDoerrenbaecherFringsetal.1996, author = {B{\"o}hmer, Volker and D{\"o}rrenb{\"a}cher, Ralph and Frings, Michael and Heydenreich, Matthias and DePaoli, Diana and Vogt, Walter and Ferguson, George and Thondorf, Iris}, title = {Annelated calixarenes composed of Calix[4]arenes with hydroxy groups in the endo and exo position}, year = {1996}, language = {en} } @article{KihampaNkunyaJosephetal.2009, author = {Kihampa, Charles and Nkunya, Mayunga H. H. and Joseph, Cosam C. and Magesa, Stephen M. and Hassanali, Ahmed and Heydenreich, Matthias and Kleinpeter, Erich}, title = {Anti-mosquito and antimicrobial nor-halimanoids, isocoumarins and an anilinoid from Tessmannia densiflora}, issn = {0031-9422}, doi = {10.1016/j.phytochem.2009.07.024}, year = {2009}, abstract = {The nor-halimane diterpenoid tessmannic acid and its methyl, 2-methylisopropyl and 1-methylbutyl esters, the unusual isocoumarins 8-hydroxy-6-methoxy-3-pentylisocoumarin and 7-chloro-8-hydroxy-6-methoxy-3-pentylisocoumarin, and 5- pentyl-3-methoxy-N-butylaniline were isolated from the stem and root bark extracts of Tessmannia densiflora Harms (Caesalpiniaceae) that showed mosquito larvicidal activity. The structures were determined on interpretation of spectroscopic data. Tessmannic acid and its methyl ester exhibited antibacterial and antifungal activity. The compounds also caused high larvae and adult Anopheles gambiae mosquitoe mortality effects, and stronger mosquito repellency than that shown by the standard repellent DEET, hence indicating Tessmannia species to be potential sources of bioactive natural products.}, language = {en} } @article{SelemaniNondoMoshietal.2017, author = {Selemani, Ramadhani Selemani Omari and Nondo, Omari and Moshi, Mainen Julius and Erasto, Paul and Masimba, Pax Jessey and Machumi, Francis and Kidukuli, Abdul Waziri and Heydenreich, Matthias and Zofou, Denis}, title = {Anti-plasmodial activity of Norcaesalpin D and extracts of four medicinal plants used traditionally for treatment of malaria}, series = {BMC Complementary and Alternative Medicine volume}, volume = {17}, journal = {BMC Complementary and Alternative Medicine volume}, publisher = {BioMed Central}, address = {London}, issn = {1472-6882}, doi = {10.1186/s12906-017-1673-8}, pages = {8}, year = {2017}, abstract = {Background: Malaria is an old life-threatening parasitic disease that is still affecting many people, mainly children living in sub-Saharan Africa. Availability of effective antimalarial drugs played a significant role in the treatment and control of malaria. However, recent information on the emergence of P. falciparum parasites resistant to one of the artemisinin-based combination therapies suggests the need for discovery of new drug molecules. Therefore, this study aimed to evaluate the antiplasmodial activity of extracts, fractions and isolated compound from medicinal plants traditionally used in the treatment of malaria in Tanzania. Methods: Dry powdered plant materials were extracted by cold macerations using different solvents. Norcaesalpin D was isolated by column chromatography from dichloromethane root extract of Caesalpinia bonducella and its structure was assigned based on the spectral data. Crude extracts, fractions and isolated compound were evaluated for antiplasmodial activity against chloroquine-sensitive P. falciparum (3D7), chloroquine-resistant P. falciparum (Dd2, K1) and artemisinin-resistant P. falciparum (IPC 5202 Battambang, IPC 4912 Mondolkiri) strains using the parasite lactate dehydrogenase assay. Results: The results indicated that extracts of Erythrina schliebenii, Holarrhena pubescens, Dissotis melleri and C. bonducella exhibited antiplasmodial activity against Dd2 parasites. Ethanolic root extract of E. schliebenii had an IC50 of 1.87 mu g/mL while methanolic and ethanolic root extracts of H. pubescens exhibited an IC50 = 2.05 mu g/mL and IC50 = 2.43 mu g/mL, respectively. Fractions from H. pubescens and C. bonducella roots were found to be highly active against K1, Dd2 and artemisinin-resistant parasites. Norcaesalpin D from C. bonducella root extract was active with IC50 of 0.98, 1.85 and 2.13 mu g/mL against 3D7, Dd2 and IPC 4912-Mondolkiri parasites, respectively. Conclusions: Antiplasmodial activity of norcaesalpin D and extracts of E. schliebenii, H. pubescens, D. melleri and C. bonducella reported in this study requires further attention for the discovery of antimalarial lead compounds for future drug development.}, language = {en} } @article{YenesewInduliDereseetal.2004, author = {Yenesew, Abiy and Induli, M. and Derese, Solomon and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G. and Akala, Hoseah M. and Wangui, Julia and Liyala, Pamela and Waters, Norman C.}, title = {Anti-plasmodial flavonoids from the stem bark of Erythrina abyssinica}, issn = {0031-9422}, year = {2004}, abstract = {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}, language = {en} } @article{BarazaNeserJacksonetal.2016, author = {Baraza, Lilechi D. and Neser, Wekesa and Jackson, Korir Cheruiyot and Fredrick, Juma B. and Dennis, Ochieno and Wairimu, Kamau R. and Keya, Aggrey Osogo and Heydenreich, Matthias}, title = {Antimicrobial Coumarins from the Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes), from Kenya}, series = {International journal of medicinal mushrooms}, volume = {18}, journal = {International journal of medicinal mushrooms}, publisher = {Begell House}, address = {Danbury}, issn = {1521-9437}, doi = {10.1615/IntJMedMushrooms.v18.i10.60}, pages = {905 -- 913}, year = {2016}, abstract = {Pleurotus ostreatus has been widely used as food because of its nutritional and medicinal properties. These have been attributed to the presence of macronutrients, minerals, vitamins, and amino acids, among other secondary metabolites. There are, however, few reports on the antimicrobial activities of different classes of purified compounds from P. ostreatus. This led to the current study, the objective of which was to chemically characterize the antibiotic activities of P. ()streams against selected human pathogenic bacteria and endophytic fungi. Chemical structures were determined using spectroscopic methods and by comparison with values of related structures reported in the literature. Pure compounds from P. ostreatus were tested in vitro against pathogenic bacteria (Staphylococcus aureus and Escherichia coli) and endophytic fungi (Pencillium digitatum and Fusarium prolferatum). A new compound, (E)-5,7-dimethoxy-6-(3-methylbuta-1,3-dienyl)-2H-chromen-2-one (5-methoxy-(E)-suberodiene) (compound 2), along with ergosterol (compound I.) and 5,7-dimethoxy-6-(3-methylbut-2-enyl)-2H-chromen-2-one (toddaculin; compound 3), were isolated from the fruiting bodies of P. ostreatus. The growth of S. aureus,E proliferatum, and P. digitatum colonies was inhibited in media containing compound 2, with minimum inhibitory concentrations closely comparable to those of conventional antibiotics.}, language = {en} } @article{OmosaAmuguneNdundaetal.2014, author = {Omosa, Leonidah K. and Amugune, Beatrice and Ndunda, Beth and Milugo, Trizah K. and Heydenreich, Matthias and Yenesew, Abiy and Midiwo, Jacob O.}, title = {Antimicrobial flavonoids and diterpenoids from Dodonaea angustifolia}, series = {South African journal of botany : an international interdisciplinary journal for botanical sciences}, volume = {91}, journal = {South African journal of botany : an international interdisciplinary journal for botanical sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0254-6299}, doi = {10.1016/j.sajb.2013.11.012}, pages = {58 -- 62}, year = {2014}, language = {en} } @article{YenesewDereseMidiwoetal.2005, author = {Yenesew, Abiy and Derese, Solomon and Midiwo, Jacob O. and Bii, Christine C. and Heydenreich, Matthias and Peter, Martin G.}, title = {Antimicrobial flavonoids from the stem bark of Erythrina burttii}, issn = {0367-326X}, year = {2005}, abstract = {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}, language = {en} } @article{KihampaNkunyaJosephetal.2010, author = {Kihampa, Charles and Nkunya, Mayunga H. H. and Joseph, Cosam C. and Magesa, Stephen M. and Hassanali, Ahmed and Heydenreich, Matthias and Kleinpeter, Erich}, title = {Antimosquito and antimicrobial clerodanoids and a chlorobenzoid from Tessmannia species}, issn = {1934-578X}, year = {2010}, abstract = {The clerodane diterpenoids trans-kolavenolic acid, 18-oxocleroda-3,13(E)-dien-15-oic acid, ent-(18- hydroxycarbonyl)-cleroda- 3,13(E)-dien-15-oate, 2-oxo-ent-cleroda-3,13(Z)-dien-15-oic acid and trans-2-oxo-ent-cleroda- 13(Z)-en-15-oic acid, and the chlorobenzenoid O-(3-hydroxy-4-hydroxycarbonyl-5-pentylphenyl)-3-chloro-4-methoxy-6-pentyl- 2-oxybenzoic acid were isolated from Tessmannia martiniana var pauloi and T. martiniana var matiniana. Structures were established based on interpretation of spectroscopic data. Some of the compounds exhibited significant antimosquito, antifungal and antibacterial activities.}, language = {en} } @article{OloyaNamukobeHeydenreichetal.2021, author = {Oloya, Benson and Namukobe, Jane and Heydenreich, Matthias and Ssengooba, Willy and Schmidt, Bernd and Byamukama, Robert}, title = {Antimycobacterial activity of the extract and isolated compounds from the stem bark of Zanthoxylum leprieurii Guill. and Perr.}, series = {Natural product communications : an international journal for communications and reviews}, volume = {16}, journal = {Natural product communications : an international journal for communications and reviews}, number = {8}, publisher = {Sage Publ.}, address = {Thousand Oaks}, issn = {1934-578X}, doi = {10.1177/1934578X211035851}, pages = {8}, year = {2021}, abstract = {Zanthoxylum leprieurii Guill. and Perr. (Rutaceae) stem bark is used locally in Uganda for treating tuberculosis (TB) and cough-related infections. Lupeol (1), sesamin (2), trans-fagaramide (3), arnottianamide (4), (S)-marmesinin (5), and hesperidin (6) were isolated from the chloroform/methanol (1:1) extract of Z. leprieurii stem bark. Their structures were elucidated using spectroscopic techniques and by comparison with literature data. Furthermore, the extract and isolated compounds were subjected to antimycobacterial activity. The extract exhibited moderate activity against the susceptible (H(37)Rv) TB strain, but weak activity against the multidrug resistant (MDR)-TB strain with minimum inhibitory concentrations (MICs) of 586.0 and 1172.0 mu g/mL, respectively. Compound 3 (trans-fagaramide) showed significant antimycobacterial activity against the susceptible (H(37)Rv) TB strain (MIC 6 mu g/mL), but moderate activity against the MDR-TB strain (MIC 12.2 mu g/mL). Compounds 2, 5, 6, and 1 showed moderate activities against the susceptible (H(37)Rv) strain (MIC 12.2-98.0 mu g/mL) and moderate to weak activities against the MDR-TB strain (MIC 24.4-195.0 mu g/mL). This study reports for the first time the isolation of compounds 1 to 6 from the stem bark of Z leprieurii. trans-Fagaramide (3) may present a vital template in pursuit of novel and highly effective TB drugs.}, language = {en} } @inproceedings{MachumiYenesewMidiwoetal.2012, author = {Machumi, F. and Yenesew, Abiy and Midiwo, J. O. and Heydenreich, Matthias and Kleinpeter, Erich and Khan, S. and Tekwani, B. L. and Walker, L. A. and Muhammad, I}, title = {Antiparasitic and anticancer carvotacetone derivatives from Sphaeranthus bullatus}, series = {Planta medica : journal of medicinal plant and natural product research}, volume = {78}, booktitle = {Planta medica : journal of medicinal plant and natural product research}, number = {11}, publisher = {Thieme}, address = {Stuttgart}, issn = {0032-0943}, pages = {1201 -- 1202}, year = {2012}, language = {en} } @article{MachumiYenesewMidiwoetal.2012, author = {Machumi, Francis and Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Kleinpeter, Erich and Tekwani, Babu L. and Khan, Shabana I. and Walker, Larry A. and Muhammad, Ilias}, title = {Antiparasitic and anticancer carvotacetone derivatives of Sphaeranthus bullatus}, series = {Natural product communications : an international journal for communications and reviews}, volume = {7}, journal = {Natural product communications : an international journal for communications and reviews}, number = {9}, publisher = {NPC}, address = {Westerville}, issn = {1934-578X}, pages = {1123 -- 1126}, year = {2012}, abstract = {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.}, language = {en} } @article{KeruboMidiwoDereseetal.2013, author = {Kerubo, Leonidah Omosa and Midiwo, Jacob Ogweno and Derese, Solomon and Langat, Moses K. and Akala, Hoseah M. and Waters, Norman C. and Peter, Martin and Heydenreich, Matthias}, title = {Antiplasmodial activity of compounds from the surface exudates of senecio roseiflorus}, series = {Natural product communications : an international journal for communications and reviews}, volume = {8}, journal = {Natural product communications : an international journal for communications and reviews}, number = {2}, publisher = {NPC}, address = {Westerville}, issn = {1934-578X}, pages = {175 -- 176}, year = {2013}, abstract = {From the surface exudates of Senecio roseiflorus fourteen known methylated flavonoids and one phenol were isolated and characterized. The structures of these compounds were determined on the basis of their spectroscopic analysis. The surface exudate and the flavonoids isolated showed moderate to good antiplasmodial activity with 5,4'-dihydroxy-7-dimethoxyflavanone having the highest activity against chloroquine-sensitive (D6) and resistant (W2) strains of Plasmodium falciparum, with IC50 values of 3.2 +/- 0.8 and 4.4 +/- 0.01 mu g/mL respectively.}, language = {en} } @article{ChepkiruiOchiengSarkaretal.2020, author = {Chepkirui, Carolyne and Ochieng, Purity J. and Sarkar, Biswajyoti and Hussain, Aabid and Pal, Chiranjib and Yang, Li Jun and Coghi, Paolo and Akala, Hoseah M. and Derese, Solomon and Ndakala, Albert and Heydenreich, Matthias and Wong, Vincent K. W. and Erdelyi, Mate and Yenesew, Abiy}, title = {Antiplasmodial and antileishmanial flavonoids from Mundulea sericea}, series = {Fitoterapia}, volume = {149}, journal = {Fitoterapia}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0367-326X}, doi = {10.1016/j.fitote.2020.104796}, pages = {6}, year = {2020}, abstract = {Five known compounds (1-5) were isolated from the extract of Mundulea sericea leaves. Similar investigation of the roots of this plant afforded an additional three known compounds (6-8). The structures were elucidated using NMR spectroscopic and mass spectrometric analyses. The absolute configuration of 1 was established using ECD spectroscopy. In an antiplasmodial activity assay, compound 1 showed good activity with an IC50 of 2.0 mu M against chloroquine-resistant W2, and 6.6 mu M against the chloroquine-sensitive 3D7 strains of Plasmodium falciparum. Some of the compounds were also tested for antileishmanial activity. Dehydrolupinifolinol (2) and sericetin (5) were active against drug-sensitive Leishmania donovani (MHOM/IN/83/AG83) with IC50 values of 9.0 and 5.0 mu M, respectively. In a cytotoxicity assay, lupinifolin (3) showed significant activity on BEAS-2B (IC50 4.9 mu M) and HePG2 (IC50 10.8 mu M) human cell lines. All the other compounds showed low cytotoxicity (IC50 > 30 mu M) against human lung adenocarcinoma cells (A549), human liver cancer cells (HepG2), lung/bronchus cells (epithelial virus transformed) (BEAS-2B) and immortal human hepatocytes (LO2)}, language = {en} } @article{IrunguAdipoOrwaetal.2015, author = {Irungu, Beatrice N. and Adipo, Nicholas and Orwa, Jennifer A. and Kimani, Francis and Heydenreich, Matthias and Midiwo, Jacob O. and Bjoremark, Per Martin and Hakansson, Mikael and Yenesew, Abiy and Erdelyi, Mate}, title = {Antiplasmodial and cytotoxic activities of the constituents of Turraea robusta and Turraea nilotica}, series = {Journal of ethnopharmacology : an interdisciplinary journal devoted to bioscientific research on indigenous drugs}, volume = {174}, journal = {Journal of ethnopharmacology : an interdisciplinary journal devoted to bioscientific research on indigenous drugs}, publisher = {Elsevier}, address = {Clare}, issn = {0378-8741}, doi = {10.1016/j.jep.2015.08.039}, pages = {419 -- 425}, year = {2015}, abstract = {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.}, language = {en} } @misc{PeterYenesewTwinomuhwezietal.2009, author = {Peter, Martin G. and Yenesew, Abiy and Twinomuhwezi, Hannington and Kabaru, Jacques M. and Akala, Hoseah M. and Kiremire, Bernard T. and Heydenreich, Matthias and Eyase, Fredrick and Waters, Norman C. and Walsh, Douglas S.}, title = {Antiplasmodial and larvicidal flavonoids from Derris trifoliata}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44614}, year = {2009}, abstract = {From the dichloromethane-methanol (1:1) extract of the seed pods of Derris trifoliata, a new flavanone derivative (S)-lupinifolin 4´-methyl ether was isolated. In addition, the known flavonoids lupinifolin and rotenone were identified. The structures were determined on the basis of spectroscopic evidence. Lupinfolin showed moderate in vitro antiplasmodial activity against the D6 (chloroquine-sensitive) and W2 (chloroquineresistant) strains of Plasmodium falciparum. The different parts of this plant showed larvicidal activities against Aedes aegypti and rotenoids were identified as the active principles.}, language = {en} } @article{AndayiYenesewDereseetal.2006, author = {Andayi, Andrew W. and Yenesew, Abiy and Derese, Solomon and Midiwo, Jacob O. and Gitu, Peter M. and Jondiko, Ogoche J. I. and Akala, Hoseah M. and Liyala, Pamela and Wangui, Julia and Waters, Norman C. and Heydenreich, Matthias and Peter, Martin G.}, title = {Antiplasmodial flavonoids from Erythrina sacleuxii}, issn = {0032-0943}, doi = {10.1055/s-2005-873200}, year = {2006}, abstract = {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}, language = {en} } @article{MuivaMutisyaAtilawHeydenreichetal.2018, author = {Muiva-Mutisya, Lois M. and Atilaw, Yoseph and Heydenreich, Matthias and Koch, Andreas and Akala, Hoseah M. and Cheruiyot, Agnes C. and Brown, Matthew L. and Irungu, Beatrice and Okalebo, Faith A. and Derese, Solomon and Mutai, Charles and Yenesew, Abiy}, title = {Antiplasmodial prenylated flavanonols from Tephrosia subtriflora}, series = {Natural Product Research}, volume = {32}, journal = {Natural Product Research}, number = {12}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {1478-6419}, doi = {10.1080/14786419.2017.1353510}, pages = {1407 -- 1414}, year = {2018}, abstract = {The CH2Cl2/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodiumfalciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC50 values 1.4-4.6M without significant cytotoxicity against Vero and HEp2 cell lines (IC50>100M). The new compound (1) showed weak antiplasmodial activity, IC50 12.5-24.2M, but also showed selective anticancer activity against HEp2 cell line (CC50 16.9M). [GRAPHICS] .}, language = {en} } @misc{PeterMuivaYenesewetal.2009, author = {Peter, Martin G. and Muiva, Lois M. and Yenesew, Abiy and Derese, Solomon and Heydenreich, Matthias and Akala, Hoseah M. and Eyase, Fredrick and Waters, Norman C. and Mutai, Charles and Keriko, Joseph M. and Walsh, Douglas S.}, title = {Antiplasmodial β-hydroxydihydrochalcone from seedpods of Tephrosia elata}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-44437}, year = {2009}, abstract = {From the seedpods of Tephrosia elata, a new β-hydroxydihydrochalcone named (S)-elatadihydrochalcone was isolated. In addition, the known flavonoids obovatachalcone, obovatin, obovatin methyl ether and deguelin were identified. The structures were determined on the basis of spectroscopic evidence. The crude extract and the flavonoids obtained from the seedpods of this plant showed antiplasmodial activities. The literature NMR data on β-hydroxydihydrochalcones is reviewed and the identity of some of the compounds assigned β-hydroxydihydrochalcone skeleton is questioned.}, language = {en} } @article{MuthauraKerikoMutaietal.2017, author = {Muthaura, Charles N. and Keriko, Joseph M. and Mutai, Charles and Yenesew, Abiy and Heydenreich, Matthias and Atilaw, Yoseph and Gathirwa, Jeremiah W. and Irungu, Beatrice N. and Derese, Solomon}, title = {Antiplasmodial, cytotoxicity and phytochemical constituents of four maytenus species used in traditional medicine in Kenya}, series = {The natural products journal}, volume = {7}, journal = {The natural products journal}, number = {2}, publisher = {Bentham Science Publ.}, address = {Sharjah}, issn = {2210-3155}, doi = {10.2174/2210315507666161206144050}, pages = {144 -- 152}, year = {2017}, abstract = {Background: In Kenya, several species of the genus Maytenus are used in traditional medicine to treat many diseases including malaria. In this study, phytochemical constituents and extracts of Maytenus undata, M. putterlickioides, M. senegalensis and M. heterophylla were evaluated to determine compound/s responsible for antimalarial activity. Objective: To isolate antiplasmodial compounds from these plant species which could be used as marker compounds in the standardization of their extracts as a phytomedicine for malaria. Methods: Constituents were isolated through activity-guided fractionation of the MeOH/CHCl3 (1:1) extracts and in vitro inhibition of Plasmodium falciparum. Cytotoxicity was evaluated using Vero cells and the compounds were elucidated on the basis of NMR spectroscopy. Results: Fractionation of the extracts resulted in the isolation of ten known compounds. Compound 1 showed promising antiplasmodial activity with IC50, 3.63 and 3.95 ng/ml against chloroquine sensitive (D6) and resistant (W2) P. falciparum, respectively and moderate cytotoxicity (CC50, 37.5 ng/ml) against Vero E6 cells. The other compounds showed weak antiplasmodial (IC50 > 1.93 mu g/ml) and cytotoxic (CC50 > 39.52 mu g/ml) activities against P. falciparum and Vero E6 cells, respectively. Conclusion: (20 alpha)-3-hydroxy-2-oxo-24-nor-friedela-1(10),3,5,7-tetraen-carboxylic acid-(29)-methyl-ester (pristimerin) (1) was the most active marker and lead compound that warrants further investigation as a template for the development of new antimalarial drugs. Pristimerin is reported for the first time in M. putterlickioides. 3-Hydroxyolean-12-en-28-oic acid (oleanolic acid) (5), stigmast-5-en-3-ol (beta-sitosterol) (6), 3-oxo-28-friedelanoic acid (7), olean-12-en-3-ol (beta-amyrin) (8), lup-20(29)-en-3-ol (lupeol) (9) and lup-20(29)-en-3-one (lupenone) (10) are reported for the first time in M. undata.}, language = {en} } @article{KleinpeterHeydenreichShainyan2021, author = {Kleinpeter, Erich and Heydenreich, Matthias and Shainyan, Bagrat A.}, title = {At the experimental limit of the NMR conformational analysis}, series = {Organic letters}, volume = {23}, journal = {Organic letters}, number = {2}, publisher = {American Chemical Society}, address = {Washington}, issn = {1523-7060}, doi = {10.1021/acs.orglett.0c03878}, pages = {405 -- 409}, year = {2021}, abstract = {The low temperature (95 K) NMR study of 1-Ph-1-t-Bu-silacyclohexane (1) showed the conformational equilibrium to be extremely one-sided toward thePh(ax),t-Bueq conformer. The barrier to interconversion has been measured (4.2-4.6 kcal/mol) and the conformational equilibrium [Delta nu = 1990.64 ppm (Si-29), 618.9 ppm (C-13), 1-Ph-ax:1-Pheq = (95.6-96.6\%):(3.4-4.4\%), K = 25 +/- 3, Delta G degrees = -RT ln K = 0.58-0.63 kcal/mol] analyzed. The assignment and quantification of the NMR signals is supported by MP2 and DFT calculations.}, language = {en} } @article{MadaniAnghileriHeydenreichetal.2022, author = {Madani, Amiera and Anghileri, Lucia and Heydenreich, Matthias and M{\"o}ller, Heiko Michael and Pieber, Bartholom{\"a}us}, title = {Benzylic fluorination induced by a charge-transfer complex with a solvent-dependent selectivity switch}, series = {Organic letters / publ. by the American Chemical Society}, volume = {24}, journal = {Organic letters / publ. by the American Chemical Society}, number = {29}, publisher = {American Chemical Society}, address = {Washington}, issn = {1523-7060}, doi = {10.1021/acs.orglett.2c02050}, pages = {5376 -- 5380}, year = {2022}, abstract = {We present a divergent strategy for the fluorination of phenylacetic acid derivatives that is induced by a charge-transfer complex between Selectfluor and 4-(dimethylamino)pyridine. A comprehensive investigation of the conditions revealed a critical role of the solvent on the reaction outcome. In the presence of water, decarboxylative fluorination through a single-electron oxidation is dominant. Non-aqueous conditions result in the clean formation of alpha-fluoro-alpha-arylcarboxylic acids.}, language = {en} } @article{FotieNkengfackPeteretal.2004, author = {Fotie, J. and Nkengfack, A. E. and Peter, Martin G. and Heydenreich, Matthias and Fomum, Z. T.}, title = {Chemical constituents of the ethyl acetate extracts of the stem bark and fruits of Dichrostachys cinerea and the roots of Parkia bicolor}, issn = {1011-3924}, year = {2004}, abstract = {The antibacterial activities of ethyl acetate, methanol and aqueous extracts of the stem bark of Dichrostachys cinerea and the roots of Parkia bicolor have been evaluated. Ethyl acetate extracts have been investigated, studies that led to a series of known compounds, amongst which many are reported here for the very first time from both the species}, language = {en} } @article{TraegerKlamrothKellingetal.2012, author = {Tr{\"a}ger, Juliane and Klamroth, Tillmann and Kelling, Alexandra and Lubahn, Susanne and Cleve, Ernst and Mickler, Wulfhard and Heydenreich, Matthias and M{\"u}ller, Holger and Holdt, Hans-J{\"u}rgen}, title = {Complexation of Palladium(II) with unsaturated Dithioethers a systematic development of highly selective ligands for solvent extraction}, series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, journal = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, number = {14}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-1948}, doi = {10.1002/ejic.201101406}, pages = {2341 -- 2352}, year = {2012}, abstract = {There is a demand for new and robust PdII extractants due to growing recycling rates. Chelating dithioethers are promising substances for solvent extraction as they form stable square-planar complexes with PdII. We have modified unsaturated dithioethers, which are known to coordinate PdII, and adapted them to the requirements of industrial practice. The ligands are analogues of 1,2-dithioethene with varying electron-withdrawing backbones and polar end-groups. The crystal structures of several ligands and their palladium complexes were determined as well as their electro- and photochemical properties, complex stability and behaviour in solution. Solvent extraction experiments showed the superiority of some of our ligands over conventionally used extractants in terms of their very fast reaction rates. With highly selective 1,2-bis(2-methoxyethylthio)benzene (4) it is possible to extract PdII from a highly acidic medium in the presence of other base and palladium-group metals.}, language = {en} } @article{KleinpeterHeydenreichWolleretal.1998, author = {Kleinpeter, Erich and Heydenreich, Matthias and Woller, Jochen and Wolf, Gunter and Koch, Andreas and Kempter, Gerhard and Pihlaja, Kalevi}, title = {Configuration and stereodynamics of exo/endoisomeric push-pull alkenes of pentadiene structure}, year = {1998}, language = {en} } @article{HeydenreichKochRistauetal.1998, author = {Heydenreich, Matthias and Koch, Andreas and Ristau, Thomas and Knoll, Susanne and Heinicke, Jochen and Sieler, Joachim and Niemitz, Matthias and M{\"u}hlst{\"a}dt, Manfred and Kleinpeter, Erich}, title = {Conformational analysis of sulfur-containing heterocycles ; part I: synthesis and structural determination of diastereomerically pure 4,6-bis(phenoxymethyl)-1,2,5-trithiepanes}, year = {1998}, language = {en} } @article{ShainyanMoskalikHeydenreichetal.2014, author = {Shainyan, Bagrat A. and Moskalik, Mikhail Yu and Heydenreich, Matthias and Kleinpeter, Erich}, title = {Conformational equilibrium and dynamic behavior of bis-N-triflyl substituted 3,8-diazabicyclo[3.2.1]octane}, series = {Magnetic resonance in chemistry}, volume = {52}, journal = {Magnetic resonance in chemistry}, number = {8}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0749-1581}, doi = {10.1002/mrc.4086}, pages = {448 -- 452}, year = {2014}, abstract = {Restricted rotation about the N-S partial double bonds in a bis-N-triflyl substituted 3,8-diazabicyclo[3.2.1]octane derivative 1 has been frozen at low temperature (Delta G* = 11.6 kcal mol(-1)), and the existence of all four rotamers about the two N-S bonds, 3-in, 8-in, 3-in, 8-out, 3-out, 8-in, and 3-out, 8-out, respectively, proved experimentally by NMR spectroscopy and theoretically by DFT and MP2 calculations. Copyright (C) 2014 John Wiley \& Sons, Ltd.}, language = {en} } @article{AdemMbavengKueteetal.2019, author = {Adem, Fozia A. and Mbaveng, Armelle T. and Kuete, Victor and Heydenreich, Matthias and Ndakala, Albert and Irungu, Beatrice and Yenesew, Abiy and Efferth, Thomas}, title = {Cytotoxicity of isoflavones and biflavonoids from Ormocarpum kirkii towards multi-factorial drug resistant cancer}, series = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, volume = {58}, journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology}, publisher = {Elsevier}, address = {M{\"u}nchen}, issn = {0944-7113}, doi = {10.1016/j.phymed.2019.152853}, pages = {10}, year = {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. Methods: The cytotoxicity of compounds was determined based on the resazurin reduction assay. Caspases activation was evaluated using the caspase-Glo assay. Flow cytometry was used to analyze the cell cycle (propodium iodide (PI) staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP) (JC-1) and reactive oxygen species (ROS) (H2DCFH-DA). CCRF-CEM leukemia cells were used as model cells for mechanistic studies. Results: Compounds 1, 2 and 4 displayed IC50 values below 20 mu M towards CCRF-CEM and CEM/ADR5000 leukemia cells, and were further tested towards a panel of 7 carcinoma cells. The IC50 values of the compounds against carcinoma cells varied from 16.90 mu M (in resistant U87MG.Delta EGFR glioblastoma cells) to 48.67 mu M (against HepG2 hepatocarcinoma cells) for 1, from 7.85 mu M (in U87MG.Delta EGFR cells) to 14.44 mu M (in resistant MDA-MB231/BCRP breast adenocarcinoma cells) for 2, from 4.96 mu M (towards U87MG.Delta EGFRcells) to 7.76 mu M (against MDA-MB231/BCRP cells) for 4, and from 0.07 mu M (against MDA-MB231 cells) to 2.15 mu M (against HepG2 cells) for doxorubicin. Compounds 2 and 4 induced apoptosis in CCRF-CEM cells mediated by MMP alteration and increased ROS production. Conclusion: The present report indicates that isoflavones and biflavonoids from Ormocarpum kirkii are cytotoxic compounds with the potential of being exploited in cancer chemotherapy. Compounds 2 and 4 deserve further studies to develop new anticancer drugs to fight sensitive and resistant cancer cell lines.}, language = {en} } @article{AriasFeuerbachSchmidtetal.2018, author = {Arias, Hugo R. and Feuerbach, Dominik and Schmidt, Bernd and Heydenreich, Matthias and Paz, Cristian and Ortells, Marcelo O.}, title = {Drimane Sesquiterpenoids Noncompetitively Inhibit Human alpha 4 beta 2 Nicotinic Acetylcholine Receptors with Higher Potency Compared to Human alpha 3 beta 4 and alpha 7 Subtypes}, series = {Journal of natural products}, volume = {81}, journal = {Journal of natural products}, number = {4}, publisher = {American Chemical Society}, address = {Washington}, issn = {0163-3864}, doi = {10.1021/acs.jnatprod.7b00893}, pages = {811 -- 817}, year = {2018}, abstract = {The drimane sesquiterpenoids drimenin, cinnamolide, dendocarbin A, and polygodial were purified from the Canelo tree (Drimys winteri) and chemically characterized by spectroscopic methods. The pharmacological activity of these natural compounds were determined on hα4β2, hα3β4, and hα7 nicotinic acetylcholine receptors (AChRs) by Ca2+ influx measurements. The results established that drimane sesquiterpenoids inhibit AChRs with the following selectivity: hα4β2 > hα3β4 > hα7. In the case of hα4β2 AChRs, the following potency rank order was determined (IC50's in μM): drimenin (0.97 ± 0.35) > cinnamolide (1.57 ± 0.36) > polygodial (62.5 ± 19.9) ≫ dendocarbin A (no activity). To determine putative structural features underlying the differences in inhibitory potency at hα4β2 AChRs, additional structure-activity relationship and molecular docking experiments were performed. The Ca2+ influx and structural results supported a noncompetitive mechanism of inhibition, where drimenin interacted with luminal and nonluminal (TMD-β2 intrasubunit) sites. The structure-activity relationship results, i.e., the lower the ligand polarity, the higher the inhibitory potency, supported the nonluminal interaction. Ligand binding to both sites might inhibit the hα4β2 AChR by a cooperative mechanism, as shown experimentally (nH > 1). Drimenin could be used as a molecular scaffold for the development of more potent inhibitors with higher selectivity for the hα4β2 AChR.}, language = {en} } @article{HeydenreichKochKleinpeteretal.1997, author = {Heydenreich, Matthias and Koch, Andreas and Kleinpeter, Erich and Zimmermann, Thomas}, title = {Dynamic NMR study of the flexibility of 2-amino-3-aroyl-4,6-diaryl-pyrylium salts}, issn = {0937-0633}, doi = {10.1007/s002160050205}, year = {1997}, language = {en} } @article{HeydenreichKochKovacsetal.2004, author = {Heydenreich, Matthias and Koch, Andreas and Kovacs, J. and Toth, G. and Kleinpeter, Erich}, title = {Electronic influences on (3)J(C,H) coupling constants via -S-, -S(O)- and -SO2--: their determination, calculation and comparison of detection methods}, issn = {0749-1581}, year = {2004}, abstract = {(3)J(C,H) coupling constants via a sulfur atom in two series of compounds, both including a sulfide, a sulfoxide and a sulfone, were detected experimentally and calculated by quantum mechanical methods. In the first series (1-3) the coupling between a hydrogen, bonded to an Sp(3) carbon, and an Sp(2) carbon is treated; the second series (4- 6) deals with the coupling between a hydrogen, bonded to an Sp3 carbon, and an Sp3 carbon. Different pulse sequences (broadband HMBC, SelJres, 1D HSQMBC, J-HMBC-2, selective J-resolved long-range experiment and IMPEACH-MBC) proved to be useful in determining the long-range (3)J(C,H) coupling constants. However, the dynamic behaviour of two of the compounds (4 and 6) led to weighted averages of the two coupling constants expected (concerning equatorial and axial positions of the corresponding hydrogens). DFT calculations proved to be useful to calculate not only the (3)J(C,H) coupling constants but also the different contributions of FC, PSO, DSO and SD terms; the calculation of the Fermi contact term (FC) was found to be sufficient for the correct estimation of (3)J(C,H) coupling constants. Copyright (C) 2004 John Wiley Sons, Ltd}, language = {en} } @article{HeydenreichPoleschnerSchilde1996, author = {Heydenreich, Matthias and Poleschner, Helmut and Schilde, Uwe}, title = {Fluoroselenenylation of Acetylenes with Xenon Difluoride-Diorganyl Diselenides : synthesis and structure elucidation of functionalized Vicinal (E)-Fluoro(organylseleno)olefins}, year = {1996}, language = {en} } @article{PoleschnerHeydenreichSpindleretal.1994, author = {Poleschner, Helmut and Heydenreich, Matthias and Spindler, Karla and Haufe, G.}, title = {Fluoroselenenylation of acetylenes with xenon difluoride/diorganyl diselenides and xenon difluoride/ phenylseleno trialkylsilanes}, year = {1994}, language = {en} } @article{YenesewMidiwoHeydenreichetal.1998, author = {Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Peter, Martin G.}, title = {Four isoflavanones from stem bark of erythrina sacleuxii}, year = {1998}, language = {en} }