TY  - JOUR
A1  - Muiva-Mutisya, Lois
A1  - Macharia, Bernard
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Akala, Hoseah M.
A1  - Derese, Solomon
A1  - Omosa, Leonidah K.
A1  - Yusuf, Amir O.
A1  - Kamau, Edwin
A1  - Yenesew, Abiy
T1  - 6 alpha-Hydroxy-alpha-toxicarol and (+)-tephrodin with antiplasmodial activities from Tephrosia species
JF  - Phytochemistry letters
N2  - 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.
KW  - Tephrosia villosa
KW  - Tephrosia purpurea
KW  - 6 alpha-Hydroxy-alpha-toxicarol
KW  - (+)-Tephrodin
KW  - Plasmodium falciparum
Y1  - 2014
U6  - https://doi.org/10.1016/j.phytol.2014.09.002
SN  - 1874-3900
SN  - 1876-7486
VL  - 10
SP  - 179
EP  - 183
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
A1  - Schulz, Stefanie
A1  - Wacker, Philipp
T1  - Interplay of para- and diatropic ring currents [(anti)aromaticity] of macrocyclic rings subject to conformational influences, further annelation and hydrogenation of aromatic ring moieties
JF  - Tetrahedron
N2  - The spatial magnetic properties (Through Space NMR Shieldings-TSNMRS) of a variety of porphyrins, hemiporphyrazines and tetraoxo[8]circulenes have been computed, visualized as Iso-chemical Shielding Surfaces (ICSS) of various size and direction, and were examined subject to the interplay of present (para)-diatropic ring currents [(anti)aromaticity] and influences on the latter property originating from the macrocyclic ring conformation, further annelation and partial to complete hydrogenation of aromatic ring moieties. Caution seems to be indicated when concluding from a single NICS parameter to present (para)diatropic ring currents [(anti)aromaticity]. (C) 2014 Elsevier Ltd. All rights reserved.
KW  - Porphyrins
KW  - Hemiporphyrazines
KW  - Tetraoxo[8]circulenes
KW  - (Anti)aromaticity
KW  - Anisotropy effect
KW  - Theoretical calculations
Y1  - 2014
U6  - https://doi.org/10.1016/j.tet.2014.10.018
SN  - 0040-4020
VL  - 70
IS  - 48
SP  - 9230
EP  - 9239
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Zborowski, Krzysztof Kazimierz
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
A1  - Proniewicz, Leonard Marian
T1  - Searching for aromatic celate rings. Oxygen versus Thio and Seleno Ligands
JF  - Zeitschrift für physikalische Chemie : international journal of research in physical chemistry and chemical physics
N2  - As a part of searching for fully aromatic chelate compounds, copper complexes of malondialdehyde as well as its sulfur and selenium derivatives were investigated using the DFT quantum chemical methods. Chelate complexes of both Cu(I) and Cu(II) ions wereconsidered. Aromaticity of the metal complexes studied were analyzed using NICS(0), NICS(1), PDI, I-ring, MCI, ICMCI and I-B aromaticity indices, and by TSNMRS visualizations of the spatial magnetic properties. It seems that partial aromaticityof studied chelates increases when oxygen atoms in malondialdehyde are replaced by sulfur and selenium.
KW  - Aromaticity
KW  - Chelatoaromaticity
KW  - Copper Metal Complexes
KW  - Quantum Chemical Calculations
Y1  - 2014
U6  - https://doi.org/10.1515/zpch-2014-0528
SN  - 0942-9352
VL  - 228
IS  - 8
SP  - 869
EP  - 878
PB  - De Gruyter
CY  - Berlin
ER  -