TY  - JOUR
A1  - Zala, Eva
A1  - Struszczyk, Marcin Henryk
A1  - Peter, Martin G.
T1  - Effects of preparation methods for chitosan films on their properties
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Yenesew, Abiy
A1  - Twinomuhwezi, Hannington
A1  - Kiremire, Bernard T.
A1  - Mbugua, Martin N.
A1  - Gitu, Peter M.
A1  - Heydenreich, Matthias
A1  - Peter, Martin G.
T1  - 8-Methoxyneorautenol and radical scavenging flavonoids from Erythrina abyssinica
N2  - 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)]
Y1  - 2009
UR  - http://www.ajol.info/journal_index.php?jid=120&ab=bcse
SN  - 1011-3924
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  - 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  - 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  - 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  - 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  - 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  - 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  - 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  - 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  - Vijayakrishnan, Balakumar
A1  - Issaree, Arisara
A1  - Corilo, Yuri E.
A1  - Ferreira, Christina Ramires
A1  - Eberlin, Marcos N.
A1  - Peter, Martin G.
T1  - MSn of the six isomers of (GlcN)(2)(GlcNAc)(2) aminoglucan tetrasaccharides (diacetylchitotetraoses) rules of fragmentation for the sodiated molecules and application to sequence analysis of hetero-chitooligosaccharides
JF  - Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides
N2  - The six possible isomers of di-N-acetylchitotetraoses [AADD, ADDA, ADAD, DADA, DAAD, and DDAA, where D stands for 2-amino-2-deoxy-3-D-glucose (GlcN) and A for 2-acetamido-2-deoxy-beta-D-glucose (GlcNAc)] were analyzed by ESI(+)-MSn. Collision induced dissociation via MSn experiments were performed for the sodiated molecules of m/z 769 [M+Na](+) for each isomer, and fragments were generated mainly by glycosidic bond and cross-ring cleavages. Rules of fragmentation were then established. A reducing end D residue yields the (O.2)A(4) cross-ring [M-59+Na](+) fragment of m/z 710 as the most abundant, whereas isomers containing a reducing end A prefer to lose water to form the [M-18+Na](+) ion of m/z 751, as well as abundant (O.2)A(4) cross-ring [M-101+Na](+) fragments of m/z 668 and B-3 [M-221+Na](+) ions of m/z 548. MS3 of C- and Y-type ions shows analogous fragmentation behaviour that allows identification of the reducing end next-neighbour residue. Due to gas-phase anchimeric assistance, B-type cleavage between the glycosidic oxygen and the anomeric carbon atom is favoured when the glycon is an A residue. Relative ion abundances are generally in the order B >> C > Y, but may vary depending on the next neighbour towards the non-reducing end. These fragmentation rules were used for partial sequence analysis of hetero-chitooligosaccharides of the composition D(2)A(3), D(3)A(3), D(2)A(4), D(4)A(3), and D(3)A(4).
KW  - Chitosan
KW  - Fragmentation
KW  - Oligosaccharides
KW  - Sequence analysis
KW  - Tandem mass spectrometry
Y1  - 2011
U6  - https://doi.org/10.1016/j.carbpol.2010.04.041
SN  - 0144-8617
VL  - 84
IS  - 2
SP  - 713
EP  - 726
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - van Aalten, Daan M. F.
A1  - Komander, David
A1  - Synstad, Bjoenar
A1  - Gaseidnes, Sigrid
A1  - Peter, Martin G.
A1  - Eijsink, Vincent G. H.
T1  - Structural Insights into the catalytic mechanism of a family 18 exochitinase
N2  - Chitinase B (ChiB) from Serratia marcescens is a family 18 exochitinase whose catalytic domain has a TIM-barrel fold with a tunnel-shaped active site. We have solved structures of three ChiB complexes that reveal details of substrate binding, substrateassisted catalysis, and product displacement. The structure of an inactive ChiB mutant (E144Q) complexed with a pentameric substrate (binding in subsites 22 to 13) shows closure of the ''roof'' of the active site tunnel. It also shows that the sugar in the 21 position is distorted to a boat conformation, thus providing structural evidence in support of a previously proposed catalytic mechanism. The structures of the active enzyme complexed to Allosamidin (an analogue of a proposed reaction intermediate) and of the active enzyme soaked with pentameric substrate show events after cleavage of the glycosidic bond. The latter structure shows reopening of the roof of the active site tunnel and enzyme-assisted product displacement in the 11 and 12 sites, allowing a water molecule to approach the reaction center. Catalysis is accompanied by correlated structural changes in the core of the TIM barrel that involve conserved polar residues whose functions were hitherto unknown. These changes simultaneously contribute to stabilization of the reaction intermediate and alternation of the pKa of the catalytic acid during the catalytic cycle.
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Vaaje-Kolstad, G.
A1  - Vasella, A.
A1  - Peter, Martin G.
A1  - Netter, C.
A1  - Houston, Douglas R.
A1  - Westereng, B.
A1  - Synstad, Bjoenar
A1  - Eijsink, Vincent G. H.
A1  - van Aalten, Daan M. F.
T1  - Interactions of a family 18 chitinase with the designed inhibitor HM508 and its degradation product, chitobiono- delta-lactone
N2  - We describe enzymological and structural analyses of the interaction between the family 18 chitinase ChiB from Serratia marcescens and the designed inhibitor N,N'-diacetylchitobionoxime-N-phenylcarbamate (HM508). HM508 acts as a competitive inhibitor of this enzyme with a K-i in the 50 muM range. Active site mutants of ChiB show K-i values ranging from 1 to 200 muM, providing insight into some of the interactions that determine inhibitor affinity. Interestingly, the wild type enzyme slowly degrades HM508, but the inhibitor is essentially stable in the presence of the moderately active D142N mutant of ChiB. The crystal structure of the D142N-HM508 complex revealed that the two sugar moieties bind to the -2 and -1 subsites, whereas the phenyl group interacts with aromatic side chains that line the +1 and +2 subsites. Enzymatic degradation of HM508, as well as a Trp-->Ala mutation in the +2 subsite of ChiB, led to reduced affinity for the inhibitor, showing that interactions between the phenyl group and the enzyme contribute to binding. Interestingly, a complex of enzymatically degraded HM508 with the wild type enzyme showed a chitobiono-delta- lactone bound in the -2 and -1 subsites, despite the fact that the equilibrium between the lactone and the hydroxy acid forms in solution lies far toward the latter. This shows that the active site preferentially binds the E-4 conformation of the -1 sugar, which resembles the proposed transition state of the reaction
Y1  - 2004
SN  - 0021-9258
ER  - 
TY  - JOUR
A1  - Tsukamoto, Junko
A1  - Haebel, Sophie
A1  - Valenca, Gustavo P.
A1  - Peter, Martin G.
A1  - FRanco, Telma T.
T1  - Enzymatic direct synthesis of acrylic acid esters of mono- and disaccharides
N2  - Background: There is an increased need to replace materials derived from fossil sources by renewables. Sugar- cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the prepn. of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous prepn. of protected sugar derivs., such as glycosides, or activated acrylates, such as vinyl acrylate. Results: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of mol. sieves was investigated. The reactions were monitored by high-performance liq. chromatog. (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was obsd. for the D-glucose and D- fructose, followed by D-xylose and D-maltose. Mol. sieves had no pronounced effect on the conversion. Conclusions: A feasible method is described to produce and to characterize sugar acrylates, including those contg. more than two acrylate groups. The process for prodn. of these higher esters could potentially be optimized further to produce mols. for crosslinking in acrylate polymn. and other applications. The direct enzymic esterification of free carbohydrates with acrylic acid is unprecedented. [on SciFinder (R)].
Y1  - 2008
UR  - http://www3.interscience.wiley.com/journal/117946200/grouphome/home.html
SN  - 0268-2575
ER  - 
TY  - JOUR
A1  - Thiele, Gabriela
A1  - Rottmann, Antje
A1  - Germer, Antje
A1  - Kleinpeter, Erich
A1  - Spindler, Klaus-Dieter
A1  - Synstad, Bjoenar
A1  - Eijsink, Vincent G. H.
A1  - Peter, Martin G.
T1  - Synthesis and conformational analysis of pseudosugar analogues of chitotriose
N2  - In this article, the synthesis of analogs of N,N',N''-triacetylchitotriose in which the central sugar residue was replaced by a succinic acid is presented. Mol. modeling calcns. revealed that the pseudotrisaccharides exist in low energy extended conformations which show similar space filling as N,N',N''-triacetylchitotriose. Of the N,N',N''-triacetylchitotriose pseudosugar analogs tested as chitinase inhibitors, none showed any appreciable competition (numerical data not presented). The conformational anal. along with further synthetic efforts will hopefully lead to more efficient pseudosaccharides as chitinase inhibitors.
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Ratajska, M.
A1  - Boryniec, Stefan
A1  - Peter, Martin G.
A1  - Loth, Fritz
T1  - The determination of the degree of N-acetylation of chitosan
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Pospieszny, Henryk
A1  - Schanzenbach, Dirk
A1  - Peter, Martin G.
T1  - Biodegradation of various chitosans using Aspergillus fumigatus
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Pospieszny, Henryk
A1  - Peter, Martin G.
T1  - Biodegradation of films and paper sheets containing chitosan
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Peter, Martin G.
T1  - Analysis of deacetylation deree in chitosans from various sources
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Peter, Martin G.
T1  - Calibration of methods for the determination of the degree of decatetylation of chitosan
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Peter, Martin G.
T1  - Properties of microcrystalline chitosan gel-like dispersion and formed films
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Peter, Martin G.
T1  - Preparation of paper sheets containing microcrystalline chitosan
Y1  - 1999
SN  - 3-9806494-5-8
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Peter, Martin G.
T1  - Method of microcrystalline chitosan-protein films preparation
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Loth, Fritz
A1  - Köhler, L. A.
A1  - Peter, Martin G.
T1  - Characterization of chitosan
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Struszczyk, Marcin Henryk
A1  - Halweg, R.
A1  - Peter, Martin G.
T1  - Comparative analysis of chitosans from insects and crustacea
Y1  - 1999
SN  - 3-9806494-5-8
ER  - 
TY  - JOUR
A1  - Streffer, Katrin
A1  - Kaatz, Helvi
A1  - Bauer, Christian G.
A1  - Makower, Alexander
A1  - Schulmeister, Thomas
A1  - Scheller, Frieder W.
A1  - Peter, Martin G.
A1  - Wollenberger, Ursula
T1  - Application of a sensitive catechol detector for determination of tyrosinase inhibitors
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Schumacher-Wandersleb, Michael H. M. G.
A1  - Petersen, Stefan
A1  - Peter, Martin G.
T1  - Preparation of the N-Acetylglucosaminidase inhibitor 1-Acetamido-1,2,5-tride oxy-2,5-imino-D-glucitol from methyl a-D-Mannopyranoside
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Schumacher-Wandersleb, Michael H. M. G.
A1  - Peter, Martin G.
T1  - Synthesis of chitobiosyl pyrrolidines
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Schanzenbach, Dirk
A1  - Peter, Martin G.
T1  - NMR spectroscopy of chito-oligosaccharides
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Schanzenbach, Dirk
A1  - Peter, Martin G.
T1  - Chromatography of chito-oligosaccarides
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Schanzenbach, Dirk
A1  - Matern, Christa-Maria
A1  - Peter, Martin G.
T1  - Cleavage of chitin by means of sulfurice acid/acetc anhydride and isolation of peracetylated chito- oligosaccharides
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Schanzenbach, Dirk
A1  - Matern, Christa-Maria
A1  - Peter, Martin G.
T1  - Synthesis of glycosylamines and glycopeptides
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Rusu, Viorel Marin
A1  - Ng, C. H.
A1  - Wilke, Max
A1  - Tiersch, Brigitte
A1  - Fratzl, Peter
A1  - Peter, Martin G.
T1  - Size-controlled hydroxyapatite nanoparticles as self-organized organic-in organic composite materials
N2  - This paper presents some results concerning the size-controlled hydroxyapatite nanoparticles obtained in aqueous media in a biopolymer matrix from soluble precursors salts. Taking the inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite was investigated. A stepwise co-precipitation approach was used to obtain different types of composites by means of different ratio between components. The synthesis of hydroxyapatite was carried out in the chitosan matrix from calcium chloride and sodium dihydrogenphosphate in alkaline solutions at moderate pH of 10-11 for 24 h. Our research is focused on studying and understanding the structure of this class of composites, aiming at the development of novel materials, controlled at the nanolevel scale. The X-ray diffraction technique was employed in order to study the kinetic of hydroxyapatite formation in the chitosan matrix as well as to determine the HAp crystallite sizes in the composite samples. The hydroxyapatite synthesized using this route was found to be nano-sized (15-50nm). Moreover, applying an original approach to analyze the (002) XRD diffraction peak profile of hydroxyapatite by using a sum of two Gauss functions, the bimodal distribution of nanosized hydroxyapatite within the chitosan matrix was revealed. Two types of size distribution domains such as cluster-like (between 200 and 400 nm), which are the habitat of "small" hydroxyapatite nanocrystallites and scattered-like, which are the habitat of "large" hydroxyapatite nanocrystallites was probed by TEM and CSLM. The structural features of composites suggest that self-assembly processes might be involved. The composites contain nanosized hydroxyapatite with structural features close to those of biological apatites that make them attractive for bone tissue engineering applications. (c) 2005 Elsevier Ltd. All rights reserved
Y1  - 2005
SN  - 0142-9612
ER  - 
TY  - JOUR
A1  - Rukunga, G. M.
A1  - Muregi, F. W.
A1  - Omar, S. A.
A1  - Gathirwa, J. W.
A1  - Muthaura, C. N.
A1  - Peter, Martin G.
T1  - Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus
N2  - Two sesquiterpenes, corymbolone and mustakone, isolated from the chloroform extract of the rhizomes of Cyperus articulatus, exhibited significant anti-plasmodial properties. Mustakone was approximately ten times more active than corymbolone against the sensitive strains of the Plasmodium falciparum.
Y1  - 2008
SN  - 0367-326X
ER  - 
TY  - JOUR
A1  - Rottmann, Antje
A1  - Synstad, Bjoenar
A1  - Thiele, G.
A1  - Schanzenbach, Dirk
A1  - Eijsink, Vincent G. H.
A1  - Peter, Martin G.
T1  - Approaches towards the design of new chitinase inhibitors
Y1  - 1999
SN  - 3-9806494-5-8
ER  - 
TY  - JOUR
A1  - Rottmann, Antje
A1  - Synstad, Bjoenar
A1  - Eijsink, Vincent G. H.
A1  - Peter, Martin G.
T1  - Synthesis of N-acetylglucosaminyl and diacetylchitobiosyl amides of heterocyclic carboxylic acids as potential chitinase inhibitors
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Ratajska, M.
A1  - Struszczyk, Marcin Henryk
A1  - Boryniec, Stefan
A1  - Peter, Martin G.
A1  - Loth, Fritz
T1  - The degree of acetylation of chitosan : optimization of the IR Method
Y1  - 1997
ER  - 
TY  - GEN
A1  - Peter, Martin G.
A1  - Yenesew, Abiy
A1  - Twinomuhwezi, Hannington
A1  - Kabaru, Jacques M.
A1  - Akala, Hoseah M.
A1  - Kiremire, Bernard T.
A1  - Heydenreich, Matthias
A1  - Eyase, Fredrick
A1  - Waters, Norman C.
A1  - Walsh, Douglas S.
T1  - Antiplasmodial and larvicidal flavonoids from Derris trifoliata
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 121 
KW  - Derris trifoliata
KW  - Leguminosae
KW  - Flavanone
KW  - (S)-Lupinifolin 4´-methyl ether
KW  - Lupinifolin
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-44614
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
A1  - Wollenberger, Ursula
T1  - Phenol-oxidizing enzymes : mechanisms and applications
Y1  - 1997
ER  - 
TY  - GEN
A1  - Peter, Martin G.
A1  - Muiva, Lois M.
A1  - Yenesew, Abiy
A1  - Derese, Solomon
A1  - Heydenreich, Matthias
A1  - Akala, Hoseah M.
A1  - Eyase, Fredrick
A1  - Waters, Norman C.
A1  - Mutai, Charles
A1  - Keriko, Joseph M.
A1  - Walsh, Douglas S.
T1  - Antiplasmodial β-hydroxydihydrochalcone from seedpods of Tephrosia elata
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 118 
KW  - Tephrosia elata
KW  - Leguminosae
KW  - Seedpods
KW  - (S)-Elatadihydrochalcone
KW  - β-Hydroxydihydrochalcone
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-44437
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
A1  - Merz, A.
T1  - Stereoselective benzylic deprotonation in the enzymatic rearrangement of N-acetyldopamine derived o-Quinone to the p-Quinone methide
Y1  - 1995
SN  - 0957-4166
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
A1  - Ley, J. P.
A1  - Petersen, Stefan
A1  - Londershausen, M.
A1  - Schumacher-Wandersleb, Michael H. M. G.
A1  - Spindler, Klaus-Dieter
A1  - Spindler-Barth, Margarethe
A1  - Turberg, Andreas
T1  - Synthesis of chitinase inhibitors
Y1  - 1994
ER  - 
TY  - GEN
A1  - Peter, Martin G.
A1  - Förster, Hans
T1  - On the structure of Eumelanins : identification of constitutional patterns by solid-state NMR spectroscopy
N2  - Aus dem Inhalt: Melanins are complex polyphenolic polymers. They are usually formed in nature by enzyme-catalyzed oxidative polymerization of o-diphenols. The deep black eumelanins, derived from Dopa 1 or dopamine 3, are distinguished from the yellow to brown phaeomelanins obtained from Dopa in the presence of cysteine. Characteristic of eumelanins are the indole units, which are formed from catecholamines by intramolecular addition of the amino groups to the oxidatively generated o-quinones. [...]
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 053 
Y1  - 1989
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17027
ER  - 
TY  - GEN
A1  - Peter, Martin G.
A1  - Andersen, Svend Olav
A1  - Hartmann, Rudolf
A1  - Miessner, Merle
A1  - Roepstorff, Peter
T1  - Catecholamine-protein conjugates : isolation of 4-phenylphenoxazin-2-ones from oxidative coupling of N-acetyldopamine with alipathic amino acids
N2  - 4-Phenylphenoxazinones were isolated after biomimetic oxidation, using diphenoloxidases of insect cuticle, mushroom tyrosinase, or after autoxidation of N-acetyldopamine (Image ) in the presence of β-alanine, β-alanine methyl ester or N-acetyl-L-lysine. They are formed presumably by addition of 2-aminoalkyl-5-alkylphenols to the o-quinone of biphenyltetrol which, in turn, arises from oxidative coupling of. The structures of present the first examples for the assembly of reasonably stable intermediates in the rather complex process of chemical modifications of aliphatic amino acid residues by o-quinones.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 062 
Y1  - 1992
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17571
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
A1  - Andersen, S. O.
T1  - The molecular architecture of the insect exoskeleton
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
T1  - Chitin and Chitosan from Animal Sources
N2  - A review on the chem. and biochem. of chitin and the chem. and application of chitosan. The following topics were discussed: structure of chitin and chitosan; occurrence and physiol. functions of chitin; detection of chitin in animals and anal. of chitin and chitosan; biosynthesis and biodegrdn. of chitin in animals; prodn. of chitin and chitosan; properties of chitin and chitosan; and applications of chitin and chitosan.
Y1  - 2002
SN  - 3-527-30227-1
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
T1  - Chitin and Chitosan from Fungi
Y1  - 2002
SN  - 3-527-30227-1
ER  - 
TY  - JOUR
A1  - Peter, Martin G.
T1  - Applications and environmental aspects of chitin and chitosan
Y1  - 1995
SN  - 0022-233X
ER  -