The IPB has once again been recognized for its exemplary actions in terms of equal opportunity-oriented personnel and organizational policies and has received the TOTAL E-QUALITY certification for the…
The Plant Science Student Conference (PSSC) has been organised by students from the two Leibniz institutes, IPK and IPB, every year for the last 20 years. In this interview, Christina Wäsch (IPK) and…
Hoffmann, A.; Nong, J. P.; Porzel, A.; Bremer, M.; Fischer, S.;Modification of Lignoboost Kraft Lignin from softwoods with dihydroxybenzenesReact. Funct. Polym.142112-118(2019)DOI: 10.1016/j.reactfunctpolym.2019.06.011
Lignin, a component of the cell walls of plants and the second most abundant biopolymer has long been regarded as disturbing substance in pulp production by paper industry. This view has changed in recent decades. Thus, lignin is increasingly regarded as an alternative to crude oil. Tuned and modified lignins have suitable properties to use them as building blocks for various applications as well as for the production of basic chemicals. By modifying lignin, its reactivity and uniformity can be increased. In addition, properties of the lignin can be changed and influenced by selective modification. By a solvent-free modification with dihydroxybenzene, aliphatic OH groups of the lignin side chain can be removed and covalent CC bonds to the aromatics can be formed. At the same time, aryl-alkyl ether cleavage occurs, which reduces the molecular weight of lignin by about one third. In addition, ongoing reactions result in the reduction in the molecular weight distribution. All this leads to a more uniform and reactive lignin which is interesting as a precursor for various applications. This work provides a deeper understanding of ongoing reactions with dihydroxybenzenes and the structure of modified lignins.
Publications
Greff, A.; Porzel, A.; Schmidt, J.; Palfner, G.; Arnold, N.;Pigment pattern of the Chilean mushroom Dermocybe nahuelbutensis Garrido & E. HorakRec. Nat. Prod.11547-551(2017)DOI: 10.25135/rnp.69.17.01.027
Fruiting bodies of the Chilean mushroom Dermocybe nahuelbutenis Garrido & E. Horak (syn.: Cortinariusnahuelbutensis (Garrido & E. Horak) E. Valenz. & G. Moreno) were chemically investigated for the first time andafforded the new dimeric anthraqinone 7,7'-emodinphyscion (1) beside the know anthraquinones dermolutein (2),endocrocin (3), skyrin (4) and the dimeric pre-anthraquinone derivative flavomannin C (5). The chemotaxonomicsignificance of the pigments is discussed.
Publications
Alresly, Z.; Lindequist, U.; Lalk, M.; Porzel, A.; Arnold, N.; Wessjohann, L. A.;Bioactive Triterpenes from the Fungus Piptoporus betulinusRec. Nat. Prod.10103-108(2016)
Phytochemical investigation of the ethyl acetate extract of the fruiting bodies from the basidiomycete Piptoporus betulinus led to the isolation of a new bioactive lanostane triterpene identified as 3 b -acetoxy-16-hydroxy-24-oxo-5α-lanosta-8- ene-21-oic acid (1). In addition, ten known triterpenes, polyporenic acid A (5), polyporenic acid C (4), three derivatives of polyporenic acid A (8, 10, 11), betulinic acid (3), betulin (2), ergosterol peroxide (6), 9,11-dehydroergosterol peroxide (7), and fomefficinic acid (9), were also isolated from the fungus. All isolated compounds were tested for antimicrobial activity against some Gram-positive and Gram-negative bacteria as well as against a fungal strain. The new triterpene and some of the other compounds showed antimicrobial activity against Gram-positive bacteria.
Publications
Ali, N. A. A.; Wurster, M.; Arnold, N.; Lindequist, U.; Wessjohann, L.;Essential Oil Composition from Oleogum Resin of Soqotraen Commiphora kuaRec. Nat. Prod.270-75(2008)
The major constituents of the essential oil obtained by hydrodistillation from the oleogum resin of Commiphora kua Vollesen were identified by GC-MS. Sixteen constituents were detected from the essential oil, which constituted about (90.5%) of the total amount. Major constituents of the oil were α- cadinol (33.0%), g -cadinene (22.5%), d -cadinene (17.0%), isocaryophyllene (3.7%), allo-aromadendrene (2.8%), α-muurolene (2.7%), and α-humulene (2.4%). The Oil of Commiphora kua showed moderate antifungal activity against Cladosporium cucumerinum.