Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Is Low-field NMR a Complementary Tool to GC-MS in Quality Control of Essential Oils? A Case Study : Patchouli Essential Oil *
    Krause, Andre ; Wu, Yu ; Tian, Runtao ; Beek, Teris A. van - \ 2018
    Planta Medica 84 (2018)12/13. - ISSN 0032-0943 - p. 953 - 963.
    60 MHz H-NMR - adulteration - chemometrics - essential oil - fingerprinting - patchouli - quality control
    High-field NMR is an expensive and important quality control technique. In recent years, cheaper and simpler low-field NMR has become available as a new quality control technique. In this study, 60 MHz 1 H-NMR was compared with GC-MS and refractometry for the detection of adulteration of essential oils, taking patchouli essential oil as a test case. Patchouli essential oil is frequently adulterated, even today. In total, 75 genuine patchouli essential oils, 10 commercial patchouli essential oils, 10 other essential oils, 17 adulterants, and 1 patchouli essential oil, spiked at 20% with those adulterants, were measured. Visual inspection of the NMR spectra allowed for easy detection of 14 adulterants, while gurjun and copaiba balsams proved difficult and one adulterant could not be detected. NMR spectra of 10 random essential oils differed not only strongly from patchouli essential oil but also from one another, suggesting that fingerprinting by low-field NMR is not limited to patchouli essential oil. Automated chemometric evaluation of NMR spectra was possible by similarity analysis (Mahalanobis distance) based on the integration from 0.1 – 8.1 ppm in 0.01 ppm increments. Good quality patchouli essential oils were recognised as well as 15 of 17 deliberate adulterations. Visual qualitative inspection by GC-MS allowed for the detection of all volatile adulterants. Nonvolatile adulterants, and all but one volatile adulterant, could be detected by semiquantitation. Different chemometric approaches showed satisfactory results. Similarity analyses were difficult with nonvolatile adulterants. Refractive index measurements could detect only 8 of 17 adulterants. Due to advantages such as simplicity, rapidity, reproducibility, and ability to detect nonvolatile adulterants, 60 MHz 1 H-NMR is complimentary to GC-MS for quality control of essential oils.
    Valencene oxidase CYP706M1 from Alaska cedar (Callitropsis nootkatensis)
    Cankar, K. ; Houwelingen, A.M.M.L. van; Goedbloed, M.A. ; Renirie, R. ; Jong, R.M. de; Bouwmeester, H.J. ; Bosch, H.J. ; Sonke, Th. ; Beekwilder, M.J. - \ 2014
    FEBS Letters 588 (2014)6. - ISSN 0014-5793 - p. 1001 - 1007.
    essential oil - functional-characterization - ixodes-scapularis - cytochrome-p450 monooxygenase - amblyomma-americanum - yeast expression - acari ixodidae - yellow-cedar - mint mentha - nootkatone
    (+)-Nootkatone is a natural sesquiterpene ketone used in grapefruit and citrus flavour compositions. It occurs in small amounts in grapefruit and is a major component of Alaska cedar (Callitropsis nootkatensis) heartwood essential oil. Upon co-expression of candidate cytochrome P450 enzymes from Alaska cedar in yeast with a valencene synthase, a C. nootkatensis valencene oxidase (CnVO) was identified to produce trans-nootkatol and (+)-nootkatone. Formation of (+)-nootkatone was detected at 144 ± 10 lg/L yeast culture. CnVO belongs to a new subfamily of the CYP706 family of cytochrome P450 oxidases.
    Valencene synthase from the heartwood of Nootka cypress (Callitropsis nootkatensis) for biotechnological production of valencene
    Beekwilder, M.J. ; Houwelingen, A.M.M.L. van; Cankar, K. ; Dijk, A.D.J. van; Jong, R. de; Stoopen, G.M. ; Bouwmeester, H.J. ; Achkar, J. ; Sonke, Th. ; Bosch, H.J. - \ 2014
    Plant Biotechnology Journal 12 (2014)2. - ISSN 1467-7644 - p. 174 - 182.
    antimalarial agent artemisinin - functional-characterization - phytophthora-ramorum - ixodes-scapularis - terpene synthases - essential oil - biosynthesis - yeast - metabolism - expression
    Nootkatone is one of the major terpenes in the heartwood of the Nootka cypress Callitropsis nootkatensis. It is an oxidized sesquiterpene, which has been postulated to be derived from valencene. Both valencene and nootkatone are used for flavouring citrus beverages and are considered among the most valuable terpenes used at commercial scale. Functional evaluation of putative terpene synthase genes sourced by large-scale EST sequencing from Nootka cypress wood revealed a valencene synthase gene (CnVS). CnVS expression in different tissues from the tree correlates well with nootkatone content, suggesting that CnVS represents the first dedicated gene in the nootkatone biosynthetic pathway in C. nootkatensis The gene belongs to the gymnosperm-specific TPS-d subfamily of terpenes synthases and its protein sequence has low similarity to known citrus valencene synthases. In vitro, CnVS displays high robustness under different pH and temperature regimes, potentially beneficial properties for application in different host and physiological conditions. Biotechnological production of sesquiterpenes has been shown to be feasible, but productivity of microbial strains expressing valencene synthase from Citrus is low, indicating that optimization of valencene synthase activity is needed. Indeed, expression of CnVS in Saccharomyces cerevisiae indicated potential for higher yields. In an optimized Rhodobacter sphaeroides strain, expression of CnVS increased valencene yields 14-fold to 352 mg/L, bringing production to levels with industrial potential
    Gene Coexpression Analysis Reveals Complex Metabolism of the Monoterpene Alcohol Linalool in Arabidopsis FlowersW
    Ginglinger, J.F. ; Boachon, B. ; Hofer, R. ; Paetz, C. ; Kollner, T.G. ; Miesch, L. ; Lugan, R. ; Baltenweck, R. ; Mutterer, J. ; Ullman, P. ; Verstappen, F.W.A. ; Bouwmeester, H.J. - \ 2013
    The Plant Cell 25 (2013)11. - ISSN 1040-4651 - p. 4640 - 4657.
    cytochrome-p450 limonene hydroxylases - avocado persea-americana - functional expression - endoplasmic-reticulum - terpene synthases - mint mentha - saccharomyces-cerevisiae - beta-glucuronidase - essential oil - floral scent
    The cytochrome P450 family encompasses the largest family of enzymes in plant metabolism, and the functions of many of its members in Arabidopsis thaliana are still unknown. Gene coexpression analysis pointed to two P450s that were coexpressed with two monoterpene synthases in flowers and were thus predicted to be involved in monoterpenoid metabolism. We show that all four selected genes, the two terpene synthases (TPS10 and TPS14) and the two cytochrome P450s (CYP71B31 and CYP76C3), are simultaneously expressed at anthesis, mainly in upper anther filaments and in petals. Upon transient expression in Nicotiana benthamiana, the TPS enzymes colocalize in vesicular structures associated with the plastid surface, whereas the P450 proteins were detected in the endoplasmic reticulum. Whether they were expressed in Saccharomyces cerevisiae or in N. benthamiana, the TPS enzymes formed two different enantiomers of linalool: (-)-(R)-linalool for TPS10 and (+)-(S)-linalool for TPS14. Both P450 enzymes metabolize the two linalool enantiomers to form different but overlapping sets of hydroxylated or epoxidized products. These oxygenated products are not emitted into the floral headspace, but accumulate in floral tissues as further converted or conjugated metabolites. This work reveals complex linalool metabolism in Arabidopsis flowers, the ecological role of which remains to be determined.
    Ethnoknowledge of Bukusu community on livestock tick prevention and control in Bungoma district, western Kenya
    Wanzala, W.W. ; Takken, W. ; Mukabana, W.R. ; Pala, A.O. ; Hassanali, A. - \ 2012
    Journal of Ethnopharmacology 140 (2012)2. - ISSN 0378-8741 - p. 298 - 324.
    medicinal-plants - melia-azedarach - traditional medicine - physalis-peruviana - rhipicephalus-appendiculatus - stereospermum-kunthianum - agave-sisalana - essential oil - antiplasmodial activity - antimicrobial activity
    ETHNOPHARMACOLOGICAL RELEVANCE: To date, nomadic communities in Africa have been the primary focus of ethnoveterinary research. The Bukusu of western Kenya have an interesting history, with nomadic lifestyle in the past before settling down to either arable or mixed arable/pastoral farming systems. Their collective and accumulative ethnoveterinary knowledge is likely to be just as rich and worth documenting. AIM OF THE STUDY: The aim of the present study was to document indigenous knowledge of the Bukusu on the effect of livestock ticks and ethnopractices associated with their management. It was envisaged that this would provide a basis for further research on the efficacy of these practices that could also lead to the discovery of useful tick-control agents. MATERIALS AND METHODS: Non-alienating, dialogic, participatory action research (PAR) and participatory rural appraisal (PRA) approaches involving 272 women and men aged between 18 and 118 years from the Bukusu community were used. RESULTS: Ticks are traditionally classified and identified by colour, size, host range, on-host feeding sites, and habitat preference. Tick-associated problems recognised include kamabumba (local reference to East Coast fever, Anaplasmosis or Heartwater diseases transmitted by different species of livestock ticks) and general poor performance of livestock. Traditional methods of controlling ticks include handpicking, on-host use of ethnobotanical suspensions (prepared from one or more of over 150 documented plants) to kill the ticks and prevent re-infestation, fumigation of infested cattle with smoke derived from burning ethnobotanical products, burning pastures, rotational grazing ethnopractices, and livestock quarantine. CONCLUSIONS: The study confirms that the Bukusu have preserved rich ethnoveterinary knowledge and practices. It provides some groundwork for elucidating the efficacy of some of these ethnopractices in protecting livestock from tick disease vectors, particularly those involving the use of ethnobotanicals, which may lead to the discovery of useful ant-tick agents.
    Molecular cloning and characterization of a broad substrate terpenoid oxidoreductase from Artemisia annua.
    Ryden, A.M. ; Ruyter-Spira, C.P. ; Litjens, R. ; Takahashi, S. ; Quax, W.J. ; Osada, H. ; Bouwmeester, H.J. ; Kayser, O. - \ 2010
    Plant and Cell Physiology 51 (2010)7. - ISSN 0032-0781 - p. 1219 - 1228.
    chain dehydrogenases/reductases sdrs - amorpha-4,11-diene synthase - functional assignments - biosynthetic-pathway - essential oil - key enzyme - expression - reductase - peppermint - acid
    From Artemisia annua L., a new oxidoreductase (Red 1) was cloned, sequenced and functionally characterized. Through bioinformatics, heterologous protein expression, and enzyme substrate conversion assays, the elucidation of the enzymatic capacities of Red1 was achieved. Red1 acts on monoterpenoids, and in particular functions as a menthone:neomenthol oxidoreductase. The kinetic parameter kcat/Km was determined to be 939 fold more efficient for the reduction of (-)-menthone to (+)-neomenthol, than results previously reported for the menthone:neomenthol reductase from Mentha x piperita. Based on its kinetic properties, the possible use of Red1 in biological crop protection is discussed.
    Trichome dynamics and artemisinin accumulation during development and senescence of Artemisia annua leaves
    Lommen, W.J.M. ; Schenk, E. ; Bouwmeester, H.J. ; Verstappen, F.W.A. - \ 2006
    Planta Medica 72 (2006)4. - ISSN 0032-0943 - p. 336 - 345.
    dihydroartemisinic acid - biosynthetic precursors - glandular trichomes - antimalarial-drugs - essential oil - identification - plants - ontogeny
    Artemisinin is a sesquiterpene lactone endoperoxide and an important antimalarial drug produced in Artemisia annua. To unravel the diverse processes determining artemisinin yield in A. annua crops, artemisinin accumulation during the development of individual leaves was studied in two field experiments. During the life cycle of a leaf, artemisinin was always present. Quantities were low at leaf appearance and increased steadily. In leaves studied until after senescence, maximum quantities and concentrations were achieved after the leaf had turned brown. The total quantity of possible artemisinin precursors per leaf (dihydroartemisinic acid and other upstream precursors) was highest early in the leaf cycle when the leaf was still expanding. Dihydroartemisinic acid was more abundant than the other compounds and its quantity declined during leaf development whereas that of artemisinin increased. Dihydroartemisinic acid was not converted directly into artemisinin, because on a per leaf basis the decline in molar quantity of precursors in the earliest formed leaves was not compensated for by a simultaneous increase in artemisinin. Our results suggest that a (putative) intermediate such as dihydroartemisinic acid hydroperoxide temporarily may have accumulated in considerable quantities. The number of mature, capitate trichomes on the adaxial leaf side increased after leaf appearance until the end of leaf expansion, and then decreased, probably due to collapse of trichomes. Artemisinin production thus (also) occurred when trichomes were collapsing. Later formed leaves achieved higher concentrations of artemisinin than earlier formed leaves, because of a higher trichome density and a higher capacity per trichome.
    Volatile science? Metabolic engineering of terpenoids in plants
    Aharoni, A. ; Jongsma, M.A. ; Bouwmeester, H.J. - \ 2005
    Trends in Plant Science 10 (2005)12. - ISSN 1360-1385 - p. 594 - 602.
    transgenic arabidopsis plants - linalool synthase gene - isoprenoid biosynthesis - essential oil - monoterpene biosynthesis - diphosphate synthase - s-linalool - functional expression - menthofuran synthase - plastidial pathways
    Terpenoids are important for plant survival and also possess biological properties that are beneficial to humans. Here, we describe the state of the art in terpenoid metabolic engineering, showing that significant progress has been made over the past few years. Subcellular targeting of enzymes has demonstrated that terpenoid precursors in subcellular compartments are not as strictly separated as previously thought and that multistep pathway engineering is feasible, even across cell compartments. These engineered plants show that insect behavior is influenced by terpenoids. In the future, we expect rapid progress in the engineering of terpenoid production in plants. In addition to commercial applications, such transgenic plants should increase our understanding of the biological relevance of these volatile secondary metabolites
    Natural Remedies and Nutraceuticals Used in Ethnoveterinary Practices in Inland Southern Italy
    Pieroni, A. ; Howard, P. ; Volpato, G. ; Santoro, R.F. - \ 2004
    Veterinary Research Communications 28 (2004)1. - ISSN 0165-7380 - p. 55 - 80.
    trinidad-and-tobago - medicinal-plants - antimicrobial activity - veterinary-medicine - northern nigeria - animal diseases - essential oil - phytotherapy - livestock - chimpanzees
    Traditional animal health practices are today only rarely used in Europe, as many natural remedies applied for the treatment of animals have been replaced by modern pharmaceuticals. Modern institutionalized veterinary services tend to cover every aspect of animal health care, and influence most of the veterinary practices carried out by shepherds and farmers. However, in some areas, particularly of the Mediterranean, such traditional practices persist. Few ethnoveterinary studies have been conducted in the Mediterranean. In this survey, we analysed the natural remedies that are still in use or were used until very recently to treat animals in central Lucania (inland southern Italy). Plants constitute the mainstay of the folk-veterinary regimen (about 40 preparations), but there are also a few animal- and mineral-derived preparations. Among them, the veterinary use of Cistus incanus, Colutea arborescens, Daphne laureola, and Erigeron acer is reported for the first time. Moreover, the study identified diverse traditional plant nutraceuticals used to improve animal health, as well as the quality of milk and dairy products. An important potential output of this study may be the development of ecosustainable integrated projects focused on the maintenance of traditional animal breeding and healthcare systems. Pharmacological and toxicological considerations relating to possible applications of the recorded traditional knowledge in modern evidence-based veterinary medicine are also discussed.
    Etnopharmacognostic survey on the natural ingredients used in folk cosmetics, cosmeceuticals and remedies for healing skin deseases in the inland Marches, Central-Eastern Italy
    Pieroni, A. ; Quave, C.L. ; Villanelli, M.L. ; Mangino, P. ; Sabbatini, G. ; Santini, L. ; Boccetti, T. ; Profili, M. ; Ciccioli, T. ; Rampa, L.G. ; Antonini, G. ; Girolamini, C. - \ 2004
    Journal of Ethnopharmacology 91 (2004)2-3. - ISSN 0378-8741 - p. 331 - 344.
    traditional drugs sold - tanacetum-balsamita - ethnopharmacological survey - essential oil - plants - phytotherapy - extracts
    An ethnopharmaceutical Study focused on domestic cosmetics, cosmeceuticals, and remedies to heal skin diseases traditionally used in the inland part of the Marches region (Central-Eastern Italy) has been conducted. At present, traditional knowledge concerning home-made phytocosmetics is represented by both the remnants of an orally transmitted folk heritage and also by new forms of knowledge, sometimes coming from popular phytotherapeutical books and the mass media (Out of the scope of this survey), but also as a result of recent migration trends from Eastern Europe. We recorded approximately 135 cosmetic or cosmeceutical preparations prepared from more than 70 botanical species and a very few animal or mineral ingredients. Among the recorded preparations, developing a clear distinction amongst cosmetics, cosmeceuticals and pharmaceuticals for skin diseases is very problematic, confirming that in folk knowledge systems medicinal products for healing skin diseases and cosmetics have often been perceived as two poles of a continuum. Many of the quoted species represented well-known medicinal plants of the European phytotherapy, although we also recorded a few unusual plant taxa, which are briefly discussed under the perspective of their eventual phytochemical and/or phytopharmacological potentialities. Exotic drugs or precious essences, even native of the Mediterranean, were not quoted as ingredients for preparing perfumes and fragrances by the interviewees of the present study, thus indicating that popular cosmetic practices in rural Central Italy have taken a much separated path away from the cosmetic "know-how" of the aristocracy and high bourgeois classes of the last centuries. (C) 2004 Elsevier Ireland Ltd. All rights reserved.
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