Ulrike Lindequist

University of Greifswald, Griefswald, Mecklenburg-Vorpommern, Germany

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Publications (186)228.03 Total impact

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    ABSTRACT: Chemical and biological investigations of the extract of Ammania auriculata (Lytheraceae) resulted in the identification of eight polyphenols (1–8) for the first time from this plant, including the gallotannin, 2,3,6-tri-O-galloyl-(α,β)-4 C1-glucopyranose (8), for which 1D and 2D-NMR spectra were recorded and assigned for the first time. The structures of all isolates (1–8) were elucidated by conventional methods, spectroscopic analysis, including 1D and 2D NMR, and by HR-ESIMS as well. All of the isolated compounds were evaluated for their antioxidant activities, determined by the DPPH and ORAC methods and for their cytotoxicity against the keratinocyte cell line HaCaT using the neutral red assay (NRU) and cell cycle analysis. Compounds 1, 3, 4, 5, and 6 significantly inhibited reactive oxygen species production with ED50 values between 3.22 and 9.79 g/ml. Compounds 1, 3, 4, and 5 showed cytotoxic activity against HaCaT cells with IC50 values between 30.7 and 84.1 g/ml. The new galloyl glucose (8) was found not cytotoxic. Ellagitannins, 2,3-hexahydroxy-(α/β)-glucopyranose (1) and 1-O-galloyl 2,3-hexahydroxy-(α)-glucopyranose (5) possess remarkable antioxidative and comparably weak cytotoxic activity.
    Pharmazie 11/2014; 69(11). · 0.96 Impact Factor
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    ABSTRACT: •The polyphenolic profile of Pittosporum angustifolium (Pittosporaceae) was studied.•Quercetin glycosides and dicaffeoylquinic acids were isolated from the leaves.•The findings support existing cladistic positioning of the Pittosporaceae.
    Biochemical Systematics and Ecology 08/2014; 55:101–103. · 1.15 Impact Factor
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    ABSTRACT: ABSTRACT Angiogenesis is a special feature in wound healing and carcinogenesis. For improving wound healing angiogenesis should be promoted, whereas in treating tumors it should be inhibited.Depending on several factors physical non-thermal plasmas can stimulate or inhibit cellular processes and can, thereby, influence angiogenesis. This study focused on effects of plasma on angiogenesis in the chick embryo chorioallantoic membrane (CAM) assay and rat aortic ring (AOR) test, in which plasma-treated PBS or medium was applied. ImageJ was used to analyze vessel area and branching of vessels of CAM’s. Aortic rings (LEW.1W, WOK.W rats) embedded in Matrigel were analyzed by a newly-developed semi-quantitative method to quantify vessel sprouting from aortic rings. In both models spontaneous vessel formation was detected. Vessel area and branching in CAM’s were significantly enhanced by 120-s-plasma-treated PBS compared to untreated controls. This result was comparable with the effect of the growth factor VEGF. No effect of plasma on vessel sprouting from AOR prepared from LEW.1W rats was detected, while it was significantly inhibited in rings of WOK.W rats. Dexamethasone inhibited vessel sprouting from AOR of both rat strains. In conclusion, angiogenic response to plasma was found to be differentially influenced, depending on the models used and on the rat strain in the AOR test. It will now be of importance to learn how plasma has to be designed for either pro- or anti-angiogenic responses.
    Lett Appl NanoBioSci. 06/2014; 3(2):159-166.
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    ABSTRACT: Three new acylated R1-barrigenol triterpene glycosides, 1-3, were isolated from the seeds of Pittosporum angustifolium Lodd. together with four known glycosides, 4-7, containing R1- and A1-barrigenol backbones. On the basis of spectroscopic, spectrometric, and chemical analyses the novel compounds were named pittangretosides N-P and established as 21beta-acetoxy-22alpha-angeloyloxy- (1), 21beta-acetoxy-22alpha-(2-acetoxy-2-methylbutyroyloxy)- (2), and 21beta-(2-methylbutyroyloxy)-22alpha-acetoxy-3beta-[beta-D-glucopyranosyl- (1 --> 2)]-[alpha-L-arabinopyranosyl-(1 --> 3)]-[alpha-L-arabinofuranosyl-(1 --> 4)]-beta-D-glucuronopyranosyloxyolean-12-ene-15alpha, 6alpha, 28-triol (3). Evaluation of the in vitro cytotoxicity against three tumour cell lines and one non-tumourigenic cell line revealed antiproliferative effects with IC50 values in a range of 1.74-34.1 microM.
    Zeitschrift für Naturforschung. C, Journal of biosciences. 05/2014; 69(5-6):191-8.
  • Evidence-based complementary and alternative medicine : eCAM. 01/2014; 2014:806180.
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    ABSTRACT: Modern non-thermal atmospheric pressure plasma sources enable controllable interaction with biological systems. Their future applications - eg wound management - are based on their unique mixture of reactive components sparking both stimulatory as well as inhibitory processes. To gain detailed understanding of plasma- cell interaction and with respect to risk awareness, key mechanisms need to be identified. This study focuses on the impact of an argon non-thermal atmospheric pressure plasma jet (kINPen 09) on human HaCaT keratinocytes. With increasing duration, cell viability decreased. In accordance, cells accumulated in G2/M phase within the following 24 h. DNA single-strand breaks were detected immediately after treatment and receded in the aftermath, returning to control levels after 24 h. No directly plasma-related DNA double- strand breaks were detected over the same time. Concurrently, DNA synthesis decreased. Coincident with treatment time, an increase in intracellular 2',7'-dichlorodihydrofluorescein diacetate (H2 DCFDA) conversion increased reactive oxygen species (ROS) levels. The radical scavenging activity of culture medium crucially influenced these effects. Thus, ROS changed DNA integrity, and the effectiveness of cellular defence mechanisms characterizes the interaction of non-thermal plasma and eukaryotic cells. Effects were time-dependent, indicating an active response of the eukaryotic cells. Hence, a stimulation of eukaryotic cells using short-term non-thermal plasma treatment seems possible, eg in the context of chronic wound care. Long-term plasma treatments stopped in cell proliferation and apoptosis, which might be relevant in controlling neoplastic conditions.
    Cell Biology International 10/2013; · 1.64 Impact Factor
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    ABSTRACT: Phytochemical investigation of the leaves of Pittosporum angustifolium resulted in the isolation and structural elucidation of nine new triterpene saponins, named pittangretosides A-I (1-9), together with a known compound (10). Mainly by NMR and HRESIMS experiments, eight compounds were identified as A1-barrigenol glycosides (1-7, 10), whereas two compounds exhibited an unusual 17,22-seco-backbone of oleanolic acid (8, 9). All compounds were evaluated for their in vitro cytotoxicities against human urinary bladder carcinoma cells (5637). Only compounds with an angeloyl-residue at C-22 of the aglycone (1-4 and 10) showed antiproliferative effects with IC50 values of 4.1, 5.2, 2.1, 17.9, and 2.4 µM, respectively.
    Planta Medica 09/2013; · 2.35 Impact Factor
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    ABSTRACT: Two farnesylhydroquinones were isolated from the fruiting bodies of Ganoderma pfeifferi, farnesylhydroquinone (1) and the new compound ganomycin K (2), (5S)-3-[(E)-7,8-dihydroxy-4,8-dimethylnon-3-enyl]-5-(2,5-dihydroxyphenyl)-furan-2(5H)-one. The structures of 1 and 2 were determined on the basis of mass spectrometric and NMR spectroscopic evidence. The antibacterial activity of the isolated compounds was neglectable.
    Natural Products and Bioprospecting. 09/2013; 3:137-140.
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    Muftah Ali M Shushni, Faizul Azam, Ulrike Lindequist
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    ABSTRACT: Because of the evolving resistance of microorganisms against existing antibiotics, there is an increasing need for new ones, not only in human, but also in veterinary medicine. The dichloromethane extract of a fungal strain of the genus Lophiostoma, isolated from driftwood collected from the coast of the Baltic Sea, displayed antibacterial activity against some fish pathogenic bacteria. Ergosterol epoxide (1), cerebroside C (2) and oxasetin (3) were isolated from the extract and structurally elucidated on the basis of spectroscopic data and chemical evidence. Compound 3 exhibited in vitro activity against Vibrio anguillarum, Flexibacter maritimus and Pseudomonas anguilliseptica with minimal inhibitory concentrations of 12.5, 12.5 and 6.25 microg/mL, respectively. Molecular docking studies were performed to understand the interaction of compound 3 with different macromolecular targets. Analysis of in silico results, together with experimental findings, validates the antimicrobial activity associated with compound 3. These results may be exploited in lead optimization and development of potent antibacterial agents.
    Natural product communications 09/2013; 8(9):1223-6. · 0.96 Impact Factor
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    ABSTRACT: Novel halogenated 2-vinylchromanones were prepared which show a strong growth inhibition toward Gram-negative bacteria. The activity pattern is different to previously reported derivatives and depends on the position of the halogen substituent. Graphical abstract
    Monatshefte fuer Chemie/Chemical Monthly 07/2013; 144(3). · 1.63 Impact Factor
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    ABSTRACT: During the last years the use of physical plasma for medical applications has grown rapidly. A multitude of findings about plasma-cell and plasma-tissue interactions and its possible use in therapy have been provided. One of the key findings of plasma medical basic research is that several biological effects do not result from direct plasma-cell or plasma-tissue interaction but are mediated by liquids. Above all, it was demonstrated that simple liquids like water or physiological saline, are antimicrobially active after treatment by atmospheric pressure plasma and that these effects are attributable to the generation of different low-molecular reactive species. Besides, it could be shown that plasma treatment leads to the stimulation of specific aspects of cell metabolism and to a transient and reversible increase of diffusion properties of biological barriers. All these results gave rise to think about another new and innovative field of medical plasma application. In contrast to plasma medicine, which means the direct use of plasmas on or in the living organism for direct therapeutic purposes, this field - as a specific field of medical plasma application - is called plasma pharmacy. Based on the present state of knowledge, most promising application fields of plasma pharmacy might be: plasma-based generation of biologically active liquids; plasma-based preparation, optimization, or stabilization of - mainly liquid - pharmaceutical preparations; support of drug transport across biological barriers; plasma-based stimulation of biotechnological processes.
    Pharmazie 07/2013; 68(7):492-8. · 0.96 Impact Factor
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    ABSTRACT: In the field of wound healing research non-thermal plasma (NTP) increasingly draws attention. Next to its intensely studied antibacterial effects, some studies already showed stimulating effects on eukaryotic cells. This promises a unique potential in healing of chronic wounds, where effective therapies are urgently needed. Immune cells do play an important part in the process of wound healing and their reaction to NTP treatment has yet been rarely examined. Here, we studied the impact of NTP treatment using the kinpen on apoptotic and proliferative cell signaling pathways of two human immune cell lines, the CD4(+)T helper cell line Jurkat and the monocyte cell line THP-1. Depending on NTP treatment time the number of apoptotic cells increased in both investigated cell types according to a caspase 3 assay. Western blot analysis pointed out that plasma treatment activated pro-apoptotic signaling proteins like p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase 1 and 2 (JNK 1/2) in both cell types. Stronger signals were detected in Jurkat cells at comparable plasma treatment times. Intriguingly, exposure of Jurkat and THP-1 cells to plasma also activated the pro-proliferative signaling molecules extracellular signal-regulated kinase 1/2 (ERK 1/2) and MAPK/ERK kinase 1 and 2 (MEK 1/2). In contrast to Jurkat cells, the anti-apoptotic heat shock protein 27 (HSP27) was activated in THP-1 cells after plasma treatment, indicating a possible mechanism how THP-1 cells may reduce programmed cell death. In conclusion, several signaling cascades were activated in the examined immune cell lines after NTP treatment and in THP-1 monocytes a possible defense mechanism against plasma impacts could be revealed. Therefore, plasma might be a treatment option for wound healing.
    Immunobiology 05/2013; · 2.81 Impact Factor
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    ABSTRACT: In a previous paper we demonstrated the results of biological screening of Yemeni basidiomycetes. The present study was aimed to investigate the antimicrobial and the antioxidant activity of further basidiomycetes collected in Yemen. Dichloromethane, methanol and aqueous extracts of the fruiting bodies of 25 species were screened in vitro for their antibacterial activities against three Gram-positive bacteria (Staphyloccocus aureus, Bacillus subtilis, Micrococcus flavus) and two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), against six human fungal pathogens (Candida albicans, Candida krusei, Aspergillus fumigatus, Mucor sp., Microsporum gypseum, Trichophyton mentagrophytes) and against one non human pathogenic fungus (Candida maltosa). The results indicated that 75 extracts exhibited activity against one or more of the bacteria. The methanol extracts of Agaricus cf. bernardii, Agrocybe pediades, Chlorophyllum molybdites, Coriolopsis polyzona, Ganoderma xylonoides, Pycnoporus sanguineus, Trametes lactinea and Trametes cingulata showed activity against all tested bacteria. The highest antibacterial activity was exhibited by methanol extracts from Chlorophyllum molybdites, Ganoderma xylonoides and Trametes cingulata and Agaricus cf. bernardii, Agrocybe pediades, Coriolopsis polyzona, Pycnoporus sanguineus and Trametes lactinea. The methanol extracts of Chlorophyllum molybdites, Ganoderma xylonoides and Pycnoporus sanguineus showed considerable antifungal activities against the tested fungal strains. Strong antioxidative effects employing the DPPH assay were exhibited by methanol extracts from Chlorophyllum molybdites, Ganoderma xylonoides, Hexagonia velutina, Pycnoporus sanguineus, Trametes lactinea and Trametes cingulata. Our previous and presented studies about 48 basidiomycetes collected in Yemen provide evidence that basidiomycetes from the Arabic region so far should attract more attention as potential source for new biologically active agents.
    Pharmazie 03/2013; 68(3):221-6. · 0.96 Impact Factor
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    ABSTRACT: BACKGROUND: The use of non-thermal atmospheric pressure plasma in dermatology to improve the healing of chronic wounds is a promising application. The antimicrobial properties of physical plasma offer on the one hand the killing of bacteria, which are often a problem in chronic wounds. On the other hand, plasma can activate cells which are involved in the wound closure. OBJECTIVE: To guarantee a safe application it is essential to understand basic interactions between physical plasma and human skin cells. METHODS: In our study, human keratinocytes (HaCaT cells) were directly plasma treated with a dielectric barrier discharge (DBD) plasma source and effects on viability, DNA, cell cycle, intracellular concentration of reactive oxygen species and induction of apoptosis were observed. RESULTS: A treatment time-dependent loss of recovered adherent HaCaT cells after 24h and a linear increase of DNA damage were observed, which was no longer evident 24h after plasma stimulation, except for long treatment times. An accumulation of HaCaT cells in G2/M phase and a decrease in the G1 phase was caused by DBD plasma. The increasing formation of intracellular ROS is also attributed to plasma treatment. In contrast to other studies we did not find clear evidences for apoptosis in adherent HaCaT cells. A culture medium exchange subsequently after plasma treatment weakened the observed effects. CONCLUSION: DBD plasma treatment resulted in oxidative stress in human keratinocytes which is related to deficient cell performance.
    Journal of dermatological science 02/2013; · 3.71 Impact Factor
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  • Biochem Anal Biochem 2013; 01/2013
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    ABSTRACT: Adequate chronic wound healing is a major problem in medicine. A new solution might be non-thermal atmospheric-pressure plasma effectively inactivating microorganisms and influencing cells in wound healing. Plasma components as, for example, radicals can affect cells differently. HaCaT keratinocytes were treated with Dielectric Barrier Discharge plasma (DBD/air, DBD/argon), ozone or hydrogen peroxide to find the components responsible for changes in integrin expression, intracellular ROS formation or apoptosis induction. Dependent on plasma treatment time reduction of recovered cells was observed with no increase of apoptotic cells, but breakdown of mitochondrial membrane potential. DBD/air plasma increased integrins and intracellular ROS. DBD/argon caused minor changes. About 100 ppm ozone did not influence integrins. Hydrogen peroxide caused similar effects compared to DBD/air plasma. In conclusion, effects depended on working gas and exposure time to plasma. Short treatment cycles did neither change integrins nor induce apoptosis or ROS. Longer treatments changed integrins as important for influencing wound healing. Plasma effects on integrins are rather attributed to induction of other ROS than to generation of ozone. Changes of integrins by plasma may provide new solutions of improving wound healing, however, conditions are needed which allow initiating the relevant influence on integrins without being cytotoxic to cells.
    BioMed research international. 01/2013; 2013:761451.
  • Ulrike Lindequist
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    ABSTRACT: Whereas pharmaceuticals prepared by extraction of medicinal plants constitute an important part of evidence-based medicine also in the Western Hemisphere, medicinal mushrooms are mainly used as dietary supplements without declaration of a medical indication. Scientific investigations and case studies from Asian medicine show that fungi have very promising pharmacological potential. This article provides an overview of the principles of authorization and market access of herbal drugs in Europe, with special reference to Germany. The current status regarding mushrooms is reported, with an aim toward supporting the development of legalized pharmaceutical preparations of medicinal mushrooms in Europe.
    International journal of medicinal mushrooms. 01/2013; 15(6):517-523.
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    Ashraf Saif, Kristian Wende, Ulrike Lindequist
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    ABSTRACT: The effect of Lentinula edodes water extract (LE) on two osteoblastic cell cultures (HOS 58 and Saos-2) was investigated to determine if this edible medicinal mushroom has osteoinductive properties. Activity of alkaline phosphatase and mineralization were used as indicators for the vitality and maturation of the bone cells. Cultivation of human osteosarcoma cells HOS 58 for five days in presence of a serial dilution of the aqueous extract of L. edodes (0.8 μg/mL-125 μg/mL) resulted in a significant elevation of alkaline phosphatase activity (ALP) of the cells in comparison to untreated cells. Saos-2 cells, incubated with LE (20 μg/mL) and β-glycerol phosphate (2 mM) for 21 days, displayed a 2 fold level of mineralization than cells cultured soley with the positive control, β-glycerophosphate. The obtained results clearly indicate the activity of LE as a bone inducing agent in vitro. Therefore, the shiitake mushroom (L. edodes) deserves attention as a supportive dietary treatment or nutraceutical in the case of diseases accompanied with bone disorder, such as osteoporosis, osteopenia, and late complication of diabetes.
    Natural Products and Bioprospecting. 01/2013;
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    ABSTRACT: In the field of wound healing research non-thermal plasma (NTP) has attracted increasing attention over the last decades. NTP has a complex composition and consists of ions, exited atoms, electrons, ultraviolet (UV) light, visible and infrared radiation, neutral molecules, and free radicals e.g. reactive oxygen and nitrogen species (ROS/RNS)1. Next to its well-established antibacterial effects it has potential proliferation promoting properties on eukaryotic cells2. Although a number of studies have been carried out to investigate the impact of NTP on human cells, not much is known about the influences on the molecular level. In order to shed some light in the complex impact NTP has on wound healing, this study analyzed in detail the differential gene expression pattern of human cells involved in this process in response to NTP treatment. Besides the keratinocyte cell line HaCaT, two immune cells lines were studied - the CD4+ T helper cell line Jurkat and the monocyte cell line THP-1.
    Plasma Science (ICOPS), 2013 Abstracts IEEE International Conference on; 01/2013

Publication Stats

1k Citations
228.03 Total Impact Points


  • 1989–2014
    • University of Greifswald
      • • Institute of Pharmacy
      • • Institute for Microbiology
      • • Pharmaceutical Biology Group
      • • Faculty of Mathematics and Natural Sciences
      Griefswald, Mecklenburg-Vorpommern, Germany
  • 2013
    • University of Benghazi
      Bengasi, Banghāzī, Libya
    • Leibniz Institute for Plasma Science and Technology
      Griefswald, Mecklenburg-Vorpommern, Germany
  • 2005–2013
    • Aden University
      • Department of Pharmacognosy
      Aden, Aden, Yemen
  • 2012
    • Umm Al-Qura University
      Makkah, Makkah, Saudi Arabia
  • 2001–2012
    • Sana'a University
      Şan‘ā’, Sanaa, Yemen
  • 2011
    • University of Tuebingen
      Tübingen, Baden-Württemberg, Germany
    • The University of Garyounis
      Box Elder, South Dakota, United States
  • 2010
    • Ain Shams University
      • Department of Pharmacognosy
      Cairo, Muhafazat al Qahirah, Egypt
    • King Saud University
      • College of Pharmacy
      Riyadh, Mintaqat ar Riyad, Saudi Arabia
  • 2009
    • University of Rostock
      • Institut für Chemie
      Rostock, Mecklenburg-Vorpommern, Germany
  • 2003–2008
    • Institute Of The Chemistry Of Plant Substances
      Toshkent, Toshkent Shahri, Uzbekistan
  • 2007
    • Tribhuvan University
      • Research Centre for Applied Science and Technology (RECAST)
      Kantipura, Central Region, Nepal